[E3-hacking] [RFC] [PATCH 1/6] SoC Camera: add driver for OMAP1 camera interface

Guennadi Liakhovetski g.liakhovetski at gmx.de
Fri Jul 30 12:07:42 BST 2010


Hi Janusz

Thanks once more for the patches, from your patches it is obvious, that 
you've spent quite a bit of time on them and you have not just copy-pasted 
various bits and pieces from other drivers, just filling your hardware 
details, but you also actually understand a lot of what is actually going 
on in there. So, I think, fixing remaining mostly minor issues shouldn't 
be too difficult for you either.

On Sun, 18 Jul 2010, Janusz Krzysztofik wrote:

> This is a V4L2 driver for TI OMAP1 SoC camera interface.
> 
> Two versions of the driver are provided, using either videobuf-dma-contig or 
> videobuf-dma-sg. The former uses less processing power, but often fails to 
> allocate contignuous buffer memory. The latter is free of this problem, but 
> generates tens of DMA interrupts per frame.

Hm, would it be difficult to first try contig, and if it fails - fall back 
to sg?

In its present state buffer management in your driver is pretty difficult 
to follow. At the VERY least you have to extensively document your buffer 
manipulations. Better yet clean it up. AFAIU, your "ready" pointer is 
pretty much unused in the contiguous case. Or you can easily get rid of 
it. So, I think, a very welcome improvement to the driver would be a 
cleaner separation between the two cases. Don't try that much to reuse the 
code as much as possible. Would be much better to have clean separation 
between the two implementations - whether dynamically switchable at 
runtime or at config time - would be best to separate the two 
implementations to the point, where each of them becomes understandable 
and maintainable.

So, I will do a pretty formal review this time and wait for v2. And in v2 
I'd like to at the very least see detailed buffer-management 
documentation, or - better yet - a rework with a clean separation.

> Both versions work stable for me, 
> even under heavy load, on my OMAP1510 based Amstrad Delta videophone, that is 
> the oldest, least powerfull OMAP1 implementation.
> 
> The interface generally works in pass-through mode. Since input data byte 
> endianess can be swapped, it provides up to two v4l2 pixel formats per each of 
> several soc_mbus formats that have their swapped endian counterparts.
> 
> Boards using this driver can provide it with the followning information:
> - if and what freqency clock is expected by an on-board camera sensor,
> - what is the maximum pixel clock that should be accepted from the sensor,
> - what is the polarity of the sensor provided pixel clock,
> - if the interface GPIO line is connected to a sensor reset/powerdown input 
>   and what is the input polarity.
> 
> Created and tested against linux-2.6.35-rc3 on Amstrad Delta.
> 
> Signed-off-by: Janusz Krzysztofik <jkrzyszt at tis.icnet.pl>
> ---
>  drivers/media/video/Kconfig        |   14
>  drivers/media/video/Makefile       |    1
>  drivers/media/video/omap1_camera.c | 1656 +++++++++++++++++++++++++++++++++++++
>  include/media/omap1_camera.h       |   16
>  4 files changed, 1687 insertions(+)
> 
> --- linux-2.6.35-rc3.orig/include/media/omap1_camera.h	1970-01-01 01:00:00.000000000 +0100
> +++ linux-2.6.35-rc3/include/media/omap1_camera.h	2010-07-18 01:31:57.000000000 +0200
> @@ -0,0 +1,16 @@

A copyright / licence header here, please

> +#ifndef __MEDIA_OMAP1_CAMERA_H_
> +#define __MEDIA_OMAP1_CAMERA_H_
> +
> +#define OMAP1_CAMERA_IOSIZE		0x1c
> +
> +struct omap1_cam_platform_data {
> +	unsigned long camexclk_khz;
> +	unsigned long lclk_khz_max;
> +	unsigned long flags;
> +};
> +
> +#define OMAP1_CAMERA_LCLK_RISING	BIT(0)
> +#define OMAP1_CAMERA_RST_LOW		BIT(1)
> +#define OMAP1_CAMERA_RST_HIGH		BIT(2)

Then you need to #include <linux/bitops.h>

> +
> +#endif /* __MEDIA_OMAP1_CAMERA_H_ */
> --- linux-2.6.35-rc3.orig/drivers/media/video/Kconfig	2010-06-26 15:55:29.000000000 +0200
> +++ linux-2.6.35-rc3/drivers/media/video/Kconfig	2010-07-02 04:12:02.000000000 +0200
> @@ -962,6 +962,20 @@ config VIDEO_SH_MOBILE_CEU
>  	---help---
>  	  This is a v4l2 driver for the SuperH Mobile CEU Interface
>  
> +config VIDEO_OMAP1
> +	tristate "OMAP1 Camera Interface driver"
> +	depends on VIDEO_DEV && ARCH_OMAP1 && SOC_CAMERA
> +	select VIDEOBUF_DMA_CONTIG if !VIDEO_OMAP1_SG
> +	---help---
> +	  This is a v4l2 driver for the TI OMAP1 camera interface
> +
> +if VIDEO_OMAP1

Don't think you need this "if," the "depends on" below should suffice.

> +config VIDEO_OMAP1_SG
> +	bool "Scatter-gather mode"
> +	depends on VIDEO_OMAP1 && EXPERIMENTAL
> +	select VIDEOBUF_DMA_SG
> +endif
> +
>  config VIDEO_OMAP2
>  	tristate "OMAP2 Camera Capture Interface driver"
>  	depends on VIDEO_DEV && ARCH_OMAP2
> --- linux-2.6.35-rc3.orig/drivers/media/video/Makefile	2010-06-26 15:55:29.000000000 +0200
> +++ linux-2.6.35-rc3/drivers/media/video/Makefile	2010-06-26 17:28:09.000000000 +0200
> @@ -165,6 +165,7 @@ obj-$(CONFIG_VIDEO_MX1)			+= mx1_camera.
>  obj-$(CONFIG_VIDEO_MX3)			+= mx3_camera.o
>  obj-$(CONFIG_VIDEO_PXA27x)		+= pxa_camera.o
>  obj-$(CONFIG_VIDEO_SH_MOBILE_CEU)	+= sh_mobile_ceu_camera.o
> +obj-$(CONFIG_VIDEO_OMAP1)		+= omap1_camera.o
>  
>  obj-$(CONFIG_ARCH_DAVINCI)		+= davinci/
>  
> --- linux-2.6.35-rc3.orig/drivers/media/video/omap1_camera.c	1970-01-01 01:00:00.000000000 +0100
> +++ linux-2.6.35-rc3/drivers/media/video/omap1_camera.c	2010-07-18 01:32:48.000000000 +0200
> @@ -0,0 +1,1656 @@
> +/*
> + * V4L2 SoC Camera driver for OMAP1 Camera Interface
> + *
> + * Copyright (C) 2010, Janusz Krzysztofik <jkrzyszt at tis.icnet.pl>
> + *
> + * Based on V4L2 Driver for i.MXL/i.MXL camera (CSI) host
> + * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas at teltonika.lt>
> + * Copyright (C) 2009, Darius Augulis <augulis.darius at gmail.com>
> + *
> + * Based on PXA SoC camera driver
> + * Copyright (C) 2006, Sascha Hauer, Pengutronix
> + * Copyright (C) 2008, Guennadi Liakhovetski <kernel at pengutronix.de>
> + *
> + * Hardware specific bits initialy based on former work by Matt Callow
> + * drivers/media/video/omap/omap1510cam.c
> + * Copyright (C) 2006 Matt Callow
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/version.h>
> +
> +#include <media/omap1_camera.h>
> +#include <media/soc_camera.h>
> +#include <media/soc_mediabus.h>
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +#include <media/videobuf-dma-contig.h>
> +#else
> +#include <media/videobuf-dma-sg.h>
> +#endif

I think, you can just include both headers.

