On Sun, 18 Jul 2010, Janusz Krzysztofik wrote:

> This patch provides a V4L2 SoC Camera driver for OV6650 camera sensor, found 
> on OMAP1 SoC based Amstrad Delta videophone.

Have you also had a look at drivers/media/video/gspca/sonixb.c - in also 
supports ov6650 among other sensors.

> Since I have no experience with camera sensors, and the sensor documentation 
> I 
> was able to find was not very comprehensive, I left most settings at their 
> default (reset) values, except for:
> - those required for proper mediabus parameters and picture format setup,
> - those used by controls.
> Resulting picture quality is far from perfect, but better than nothing.
> 
> In order to be able to get / set the sensor frame rate from userspace, I 
> decided to provide two not yet SoC camera supported operations, g_parm and 
> s_parm. These can be used after applying patch 4/6 from this series, 
> "SoC Camera: add support for g_parm / s_parm operations".
> 
> Created and tested against linux-2.6.35-rc3 on Amstrad Delta.
> 
> Signed-off-by: Janusz Krzysztofik <jkrzy...@tis.icnet.pl>
> ---
>  drivers/media/video/Kconfig     |    6
>  drivers/media/video/Makefile    |    1
>  drivers/media/video/ov6650.c    | 1336 
> ++++++++++++++++++++++++++++++++++++++++
>  include/media/v4l2-chip-ident.h |    1
>  4 files changed, 1344 insertions(+)
> 
> --- 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
> @@ -913,6 +913,12 @@ config SOC_CAMERA_PLATFORM
>       help
>         This is a generic SoC camera platform driver, useful for testing
>  
> +config SOC_CAMERA_OV6650
> +     tristate "ov6650 sensor support"
> +     depends on SOC_CAMERA && I2C
> +     help
> +       This is a V4L2 SoC camera driver for the OmniVision OV6650 sensor
> +
>  config SOC_CAMERA_OV772X
>       tristate "ov772x camera support"
>       depends on SOC_CAMERA && I2C
> --- 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
> @@ -79,6 +79,7 @@ obj-$(CONFIG_SOC_CAMERA_MT9M111)    += mt9m
>  obj-$(CONFIG_SOC_CAMERA_MT9T031)     += mt9t031.o
>  obj-$(CONFIG_SOC_CAMERA_MT9T112)     += mt9t112.o
>  obj-$(CONFIG_SOC_CAMERA_MT9V022)     += mt9v022.o
> +obj-$(CONFIG_SOC_CAMERA_OV6650)              += ov6650.o
>  obj-$(CONFIG_SOC_CAMERA_OV772X)              += ov772x.o
>  obj-$(CONFIG_SOC_CAMERA_OV9640)              += ov9640.o
>  obj-$(CONFIG_SOC_CAMERA_RJ54N1)              += rj54n1cb0c.o
> --- linux-2.6.35-rc3.orig/drivers/media/video/ov6650.c        1970-01-01 
> 01:00:00.000000