> +
> +#include <plat/dma.h>
> +
> +
> +#define DRIVER_NAME		"omap1-camera"
> +#define VERSION_CODE		KERNEL_VERSION(0, 0, 1)
> +
> +
> +/*
> + * ---------------------------------------------------------------------------
> + *  OMAP1 Camera Interface registers
> + * ---------------------------------------------------------------------------
> + */
> +
> +#define REG_CTRLCLOCK		0x00
> +#define REG_IT_STATUS		0x04
> +#define REG_MODE		0x08
> +#define REG_STATUS		0x0C
> +#define REG_CAMDATA		0x10
> +#define REG_GPIO		0x14
> +#define REG_PEAK_COUNTER	0x18
> +
> +/* CTRLCLOCK bit shifts */
> +#define LCLK_EN			BIT(7)
> +#define DPLL_EN			BIT(6)
> +#define MCLK_EN			BIT(5)
> +#define CAMEXCLK_EN		BIT(4)
> +#define POLCLK			BIT(3)
> +#define FOSCMOD_SHIFT		0
> +#define FOSCMOD_MASK		(0x7 << FOSCMOD_SHIFT)
> +#define FOSCMOD_12MHz		0x0
> +#define FOSCMOD_6MHz		0x2
> +#define FOSCMOD_9_6MHz		0x4
> +#define FOSCMOD_24MHz		0x5
> +#define FOSCMOD_8MHz		0x6
> +
> +/* IT_STATUS bit shifts */
> +#define DATA_TRANSFER		BIT(5)
> +#define FIFO_FULL		BIT(4)
> +#define H_DOWN			BIT(3)
> +#define H_UP			BIT(2)
> +#define V_DOWN			BIT(1)
> +#define V_UP			BIT(0)
> +
> +/* MODE bit shifts */
> +#define RAZ_FIFO		BIT(18)
> +#define EN_FIFO_FULL		BIT(17)
> +#define EN_NIRQ			BIT(16)
> +#define THRESHOLD_SHIFT		9
> +#define THRESHOLD_MASK		(0x7f << THRESHOLD_SHIFT)
> +#define DMA			BIT(8)
> +#define EN_H_DOWN		BIT(7)
> +#define EN_H_UP			BIT(6)
> +#define EN_V_DOWN		BIT(5)
> +#define EN_V_UP			BIT(4)
> +#define ORDERCAMD		BIT(3)
> +
> +#define IRQ_MASK		(EN_V_UP | EN_V_DOWN | EN_H_UP | EN_H_DOWN | \
> +				 EN_NIRQ | EN_FIFO_FULL)
> +
> +/* STATUS bit shifts */
> +#define HSTATUS			BIT(1)
> +#define VSTATUS			BIT(0)
> +
> +/* GPIO bit shifts */
> +#define CAM_RST			BIT(0)
> +
> +/* end of OMAP1 Camera Interface registers */
> +
> +
> +#define SOCAM_BUS_FLAGS	(SOCAM_MASTER | \
> +			SOCAM_HSYNC_ACTIVE_HIGH | SOCAM_VSYNC_ACTIVE_HIGH | \
> +			SOCAM_PCLK_SAMPLE_RISING | SOCAM_PCLK_SAMPLE_FALLING | \
> +			SOCAM_DATA_ACTIVE_HIGH | SOCAM_DATAWIDTH_8)
> +
> +
> +#define CAM_EXCLK_6MHz		 6000000
> +#define CAM_EXCLK_8MHz		 8000000
> +#define CAM_EXCLK_9_6MHz	 9600000
> +#define CAM_EXCLK_12MHz		12000000
> +#define CAM_EXCLK_24MHz		24000000

Why do you need this? Your platform specifies the EXCLK frequency directly 
in kHz, then you multiplly it by 1000 to get pcdev->camexclk in Hz, then 
you compare it to these macros. Don't think you need them - just use 
numbers directly.

> +
> +
> +#define FIFO_SIZE		((THRESHOLD_MASK >> THRESHOLD_SHIFT) + 1)
> +#define FIFO_SHIFT		__fls(FIFO_SIZE)
> +
> +#define DMA_BURST_SHIFT		(1 + OMAP_DMA_DATA_BURST_4)
> +#define DMA_BURST_SIZE		(1 << DMA_BURST_SHIFT)
> +
> +#define DMA_ELEMENT_SHIFT	OMAP_DMA_DATA_TYPE_S32
> +#define DMA_ELEMENT_SIZE	(1 << DMA_ELEMENT_SHIFT)
> +
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +#define DMA_FRAME_SHIFT		(FIFO_SHIFT - 1)
> +#define MIN_BUF_COUNT		3
> +#else
> +#define DMA_FRAME_SHIFT		DMA_BURST_SHIFT
> +#define MIN_BUF_COUNT		2
> +#endif
> +
> +#define DMA_FRAME_SIZE		(1 << DMA_FRAME_SHIFT)
> +#define DMA_SYNC		OMAP_DMA_SYNC_FRAME
> +#define THRESHOLD_LEVEL		DMA_FRAME_SIZE
> +
> +
> +#define MAX_VIDEO_MEM		4	/* arbitrary video memory limit in MB */
> +
> +
> +/*
> + * Structures
> + */
> +
> +/* buffer for one video frame */
> +struct omap1_cam_buf {
> +	struct videobuf_buffer		vb;
> +	enum v4l2_mbus_pixelcode	code;
> +	int				inwork;
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +	struct scatterlist		*sgbuf;
> +	int				sgcount;
> +	int				bytes_left;
> +	enum videobuf_state		result;
> +#endif
> +};
> +
> +struct omap1_cam_dev {
> +	struct soc_camera_host		soc_host;
> +	struct soc_camera_device	*icd;
> +	struct clk			*clk;
> +
> +	unsigned int			irq;
> +	void __iomem			*base;
> +
> +	int				dma_ch;
> +
> +	struct omap1_cam_platform_data	*pdata;
> +	struct resource			*res;
> +	unsigned long			pflags;
> +	unsigned long			camexclk;
> +
> +	struct list_head		capture;
> +
> +	spinlock_t			lock;
> +
> +	/* Pointers to DMA buffers */
> +	struct omap1_cam_buf		*active;
> +	struct omap1_cam_buf		*ready;

Well, I must confess, as it stands, you managed to confuse me with your 
"active" and "ready" buffer management. Is the reason for these two 
pointers some hardware feature? Maybe that while one buffer is being 
filled by DMA you can already configure the DMA engine with the next one?

> +
> +	u32			reg_cache[OMAP1_CAMERA_IOSIZE / sizeof(u32)];

Don't think you'd lose much performance without cache, for that the code 
would become less error-prone.

> +};
> +
> +
> +void cam_write(struct omap1_cam_dev *pcdev, u16 reg, u32 val)

static

> +{
> +	pcdev->reg_cache[reg / sizeof(u32)] = val;
> +	__raw_writel(val, pcdev->base + reg);
> +}
> +
> +int cam_read(struct omap1_cam_dev *pcdev, u16 reg, bool from_cache)

static u32

> +{
> +	return !from_cache ? __raw_readl(pcdev->base + reg) :
> +			pcdev->reg_cache[reg / sizeof(u32)];

hmmm.... it's never simple with caches;) Some registers (e.g., CTRLCLOCK) 
you read both from the cache and from the hardware directly. Don't you 
have to update the cache on a direct read?

> +}
> +
> +#define CAM_READ(pcdev, reg) \
> +		cam_read(pcdev, REG_##reg, 0)

last parameter is a bool, so, use "false"

> +#define CAM_WRITE(pcdev, reg, val) \
> +		cam_write(pcdev, REG_##reg, val)
> +#define CAM_READ_CACHE(pcdev, reg) \
> +		cam_read(pcdev, REG_##reg, 1)

"true"

> +
> +/*
> + *  Videobuf operations
> + */
> +static int omap1_videobuf_setup(struct videobuf_queue *vq, unsigned int *count,
> +		unsigned int *size)
> +{
> +	struct soc_camera_device *icd = vq->priv_data;
> +	int bytes_per_line = soc_mbus_bytes_per_line(icd->user_width,
> +			icd->current_fmt->host_fmt);
> +
> +	if (bytes_per_line < 0)
> +		return bytes_per_line;
> +
> +	*size = bytes_per_line * icd->user_height;
> +
> +	if (!*count || *count < MIN_BUF_COUNT)
> +		*count = MIN_BUF_COUNT;
> +
> +	if (*size * *count > MAX_VIDEO_MEM * 1024 * 1024)
> +		*count = (MAX_VIDEO_MEM * 1024 * 1024) / *size;
> +
> +	dev_dbg(icd->dev.parent,
> +			"%s: count=%d, size=%d\n", __func__, *count, *size);
> +
> +	return 0;
> +}
> +
> +static void free_buffer(struct videobuf_queue *vq, struct omap1_cam_buf *buf)
> +{
> +	struct videobuf_buffer *vb = &buf->vb;
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +	struct videobuf_dmabuf *dma = videobuf_to_dma(vb);
> +#endif
> +
> +	BUG_ON(in_interrupt());
> +
> +	videobuf_waiton(vb, 0, 0);
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	videobuf_dma_contig_free(vq, vb);
> +#else
> +	videobuf_dma_unmap(vq, dma);
> +	videobuf_dma_free(dma);
> +#endif
> +
> +	vb->state = VIDEOBUF_NEEDS_INIT;
> +}
> +
> +static int omap1_videobuf_prepare(struct videobuf_queue *vq,
> +		struct videobuf_buffer *vb, enum v4l2_field field)
> +{
> +	struct soc_camera_device *icd = vq->priv_data;
> +	struct omap1_cam_buf *buf = container_of(vb, struct omap1_cam_buf, vb);
> +	int bytes_per_line = soc_mbus_bytes_per_line(icd->user_width,
> +			icd->current_fmt->host_fmt);
> +	int ret;
> +
> +	if (bytes_per_line < 0)
> +		return bytes_per_line;
> +
> +	WARN_ON(!list_empty(&vb->queue));
> +
> +	BUG_ON(NULL == icd->current_fmt);
> +
> +	buf->inwork = 1;
> +
> +	if (buf->code != icd->current_fmt->code ||
> +			vb->width  != icd->user_width ||
> +			vb->height != icd->user_height ||
> +			vb->field  != field) {
> +		buf->code  = icd->current_fmt->code;
> +		vb->width  = icd->user_width;
> +		vb->height = icd->user_height;
> +		vb->field  = field;
> +		vb->state  = VIDEOBUF_NEEDS_INIT;
> +	}
> +
> +	vb->size = bytes_per_line * vb->height;
> +
> +	if (vb->baddr && vb->bsize < vb->size) {
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (vb->state == VIDEOBUF_NEEDS_INIT) {
> +		ret = videobuf_iolock(vq, vb, NULL);
> +		if (ret)
> +			goto fail;
> +
> +		vb->state = VIDEOBUF_PREPARED;
> +	}
> +	buf->inwork = 0;
> +
> +	return 0;
> +fail:
> +	free_buffer(vq, buf);
> +out:
> +	buf->inwork = 0;
> +	return ret;
> +}
> +
> +static void set_dma_dest_params(int dma_ch, struct omap1_cam_buf *buf)
> +{
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	dma_addr_t dma_addr = videobuf_to_dma_contig(&buf->vb);
> +	unsigned int block_size = buf->vb.size;
> +#else
> +	dma_addr_t dma_addr;
> +	unsigned int block_size;
> +
> +	if (WARN_ON(!buf->sgbuf)) {
> +		buf->result = VIDEOBUF_ERROR;
> +		return;
> +	}
> +	dma_addr = sg_dma_address(buf->sgbuf);
> +	if (WARN_ON(!dma_addr)) {
> +		buf->sgbuf = NULL;
> +		buf->result = VIDEOBUF_ERROR;
> +		return;
> +	}
> +	block_size = sg_dma_len(buf->sgbuf);
> +	if (WARN_ON(!block_size)) {
> +		buf->sgbuf = NULL;
> +		buf->result = VIDEOBUF_ERROR;
> +		return;
> +	}
> +	if (unlikely(buf->bytes_left < block_size))
> +		block_size = buf->bytes_left;
> +	if (WARN_ON(dma_addr & (DMA_FRAME_SIZE * DMA_ELEMENT_SIZE - 1))) {
> +		dma_addr = ALIGN(dma_addr, DMA_FRAME_SIZE * DMA_ELEMENT_SIZE);
> +		block_size &= ~(DMA_FRAME_SIZE * DMA_ELEMENT_SIZE - 1);
> +	}
> +	buf->bytes_left -= block_size;
> +	buf->sgcount++;
> +#endif
> +	omap_set_dma_dest_params(dma_ch, OMAP_DMA_PORT_EMIFF,
> +			OMAP_DMA_AMODE_POST_INC, dma_addr, 0, 0);
> +	omap_set_dma_transfer_params(dma_ch, OMAP_DMA_DATA_TYPE_S32,
> +			DMA_FRAME_SIZE, block_size >> (DMA_FRAME_SHIFT +
> +			DMA_ELEMENT_SHIFT), DMA_SYNC, 0, 0);
> +}
> +
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +static struct scatterlist *try_next_sgbuf(int dma_ch, struct omap1_cam_buf *buf)
> +{
> +	struct scatterlist *sgbuf;
> +
> +	if (likely(buf->sgbuf)) {
> +
> +		if (unlikely(!buf->bytes_left)) {
> +			/* indicate sglist complete */
> +			sgbuf = NULL;
> +		} else {
> +			sgbuf = sg_next(buf->sgbuf);
> +			if (WARN_ON(!sgbuf)) {
> +				buf->result = VIDEOBUF_ERROR;
> +			} else if (WARN_ON(!sg_dma_len(sgbuf))) {
> +				sgbuf = NULL;
> +				buf->result = VIDEOBUF_ERROR;
> +			}
> +		}
> +		buf->sgbuf = sgbuf;
> +	} else {
> +		struct videobuf_dmabuf *dma = videobuf_to_dma(&buf->vb);
> +
> +		buf->sgbuf = sgbuf = dma->sglist;
> +		if (sgbuf) {
> +			buf->sgcount = 0;
> +			buf->bytes_left = buf->vb.size;
> +			buf->result = VIDEOBUF_DONE;
> +		}
> +	}
> +	if (sgbuf)
> +		set_dma_dest_params(dma_ch, buf);
> +
> +	return sgbuf;
> +}
> +#endif
> +
> +static struct omap1_cam_buf *prepare_next_vb(struct omap1_cam_dev *pcdev)
> +{
> +	struct omap1_cam_buf *buf;
> +
> +	buf = pcdev->ready;
> +	if (!buf) {
> +		if (list_empty(&pcdev->capture))
> +			return buf;
> +		buf = list_entry(pcdev->capture.next,
> +				struct omap1_cam_buf, vb.queue);
> +		buf->vb.state = VIDEOBUF_ACTIVE;
> +		pcdev->ready = buf;
> +		list_del_init(&buf->vb.queue);
> +	}
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	set_dma_dest_params(pcdev->dma_ch, buf);
> +#else
> +	buf->sgbuf = NULL;
> +#endif
> +	return buf;
> +}
> +
> +static void start_capture(struct omap1_cam_dev *pcdev)
> +{
> +	struct omap1_cam_buf *buf = pcdev->active;
> +	unsigned long ctrlclock = CAM_READ_CACHE(pcdev, CTRLCLOCK);
> +	unsigned long mode = CAM_READ_CACHE(pcdev, MODE);

I would make all variables, that are used specifically for various 
registers u32.

> +
> +	if (WARN_ON(!buf))
> +		return;
> +
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	/* don't enable end of frame interrupts before capture autostart */
> +	mode &= ~EN_V_DOWN;
> +#endif
> +	if (WARN_ON(mode & RAZ_FIFO))
> +		/*  clean up possibly insane reset condition */
> +		CAM_WRITE(pcdev, MODE, mode &= ~RAZ_FIFO);

It is usually better to avoid assigning variables inside other constructs, 
please split into two lines. Besides, in omap1_cam_probe() you initialise 
MODE to "THRESHOLD_LEVEL << THRESHOLD_SHIFT," i.e., RAZ_FIFO is cleared. 
So, don't think you need that test at all.

> +
> +	if (unlikely(ctrlclock & LCLK_EN))
> +		/* stop pixel clock before FIFO reset */
> +		CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock & ~LCLK_EN);
> +	/* reset FIFO */
> +	CAM_WRITE(pcdev, MODE, mode | RAZ_FIFO);
> +
> +	omap_start_dma(pcdev->dma_ch);
> +
> +	/* (re)enable pixel clock */
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock | LCLK_EN);
> +	/* release FIFO reset */
> +	CAM_WRITE(pcdev, MODE, mode);
> +
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +	try_next_sgbuf(pcdev->dma_ch, buf);
> +#endif
> +}
> +
> +static void suspend_capture(struct omap1_cam_dev *pcdev)
> +{
> +	unsigned long ctrlclock = CAM_READ_CACHE(pcdev, CTRLCLOCK);

u32

> +
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock & ~LCLK_EN);
> +	omap_stop_dma(pcdev->dma_ch);
> +}
> +
> +static void disable_capture(struct omap1_cam_dev *pcdev)
> +{
> +	unsigned long mode = CAM_READ_CACHE(pcdev, MODE);

u32 (etc.)

> +
> +	CAM_WRITE(pcdev, MODE, mode & ~(IRQ_MASK | DMA));
> +}
> +
> +static void omap1_videobuf_queue(struct videobuf_queue *vq,
> +						struct videobuf_buffer *vb)
> +{
> +	struct soc_camera_device *icd = vq->priv_data;
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +	struct omap1_cam_buf *buf;
> +	unsigned long mode;
> +
> +	list_add_tail(&vb->queue, &pcdev->capture);
> +	vb->state = VIDEOBUF_QUEUED;
> +
> +	if (pcdev->active)
> +		return;
> +
> +	WARN_ON(pcdev->ready);
> +
> +	buf = prepare_next_vb(pcdev);
> +	if (WARN_ON(!buf))
> +		return;
> +
> +	pcdev->active = buf;
> +	pcdev->ready = NULL;
> +
> +	dev_dbg(icd->dev.parent, "%s: capture not active, setup FIFO, start DMA"
> +			"\n", __func__);

No need to split "\n" to a new line, don't worry about > 80 characters...

> +	mode = CAM_READ_CACHE(pcdev, MODE) & (THRESHOLD_MASK | ORDERCAMD);
> +	mode |= EN_FIFO_FULL | DMA;
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	CAM_WRITE(pcdev, MODE, mode | EN_V_UP);
> +#else
> +	CAM_WRITE(pcdev, MODE, mode | EN_V_DOWN);
> +
> +	try_next_sgbuf(pcdev->dma_ch, buf);
> +#endif
> +	start_capture(pcdev);
> +}
> +
> +static void omap1_videobuf_release(struct videobuf_queue *vq,
> +				 struct videobuf_buffer *vb)
> +{
> +	struct omap1_cam_buf *buf =
> +			container_of(vb, struct omap1_cam_buf, vb);
> +	struct soc_camera_device *icd = vq->priv_data;
> +	struct device *dev = icd->dev.parent;
> +
> +	switch (vb->state) {
> +	case VIDEOBUF_DONE:
> +		dev_dbg(dev, "%s (done)\n", __func__);
> +		break;
> +	case VIDEOBUF_ACTIVE:
> +		dev_dbg(dev, "%s (active)\n", __func__);
> +		break;
> +	case VIDEOBUF_QUEUED:
> +		dev_dbg(dev, "%s (queued)\n", __func__);
> +		break;
> +	case VIDEOBUF_PREPARED:
> +		dev_dbg(dev, "%s (prepared)\n", __func__);
> +		break;
> +	default:
> +		dev_dbg(dev, "%s (unknown)\n", __func__);
> +		break;
> +	}
> +
> +	free_buffer(vq, buf);
> +}
> +
> +static void videobuf_done(struct omap1_cam_dev *pcdev,
> +		enum videobuf_state result)
> +{
> +	struct omap1_cam_buf *buf = pcdev->active;
> +	struct videobuf_buffer *vb;
> +	struct device *dev = pcdev->icd->dev.parent;
> +
> +	if (WARN_ON(!buf)) {
> +		suspend_capture(pcdev);
> +		disable_capture(pcdev);
> +		return;
> +	}
> +
> +	if (result == VIDEOBUF_ERROR)
> +		suspend_capture(pcdev);
> +
> +	vb = &buf->vb;
> +	if (waitqueue_active(&vb->done)) {

I'm not sure this is a good idea. Why are you reusing the buffer, if noone 
is waiting for it _now_? It can well be, that the task is doing something 
else atm. Like processing the previous frame. Or it has been preempted by 
another process, before it called poll() or select() on your device?

> +		if (!pcdev->ready && result != VIDEOBUF_ERROR)
> +			suspend_capture(pcdev);
> +		vb->state = result;
> +		do_gettimeofday(&vb->ts);
> +		vb->field_count++;

I don't think you're supposed to increment field_count if you've got a 
VIDEOBUF_ERROR.

> +		wake_up(&vb->done);
> +
> +		pcdev->active = buf = pcdev->ready;
> +		pcdev->ready = NULL;
> +
> +		if (!buf) {
> +			result = VIDEOBUF_ERROR;
> +			prepare_next_vb(pcdev);
> +
> +			pcdev->active = buf = pcdev->ready;
> +			pcdev->ready = NULL;
> +		}
> +	} else if (pcdev->ready) {
> +		dev_dbg(dev, "%s: nobody waiting on videobuf, swap with next\n",
> +				__func__);

Not sure this is a wise decision... If there are more buffers in the 
queue, they stay there waiting. Best remove this waitqueue_active() check 
entirely, just complete buffers and wake up the user regardless. If no 
more buffers - go to sleep.

> +		pcdev->active = pcdev->ready;
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +		buf->sgbuf = NULL;
> +#endif
> +		pcdev->ready = buf;
> +
> +		buf = pcdev->active;
> +	} else {
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +		dev_dbg(dev, "%s: nobody waiting on videobuf, reuse it\n",
> +				__func__);
> +#else
> +		if (result != VIDEOBUF_ERROR) {
> +			suspend_capture(pcdev);
> +			result = VIDEOBUF_ERROR;
> +		}
> +		prepare_next_vb(pcdev);
> +#endif
> +	}
> +
> +	if (!buf) {
> +		dev_dbg(dev, "%s: no more videobufs, stop capture\n", __func__);
> +		disable_capture(pcdev);
> +		return;
> +	}
> +
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +	if (result == VIDEOBUF_ERROR)
> +		buf->sgbuf = NULL;
> +
> +	try_next_sgbuf(pcdev->dma_ch, buf);
> +#endif
> +
> +	if (result == VIDEOBUF_ERROR) {
> +		dev_dbg(dev, "%s: videobuf error; reset FIFO, restart DMA\n",
> +				__func__);
> +		start_capture(pcdev);
> +	}

This all doesn't look quite right, but I'll wait for documentation, before 
commenting.

> +
> +	prepare_next_vb(pcdev);
> +}
> +
> +static void dma_isr(int channel, unsigned short status, void *data)
> +{
> +	struct omap1_cam_dev *pcdev = data;
> +	struct omap1_cam_buf *buf = pcdev->active;
> +	enum videobuf_state result;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&pcdev->lock, flags);
> +
> +	if (WARN_ON(!buf)) {
> +		suspend_capture(pcdev);
> +		disable_capture(pcdev);
> +		goto out;
> +	}
> +
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	/* videobuf complete, disable end of frame interrupt for this frame */
> +	CAM_WRITE(pcdev, MODE, CAM_READ_CACHE(pcdev, MODE) & ~EN_V_DOWN);
> +	result = VIDEOBUF_DONE;
> +#else
> +	if (buf->sgbuf) {
> +		/* current sglist not complete yet */
> +		try_next_sgbuf(pcdev->dma_ch, buf);
> +		if (buf->sgbuf)
> +			goto out;
> +
> +		if (buf->result != VIDEOBUF_ERROR) {
> +			buf = prepare_next_vb(pcdev);
> +			if (!buf)
> +				goto out;
> +
> +			try_next_sgbuf(pcdev->dma_ch, buf);
> +			goto out;
> +		}
> +	}
> +	/* end of videobuf */
> +	result = buf->result;
> +#endif
> +	videobuf_done(pcdev, result);
> +out:
> +	spin_unlock_irqrestore(&pcdev->lock, flags);
> +}
> +
> +static irqreturn_t cam_isr(int irq, void *data)
> +{
> +	struct omap1_cam_dev *pcdev = data;
> +	struct device *dev = pcdev->icd->dev.parent;
> +	struct omap1_cam_buf *buf = pcdev->active;
> +	unsigned long it_status;
> +	unsigned long flags;
> +
> +	it_status = CAM_READ(pcdev, IT_STATUS);
> +	if (!it_status)
> +		return IRQ_NONE;
> +
> +	spin_lock_irqsave(&pcdev->lock, flags);
> +
> +	if (WARN_ON(!buf)) {
> +		suspend_capture(pcdev);
> +		disable_capture(pcdev);
> +		goto out;
> +	}
> +
> +	if (unlikely(it_status & FIFO_FULL)) {
> +		dev_warn(dev, "%s: FIFO overflow\n", __func__);
> +
> +	} else if (it_status & V_DOWN) {
> +#ifdef CONFIG_VIDEO_OMAP1_SG
> +		/*
> +		 * if exactly 2 sgbufs of the next sglist has be used,
> +		 * then we are in sync
> +		 */

You mean the hardware is supposed to interrupt you after 2 buffers?

> +		if (buf && buf->sgcount == 2)
> +			goto out;
> +#endif
> +		dev_notice(dev, "%s: unexpected end of video frame\n",
> +				__func__);
> +
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	} else if (it_status & V_UP) {
> +		unsigned long mode = CAM_READ_CACHE(pcdev, MODE);
> +
> +		if (!(mode & EN_V_DOWN)) {
> +			/* enable end of frame interrupt for current videobuf */
> +			CAM_WRITE(pcdev, MODE, mode | EN_V_DOWN);
> +		}
> +		goto out;
> +#endif
> +
> +	} else {
> +		dev_warn(pcdev->soc_host.v4l2_dev.dev, "%s: "
> +				"unhandled camera interrupt, status == 0x%lx\n",
> +				__func__, it_status);
> +		goto out;
> +	}
> +
> +	videobuf_done(pcdev, VIDEOBUF_ERROR);
> +out:
> +	spin_unlock_irqrestore(&pcdev->lock, flags);
> +	return IRQ_HANDLED;
> +}
> +
> +static struct videobuf_queue_ops omap1_videobuf_ops = {
> +	.buf_setup	= omap1_videobuf_setup,
> +	.buf_prepare	= omap1_videobuf_prepare,
> +	.buf_queue	= omap1_videobuf_queue,
> +	.buf_release	= omap1_videobuf_release,
> +};
> +
> +
> +/*
> + * SOC Camera host operations
> + */
> +
> +static void sensor_reset(struct omap1_cam_dev *pcdev, bool reset)
> +{
> +	/* apply/release camera sensor reset if requested by platform data */
> +	if (pcdev->pflags & OMAP1_CAMERA_RST_HIGH)
> +		CAM_WRITE(pcdev, GPIO, reset);
> +	else if (pcdev->pflags & OMAP1_CAMERA_RST_LOW)
> +		CAM_WRITE(pcdev, GPIO, !reset);
> +}
> +
> +/*
> + * The following two functions absolutely depend on the fact, that
> + * there can be only one camera on OMAP1 camera sensor interface
> + */
> +static int omap1_cam_add_device(struct soc_camera_device *icd)
> +{
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +	unsigned int ctrlclock;

u32

> +	int ret = 0;
> +
> +	if (pcdev->icd) {
> +		ret = -EBUSY;
> +		goto ebusy;
> +	}
> +
> +	clk_enable(pcdev->clk);
> +
> +	/* setup sensor clock */
> +	ctrlclock = CAM_READ(pcdev, CTRLCLOCK);
> +	ctrlclock &= ~(CAMEXCLK_EN | MCLK_EN | DPLL_EN);
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock);
> +
> +	ctrlclock &= ~FOSCMOD_MASK;
> +	switch (pcdev->camexclk) {
> +	case CAM_EXCLK_6MHz:

just use constants for these

> +		ctrlclock |= CAMEXCLK_EN | FOSCMOD_6MHz;
> +		break;
> +	case CAM_EXCLK_8MHz:
> +		ctrlclock |= CAMEXCLK_EN | FOSCMOD_8MHz | DPLL_EN;
> +		break;
> +	case CAM_EXCLK_9_6MHz:
> +		ctrlclock |= CAMEXCLK_EN | FOSCMOD_9_6MHz | DPLL_EN;
> +		break;
> +	case CAM_EXCLK_12MHz:
> +		ctrlclock |= CAMEXCLK_EN | FOSCMOD_12MHz;
> +		break;
> +	case CAM_EXCLK_24MHz:
> +		ctrlclock |= CAMEXCLK_EN | FOSCMOD_24MHz | DPLL_EN;
> +	default:

This is the case of "Not providing sensor clock," do you still have to 
enable the clock at all below (MCLK_EN)?

> +		break;
> +	}
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock & ~DPLL_EN);
> +
> +	/* enable clock */
> +	ctrlclock |= MCLK_EN;
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock);
> +
> +	sensor_reset(pcdev, 0);

use "false" for the second parameter

> +
> +	pcdev->icd = icd;
> +
> +	dev_info(icd->dev.parent, "OMAP1 Camera driver attached to camera %d\n",
> +		 icd->devnum);
> +ebusy:
> +	return ret;
> +}
> +
> +static void omap1_cam_remove_device(struct soc_camera_device *icd)
> +{
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +	unsigned long ctrlclock;
> +
> +	BUG_ON(icd != pcdev->icd);
> +
> +	suspend_capture(pcdev);
> +	disable_capture(pcdev);
> +
> +	sensor_reset(pcdev, 1);
> +
> +	/* disable and release system clocks */
> +	ctrlclock = CAM_READ(pcdev, CTRLCLOCK);
> +	ctrlclock &= ~(MCLK_EN | DPLL_EN | CAMEXCLK_EN);
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock);
> +
> +	ctrlclock = (ctrlclock & ~FOSCMOD_MASK) | FOSCMOD_12MHz;
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock);
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock | MCLK_EN);
> +
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock & ~MCLK_EN);
> +
> +	clk_disable(pcdev->clk);
> +
> +	pcdev->icd = NULL;
> +
> +	dev_info(icd->dev.parent, "OMAP1 Camera driver detached from camera %d"
> +			"\n", icd->devnum);
> +}
> +
> +/* Duplicate standard formats based on host capability of byte swapping */
> +static const struct soc_mbus_pixelfmt omap1_cam_formats[] = {
> +	[V4L2_MBUS_FMT_YUYV8_2X8_BE] = {

You'll have to adjust these to the new names. Basically, for all YUYV8 and 
YVYU8 codes, "_LE" just gets dropped, and for "_BE" you swap 
chrominance-luminance pairs, i.e., UYVY8_2X8 instead of YUYV8_2X8_BE and 
VYUY8_2X8 instead of YVYU8_2X8_BE.

> +		.fourcc			= V4L2_PIX_FMT_YUYV,
> +		.name			= "YUYV",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_YVYU8_2X8_BE] = {
> +		.fourcc			= V4L2_PIX_FMT_YVYU,
> +		.name			= "YVYU",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_YUYV8_2X8_LE] = {
> +		.fourcc			= V4L2_PIX_FMT_UYVY,
> +		.name			= "UYVY",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_YVYU8_2X8_LE] = {
> +		.fourcc			= V4L2_PIX_FMT_VYUY,
> +		.name			= "VYUY",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE] = {
> +		.fourcc			= V4L2_PIX_FMT_RGB555,
> +		.name			= "RGB555",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_RGB555_2X8_PADHI_LE] = {
> +		.fourcc			= V4L2_PIX_FMT_RGB555X,
> +		.name			= "RGB555X",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_RGB565_2X8_BE] = {
> +		.fourcc			= V4L2_PIX_FMT_RGB565,
> +		.name			= "RGB565",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +	[V4L2_MBUS_FMT_RGB565_2X8_LE] = {
> +		.fourcc			= V4L2_PIX_FMT_RGB565X,
> +		.name			= "RGB565X",
> +		.bits_per_sample	= 8,
> +		.packing		= SOC_MBUS_PACKING_2X8_PADHI,
> +		.order			= SOC_MBUS_ORDER_BE,
> +	},
> +};
> +
> +static int omap1_cam_get_formats(struct soc_camera_device *icd,
> +		unsigned int idx, struct soc_camera_format_xlate *xlate)
> +{
> +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> +	struct device *dev = icd->dev.parent;
> +	int formats = 0, ret;
> +	enum v4l2_mbus_pixelcode code;
> +	const struct soc_mbus_pixelfmt *fmt;
> +
> +	ret = v4l2_subdev_call(sd, video, enum_mbus_fmt, idx, &code);
> +	if (ret < 0)
> +		/* No more formats */
> +		return 0;
> +
> +	fmt = soc_mbus_get_fmtdesc(code);
> +	if (!fmt) {
> +		dev_err(dev, "%s: invalid format code #%d: %d\n", __func__,
> +				idx, code);
> +		return 0;
> +	}
> +
> +	/* Check support for the requested bits-per-sample */
> +	if (fmt->bits_per_sample != 8)
> +		return 0;
> +
> +	switch (code) {
> +	case V4L2_MBUS_FMT_YUYV8_2X8_BE:
> +	case V4L2_MBUS_FMT_YVYU8_2X8_BE:
> +	case V4L2_MBUS_FMT_YUYV8_2X8_LE:
> +	case V4L2_MBUS_FMT_YVYU8_2X8_LE:
> +	case V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE:
> +	case V4L2_MBUS_FMT_RGB555_2X8_PADHI_LE:
> +	case V4L2_MBUS_FMT_RGB565_2X8_BE:
> +	case V4L2_MBUS_FMT_RGB565_2X8_LE:
> +		formats++;
> +		if (xlate) {
> +			xlate->host_fmt	= &omap1_cam_formats[code];
> +			xlate->code	= code;
> +			xlate++;
> +			dev_dbg(dev, "%s: providing format %s "
> +					"as byte swapped code #%d\n", __func__,
> +					omap1_cam_formats[code].name, code);
> +		}
> +	default:
> +		if (xlate)
> +			dev_dbg(dev, "%s: providing format %s "
> +					"in pass-through mode\n", __func__,
> +					fmt->name);
> +	}
> +	formats++;
> +	if (xlate) {
> +		xlate->host_fmt	= fmt;
> +		xlate->code	= code;
> +		xlate++;
> +	}
> +
> +	return formats;
> +}
> +
> +static int is_dma_aligned(s32 bytes_per_line, unsigned int height)

make it a bool

> +{
> +	int size = bytes_per_line * height;
> +
> +	return IS_ALIGNED(bytes_per_line, DMA_ELEMENT_SIZE) &&
> +			IS_ALIGNED(size, DMA_FRAME_SIZE * DMA_ELEMENT_SIZE);
> +}
> +
> +static int dma_align(int *width, int *height,
> +		const struct soc_mbus_pixelfmt *fmt, bool enlarge)
> +{
> +	s32 bytes_per_line = soc_mbus_bytes_per_line(*width, fmt);
> +
> +	if (bytes_per_line < 0)
> +		return bytes_per_line;
> +
> +	if (!is_dma_aligned(bytes_per_line, *height)) {
> +		unsigned int pxalign = __fls(bytes_per_line / *width);
> +		unsigned int salign  =
> +				DMA_FRAME_SHIFT + DMA_ELEMENT_SHIFT - pxalign;
> +		unsigned int incr    = enlarge << salign;
> +
> +		v4l_bound_align_image(width, DMA_ELEMENT_SIZE >> pxalign,
> +				*width + incr, DMA_ELEMENT_SHIFT - pxalign,

The above means, that lines must consist of an integer number of DMA 
elements, right? Is this really necessary?

> +				height, 1, *height + incr, 0, salign);
> +		return 0;
> +	}
> +	return 1;
> +}
> +
> +/* returns 1 on g_crop() success, 0 on cropcap() success, <0 on error */
> +static int get_crop(struct soc_camera_device *icd, struct v4l2_rect *rect)
> +{
> +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> +	struct device *dev = icd->dev.parent;
> +	struct v4l2_crop crop;
> +	int ret;
> +
> +	crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +	ret = v4l2_subdev_call(sd, video, g_crop, &crop);
> +	if (ret == -ENOIOCTLCMD) {
> +		struct v4l2_cropcap cc;
> +
> +		dev_dbg(dev, "%s: g_crop() missing, trying cropcap() instead"
> +				"\n", __func__);

Put "\n" back in the string

> +		cc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +		ret = v4l2_subdev_call(sd, video, cropcap, &cc);
> +		if (ret < 0)
> +			return ret;
> +		*rect = cc.defrect;
> +		return 0;
> +	} else if (ret < 0) {
> +		return ret;
> +	}
> +	*rect  = crop.c;

superfluous space

> +	return 1;
> +}
> +
> +/*
> + * returns 1 on g_mbus_fmt() or g_crop() success, 0 on cropcap() success,
> + * <0 on error
> + */
> +static int get_geometry(struct soc_camera_device *icd, struct v4l2_rect *rect,
> +		enum v4l2_mbus_pixelcode code)
> +{
> +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> +	struct device *dev = icd->dev.parent;
> +	struct v4l2_mbus_framefmt mf;
> +	int ret;
> +
> +	ret = v4l2_subdev_call(sd, video, g_mbus_fmt, &mf);
> +	if (ret == -ENOIOCTLCMD) {
> +		struct v4l2_rect c;
> +
> +		dev_dbg(dev, "%s: g_mbus_fmt() missing, trying g_crop() instead"
> +				"\n", __func__);

Put "\n" back in the string

> +		ret = get_crop(icd, &c);
> +		if (ret < 0)
> +			return ret;
> +		/* REVISIT:
> +		 * Should cropcap() obtained defrect reflect last s_crop()?
> +		 * Can we use it here for s_crop() result verification?
> +		 */

multiline comment style

> +		if (ret) {
> +			*rect = c;	/* use g_crop() result */
> +		} else {
> +			dev_warn(dev, "%s: current geometry not available\n",
> +					__func__);
> +			return 0;
> +		}
> +	} else if (ret < 0) {
> +		return ret;
> +	} else if (mf.code != code) {
> +		return -EINVAL;
> +	} else {
> +		rect->width  = mf.width;
> +		rect->height = mf.height;
> +	}
> +	return 1;
> +}
> +
> +#define subdev_call_with_sense(ret, function, args...) \
> +{ \
> +	struct soc_camera_sense sense = { \
> +		.master_clock		= pcdev->camexclk, \
> +		.pixel_clock_max	= 0, \
> +	}; \
> +\
> +	if (pcdev->pdata) \
> +		sense.pixel_clock_max = pcdev->pdata->lclk_khz_max * 1000; \
> +	icd->sense = &sense; \
> +	*(ret) = v4l2_subdev_call(sd, video, function, ##args); \
> +	icd->sense = NULL; \
> +\
> +	if (sense.flags & SOCAM_SENSE_PCLK_CHANGED) { \
> +		if (sense.pixel_clock > sense.pixel_clock_max) { \
> +			dev_err(dev, "%s: " \
> +				"pixel clock %lu set by the camera too high!" \
> +				"\n", __func__, sense.pixel_clock); \

"\n" back, please

> +			return -EIO; \
> +		} \
> +	} \
> +}

Ok, I'd prefer to follow some good-style rules here too. (1) please align 
your backslashes with TABs. (2) please, don't use implicitly passed 
variables, in this case "sd," "pcdev," "dev," and "icd." (3) since this is 
a macro, you don't need to pass ret as a pointer. (4) don't "return" from 
a macro - in your case it's enough to "ret = -EIO." Personally, I wouldn't 
worry about adding 4 more parameters to the macro. I would also remove 
"ret" from parameters and "return" it from the macro per

#define subdev_call_with_sense(pcdev, dev, icd, sd, function, args...)	\
({									\
	int __ret;							\
	...								\
	__ret = v4l2_subdev_call(sd, video, function, ##args);		\
	...								\
			__ret = -EINVAL;				\
	...								\
	__ret;								\
})

> +
> +static int omap1_cam_set_crop(struct soc_camera_device *icd,
> +			       struct v4l2_crop *crop)
> +{
> +	struct v4l2_rect *rect = &crop->c;
> +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +	struct device *dev = icd->dev.parent;
> +	s32 bytes_per_line;
> +	int ret;
> +
> +	ret = dma_align(&rect->width, &rect->height, icd->current_fmt->host_fmt,
> +			false);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: failed to align %ux%u %s with DMA\n",
> +				__func__, rect->width, rect->height,
> +				icd->current_fmt->host_fmt->name);
> +		return ret;
> +	}
> +
> +	subdev_call_with_sense(&ret, s_crop, crop);
> +	if (ret < 0) {
> +		dev_warn(dev, "%s: failed to crop to %ux%u@%u:%u\n", __func__,
> +			 rect->width, rect->height, rect->left, rect->top);
> +		return ret;
> +	}
> +
> +	ret = get_geometry(icd, rect, icd->current_fmt->code);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: get_geometry() failed\n", __func__);
> +		return ret;
> +	}
> +	if (!ret) {
> +		dev_warn(dev, "%s: unable to verify s_crop() results\n",
> +				__func__);
> +	}

Superfluous braces

> +
> +	bytes_per_line = soc_mbus_bytes_per_line(rect->width,
> +			icd->current_fmt->host_fmt);
> +	if (bytes_per_line < 0) {
> +		dev_err(dev, "%s: soc_mbus_bytes_per_line() failed\n",
> +				__func__);
> +		return bytes_per_line;
> +	}
> +
> +	ret = is_dma_aligned(bytes_per_line, rect->height);
> +	if (ret < 0) {

Doesn't look like this is possible.

> +		dev_err(dev, "%s: is_dma_aligned() failed\n", __func__);
> +		return ret;
> +	}
> +	if (!ret) {
> +		dev_err(dev, "%s: resulting geometry %dx%d not DMA aligned\n",
> +				__func__, rect->width, rect->height);
> +		return -EINVAL;
> +	}
> +
> +	icd->user_width	 = rect->width;
> +	icd->user_height = rect->height;

No, this is wrong. user_width and user_height are _user_ sizes, i.e., a 
result sensor cropping and scaling and host cropping and scaling. Whereas 
set_crop sets sensor input rectangle.

> +
> +	return ret;
> +}
> +
> +static int omap1_cam_set_fmt(struct soc_camera_device *icd,
> +			      struct v4l2_format *f)
> +{
> +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> +	const struct soc_camera_format_xlate *xlate;
> +	struct device *dev = icd->dev.parent;
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +	struct v4l2_pix_format *pix = &f->fmt.pix;
> +	struct v4l2_mbus_framefmt mf;
> +	struct v4l2_crop crop;
> +	struct v4l2_rect *rect = &crop.c;
> +	int bytes_per_line;
> +	int ret;
> +
> +	xlate = soc_camera_xlate_by_fourcc(icd, pix->pixelformat);
> +	if (!xlate) {
> +		dev_warn(dev, "%s: format %x not found\n", __func__,
> +				pix->pixelformat);
> +		return -EINVAL;
> +	}
> +
> +	bytes_per_line = soc_mbus_bytes_per_line(pix->width, xlate->host_fmt);
> +	if (bytes_per_line < 0) {
> +		dev_err(dev, "%s: soc_mbus_bytes_per_line() failed\n",
> +				__func__);
> +		return bytes_per_line;
> +	}
> +	if (pix->bytesperline && pix->bytesperline != bytes_per_line) {
> +		dev_err(dev, "%s: bytes per line mismatch\n", __func__);
> +		return -EINVAL;
> +	}
> +	ret = is_dma_aligned(bytes_per_line, pix->height);
> +	if (ret < 0) {

ditto - that's just a bool.

> +		dev_err(dev, "%s: is_dma_aligned() failed\n", __func__);
> +		return ret;
> +	}
> +	if (!ret) {
> +		dev_err(dev, "%s: image size %dx%d not DMA aligned\n",
> +				__func__, pix->width, pix->height);
> +		return -EINVAL;
> +	}
> +
> +	mf.width	= pix->width;
> +	mf.height	= pix->height;
> +	mf.field	= pix->field;
> +	mf.colorspace	= pix->colorspace;
> +	mf.code		= xlate->code;
> +
> +	subdev_call_with_sense(&ret, s_mbus_fmt, &mf);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: failed to set format\n", __func__);
> +		return ret;
> +	}
> +
> +	if (mf.code != xlate->code) {
> +		dev_err(dev, "%s: unexpected pixel code change\n", __func__);
> +		return -EINVAL;
> +	}
> +	icd->current_fmt = xlate;
> +
> +	pix->field	= mf.field;
> +	pix->colorspace	= mf.colorspace;
> +
> +	if (mf.width == pix->width && mf.height == pix->height)
> +		return 0;
> +
> +	dev_notice(dev, "%s: sensor geometry differs, trying to crop to %dx%d"
> +			"\n", __func__, pix->width, pix->height);

No, you shouldn't do this. It is normal, when S_FMT sets a format 
different from what the user has requested. Just leave it as is, only 
adjust if you cannot handle it or fail.

> +	crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +	ret = get_crop(icd, rect);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: get_crop() failed\n", __func__);
> +		return ret;
> +	}
> +
> +	rect->width  = pix->width;
> +	rect->height = pix->height;
> +
> +	subdev_call_with_sense(&ret, s_crop, &crop);
> +	if (ret < 0) {
> +		dev_warn(dev, "%s: failed to crop to %ux%u@%u:%u\n", __func__,
> +			 rect->width, rect->height, rect->left, rect->top);
> +		return ret;
> +	}
> +
> +	ret = get_geometry(icd, rect, xlate->code);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: get_geometry() failed\n", __func__);
> +		return ret;
> +	}
> +
> +	if (!ret) {
> +		dev_warn(dev, "%s: s_crop() results not verified\n", __func__);
> +		return 0;
> +	}
> +
> +	if (pix->width != rect->width || pix->height != rect->height) {
> +		dev_err(dev, "%s: tried to set %dx%d, got %dx%d\n", __func__,
> +				pix->width, pix->height,
> +				rect->width, rect->height);
> +		return -EINVAL;
> +	}

No, that's not an error. Just use whatever you managed to configure.

> +	return 0;
> +}
> +
> +static int omap1_cam_try_fmt(struct soc_camera_device *icd,
> +			      struct v4l2_format *f)
> +{
> +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> +	const struct soc_camera_format_xlate *xlate;
> +	struct device *dev = icd->dev.parent;
> +	struct v4l2_pix_format *pix = &f->fmt.pix;
> +	struct v4l2_mbus_framefmt mf, testmf;
> +	const struct soc_mbus_pixelfmt *fmt;
> +	int ret;
> +
> +	xlate = soc_camera_xlate_by_fourcc(icd, pix->pixelformat);
> +	if (!xlate) {
> +		dev_warn(dev, "%s: format %x not found\n", __func__,
> +				pix->pixelformat);
> +		return -EINVAL;
> +	}
> +
> +	fmt = xlate->host_fmt;
> +	ret = dma_align(&pix->width, &pix->height, fmt, true);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: failed to align %ux%u %s with DMA\n",
> +				__func__, pix->width, pix->height, fmt->name);
> +		return ret;
> +	}
> +
> +	mf.width      = pix->width;
> +	mf.height     = pix->height;
> +	mf.field      = pix->field;
> +	mf.colorspace = pix->colorspace;
> +	mf.code	      = xlate->code;
> +
> +	/* limit to sensor capabilities */
> +	ret = v4l2_subdev_call(sd, video, try_mbus_fmt, &mf);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: try_mbus_fmt() failed\n", __func__);
> +		return ret;
> +	}
> +
> +	pix->field	= mf.field;
> +	pix->colorspace	= mf.colorspace;
> +
> +	if (mf.width == pix->width && mf.height == pix->height &&
> +			mf.code == xlate->code)
> +		return 0;
> +
> +	dev_dbg(dev, "%s: geometry changed, recheck alignment\n", __func__);
> +	pix->width	  = mf.width;
> +	pix->height	  = mf.height;

This is what the sensor has returned, you put it back into the user frmat.

> +
> +	fmt = soc_mbus_get_fmtdesc(mf.code);
> +	ret = dma_align(&pix->width, &pix->height, fmt, false);

And you DMA-align those sizes.

> +	if (ret < 0) {
> +		dev_err(dev, "%s: failed to align %ux%u %s with DMA\n",
> +				__func__, pix->width, pix->height, fmt->name);
> +		return ret;
> +	}
> +	if (ret)
> +		return 0;
> +
> +	testmf.width	  = pix->width;
> +	testmf.height	  = pix->height;

And use them again for try_fmt

> +	testmf.field	  = mf.field;
> +	testmf.colorspace = mf.colorspace;
> +	testmf.code	  = mf.code;
> +
> +	ret = v4l2_subdev_call(sd, video, try_mbus_fmt, &testmf);
> +	if (ret < 0) {
> +		dev_err(dev, "%s: try_mbus_fmt() failed\n", __func__);
> +		return ret;
> +	}
> +
> +	if (testmf.code != mf.code || testmf.width != mf.width ||
> +			testmf.height != mf.height) {
> +		dev_err(dev, "%s: sensor format inconsistency, giving up\n",
> +				__func__);
> +		return -EINVAL;

As a general rule, try_fmt shouldn't fail... Only in very weird cases, 
really.

> +	}

And you verified, the sensor kept them.

> +	dev_notice(dev, "%s: "
> +		"sensor frame not DMA aligned, will try to crop from set_fmt()"

Hm? You did align them above? /me confused...

> +		"\n", __func__);
> +
> +	return 0;
> +}
> +
> +static void omap1_cam_init_videobuf(struct videobuf_queue *q,
> +				     struct soc_camera_device *icd)
> +{
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +
> +#ifndef CONFIG_VIDEO_OMAP1_SG
> +	videobuf_queue_dma_contig_init(q, &omap1_videobuf_ops, icd->dev.parent,
> +					&pcdev->lock,
> +					V4L2_BUF_TYPE_VIDEO_CAPTURE,
> +					V4L2_FIELD_NONE,
> +					sizeof(struct omap1_cam_buf),
> +					icd);
> +#else
> +	videobuf_queue_sg_init(q, &omap1_videobuf_ops, icd->dev.parent,
> +					&pcdev->lock,
> +					V4L2_BUF_TYPE_VIDEO_CAPTURE,
> +					V4L2_FIELD_NONE,
> +					sizeof(struct omap1_cam_buf),
> +					icd);
> +#endif
> +}
> +
> +static int omap1_cam_reqbufs(struct soc_camera_file *icf,
> +			      struct v4l2_requestbuffers *p)
> +{
> +	int i;
> +
> +	/*
> +	 * This is for locking debugging only. I removed spinlocks and now I
> +	 * check whether .prepare is ever called on a linked buffer, or whether
> +	 * a dma IRQ can occur for an in-work or unlinked buffer. Until now
> +	 * it hadn't triggered
> +	 */
> +	for (i = 0; i < p->count; i++) {
> +		struct omap1_cam_buf *buf = container_of(icf->vb_vidq.bufs[i],
> +						      struct omap1_cam_buf, vb);
> +		buf->inwork = 0;
> +		INIT_LIST_HEAD(&buf->vb.queue);
> +	}
> +
> +	return 0;
> +}
> +
> +static int omap1_cam_querycap(struct soc_camera_host *ici,
> +			       struct v4l2_capability *cap)
> +{
> +	/* cap->name is set by the friendly caller:-> */
> +	strlcpy(cap->card, "OMAP1 Camera", sizeof(cap->card));
> +	cap->version = VERSION_CODE;
> +	cap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
> +
> +	return 0;
> +}
> +
> +static int omap1_cam_set_bus_param(struct soc_camera_device *icd,
> +		__u32 pixfmt)
> +{
> +	struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
> +	struct omap1_cam_dev *pcdev = ici->priv;
> +	struct device *dev = icd->dev.parent;
> +	const struct soc_camera_format_xlate *xlate;
> +	const struct soc_mbus_pixelfmt *fmt;
> +	unsigned long camera_flags, common_flags;
> +	unsigned int ctrlclock, mode;
> +	int ret;
> +
> +	camera_flags = icd->ops->query_bus_param(icd);
> +
> +	common_flags = soc_camera_bus_param_compatible(camera_flags,
> +			SOCAM_BUS_FLAGS);
> +	if (!common_flags)
> +		return -EINVAL;
> +
> +	/* Make choices, possibly based on platform configuration */
> +	if ((common_flags & SOCAM_PCLK_SAMPLE_RISING) &&
> +			(common_flags & SOCAM_PCLK_SAMPLE_FALLING)) {
> +		if (!pcdev->pdata ||
> +				pcdev->pdata->flags & OMAP1_CAMERA_LCLK_RISING)
> +			common_flags &= ~SOCAM_PCLK_SAMPLE_FALLING;
> +		else
> +			common_flags &= ~SOCAM_PCLK_SAMPLE_RISING;
> +	}
> +
> +	ret = icd->ops->set_bus_param(icd, common_flags);
> +	if (ret < 0)
> +		return ret;
> +
> +	ctrlclock = CAM_READ_CACHE(pcdev, CTRLCLOCK);
> +	if (ctrlclock & LCLK_EN)
> +		CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock & ~LCLK_EN);
> +
> +	if (common_flags & SOCAM_PCLK_SAMPLE_RISING) {
> +		dev_dbg(dev, "CTRLCLOCK_REG |= POLCLK\n");
> +		ctrlclock |= POLCLK;
> +	} else {
> +		dev_dbg(dev, "CTRLCLOCK_REG &= ~POLCLK\n");
> +		ctrlclock &= ~POLCLK;
> +	}
> +	CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock & ~LCLK_EN);
> +
> +	if (ctrlclock & LCLK_EN)
> +		CAM_WRITE(pcdev, CTRLCLOCK, ctrlclock);
> +
> +	/* select bus endianess */
> +	xlate = soc_camera_xlate_by_fourcc(icd, pixfmt);
> +	fmt = xlate->host_fmt;
> +
> +	if (fmt->order == SOC_MBUS_ORDER_LE) {
> +		dev_dbg(dev, "MODE_REG &= ~ORDERCAMD\n");
> +		mode = CAM_READ(pcdev, MODE) & ~ORDERCAMD;
> +	} else {
> +		dev_dbg(dev, "MODE_REG |= ORDERCAMD\n");
> +		mode = CAM_READ(pcdev, MODE) | ORDERCAMD;
> +	}
> +	CAM_WRITE(pcdev, MODE, mode);
> +
> +	return 0;
> +}
> +
> +static unsigned int omap1_cam_poll(struct file *file, poll_table *pt)
> +{
> +	struct soc_camera_file *icf = file->private_data;
> +	struct omap1_cam_buf *buf;
> +
> +	buf = list_entry(icf->vb_vidq.stream.next, struct omap1_cam_buf,
> +			 vb.stream);
> +
> +	poll_wait(file, &buf->vb.done, pt);
> +
> +	if (buf->vb.state == VIDEOBUF_DONE ||
> +	    buf->vb.state == VIDEOBUF_ERROR)
> +		return POLLIN | POLLRDNORM;
> +
> +	return 0;
> +}
> +
> +static struct soc_camera_host_ops omap1_host_ops = {
> +	.owner		= THIS_MODULE,
> +	.add		= omap1_cam_add_device,
> +	.remove		= omap1_cam_remove_device,
> +	.get_formats	= omap1_cam_get_formats,
> +	.set_crop	= omap1_cam_set_crop,
> +	.set_fmt	= omap1_cam_set_fmt,
> +	.try_fmt	= omap1_cam_try_fmt,
> +	.init_videobuf	= omap1_cam_init_videobuf,
> +	.reqbufs	= omap1_cam_reqbufs,
> +	.querycap	= omap1_cam_querycap,
> +	.set_bus_param	= omap1_cam_set_bus_param,
> +	.poll		= omap1_cam_poll,
> +};
> +
> +static int __init omap1_cam_probe(struct platform_device *pdev)
> +{
> +	struct omap1_cam_dev *pcdev;
> +	struct resource *res;
> +	struct clk *clk;
> +	void __iomem *base;
> +	unsigned int irq;
> +	int err = 0;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	irq = platform_get_irq(pdev, 0);
> +	if (!res || (int)irq <= 0) {
> +		err = -ENODEV;
> +		goto exit;
> +	}
> +
> +	clk = clk_get(&pdev->dev, "armper_ck");
> +	if (IS_ERR(clk)) {
> +		err = PTR_ERR(clk);
> +		goto exit;
> +	}
> +
> +	pcdev = kzalloc(sizeof(*pcdev), GFP_KERNEL);
> +	if (!pcdev) {
> +		dev_err(&pdev->dev, "Could not allocate pcdev\n");
> +		err = -ENOMEM;
> +		goto exit_put_clk;
> +	}
> +
> +	pcdev->res = res;
> +	pcdev->clk = clk;
> +
> +	pcdev->pdata = pdev->dev.platform_data;
> +	pcdev->pflags = pcdev->pdata->flags;
> +
> +	if (pcdev->pdata)
> +		pcdev->camexclk = pcdev->pdata->camexclk_khz * 1000;
> +
> +	switch (pcdev->camexclk) {
> +	case CAM_EXCLK_6MHz:
> +	case CAM_EXCLK_8MHz:
> +	case CAM_EXCLK_9_6MHz:
> +	case CAM_EXCLK_12MHz:
> +	case CAM_EXCLK_24MHz:
> +		break;
> +	default:
> +		dev_warn(&pdev->dev,
> +				"Incorrect sensor clock frequency %ld kHz, "
> +				"should be one of 0, 6, 8, 9.6, 12 or 24 MHz, "
> +				"please correct your platform data\n",
> +				pcdev->pdata->camexclk_khz);
> +		pcdev->camexclk = 0;
> +	case 0:
> +		dev_info(&pdev->dev,
> +				"Not providing sensor clock\n");
> +	}
> +
> +	INIT_LIST_HEAD(&pcdev->capture);
> +	spin_lock_init(&pcdev->lock);
> +
> +	/*
> +	 * Request the region.
> +	 */
> +	if (!request_mem_region(res->start, resource_size(res), DRIVER_NAME)) {
> +		err = -EBUSY;
> +		goto exit_kfree;
> +	}
> +
> +	base = ioremap(res->start, resource_size(res));
> +	if (!base) {
> +		err = -ENOMEM;
> +		goto exit_release;
> +	}
> +	pcdev->irq = irq;
> +	pcdev->base = base;
> +
> +	/* apply reset to camera sensor if requested by platform data */
> +	if (pcdev->pflags & OMAP1_CAMERA_RST_HIGH)
> +		CAM_WRITE(pcdev, GPIO, 0x1);
> +	else if (pcdev->pflags & OMAP1_CAMERA_RST_LOW)
> +		CAM_WRITE(pcdev, GPIO, 0x0);

Why not use sensor_reset()?

> +
> +	err = omap_request_dma(OMAP_DMA_CAMERA_IF_RX, DRIVER_NAME,
> +			dma_isr, (void *)pcdev, &pcdev->dma_ch);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "Can't request DMA for OMAP1 Camera\n");
> +		err = -EBUSY;
> +		goto exit_iounmap;
> +	}
> +	dev_dbg(&pdev->dev, "got DMA channel %d\n", pcdev->dma_ch);
> +
> +	/* preconfigure DMA */
> +	omap_set_dma_src_params(pcdev->dma_ch, OMAP_DMA_PORT_TIPB,
> +			OMAP_DMA_AMODE_CONSTANT, res->start + REG_CAMDATA,
> +			0, 0);
> +	omap_set_dma_dest_burst_mode(pcdev->dma_ch, OMAP_DMA_DATA_BURST_4);
> +	/* setup DMA autoinitialization */
> +	omap_dma_link_lch(pcdev->dma_ch, pcdev->dma_ch);
> +
> +	CAM_WRITE(pcdev, MODE, THRESHOLD_LEVEL << THRESHOLD_SHIFT);
> +
> +	err = request_irq(pcdev->irq, cam_isr, 0, DRIVER_NAME, pcdev);
> +	if (err) {
> +		dev_err(&pdev->dev, "Camera interrupt register failed\n");
> +		goto exit_free_dma;
> +	}
> +
> +	pcdev->soc_host.drv_name	= DRIVER_NAME;
> +	pcdev->soc_host.ops		= &omap1_host_ops;
> +	pcdev->soc_host.priv		= pcdev;
> +	pcdev->soc_host.v4l2_dev.dev	= &pdev->dev;
> +	pcdev->soc_host.nr		= pdev->id;
> +
> +	err = soc_camera_host_register(&pcdev->soc_host);
> +	if (err)
> +		goto exit_free_irq;
> +
> +	dev_info(&pdev->dev, "OMAP1 Camera Interface driver loaded\n");
> +
> +	return 0;
> +
> +exit_free_irq:
> +	free_irq(pcdev->irq, pcdev);
> +exit_free_dma:
> +	omap_free_dma(pcdev->dma_ch);
> +exit_iounmap:
> +	iounmap(base);
> +exit_release:
> +	release_mem_region(res->start, resource_size(res));
> +exit_kfree:
> +	kfree(pcdev);
> +exit_put_clk:
> +	clk_put(clk);
> +exit:
> +	return err;
> +}
> +
> +static int __exit omap1_cam_remove(struct platform_device *pdev)
> +{
> +	struct soc_camera_host *soc_host = to_soc_camera_host(&pdev->dev);
> +	struct omap1_cam_dev *pcdev = container_of(soc_host,
> +					struct omap1_cam_dev, soc_host);
> +	struct resource *res;
> +
> +	soc_camera_host_unregister(soc_host);
> +
> +	free_irq(pcdev->irq, pcdev);
> +
> +	omap_free_dma(pcdev->dma_ch);

It is probably safer to first shut down the hardware, and only then 
unconfigure software. So, free_irq and free_dma should go first, I think.

> +
> +	iounmap(pcdev->base);
> +
> +	res = pcdev->res;
> +	release_mem_region(res->start, resource_size(res));
> +
> +	kfree(pcdev);
> +
> +	clk_put(pcdev->clk);
> +
> +	dev_info(&pdev->dev, "OMAP1 Camera Interface driver unloaded\n");
> +
> +	return 0;
> +}
> +
> +static struct platform_driver omap1_cam_driver = {
> +	.driver		= {
> +		.name	= DRIVER_NAME,
> +	},
> +	.probe		= omap1_cam_probe,
> +	.remove		= __exit_p(omap1_cam_remove),
> +};
> +
> +static int __init omap1_cam_init(void)
> +{
> +	return platform_driver_register(&omap1_cam_driver);
> +}
> +
> +static void __exit omap1_cam_exit(void)
> +{
> +	platform_driver_unregister(&omap1_cam_driver);
> +}
> +
> +module_init(omap1_cam_init);
> +module_exit(omap1_cam_exit);
> +
> +MODULE_DESCRIPTION("OMAP1 Camera Interface driver");
> +MODULE_AUTHOR("Janusz Krzysztofik <jkrzyszt at tis.icnet.pl>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> 

Other patch reviews to follow...

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/



More information about the e3-hacking mailing list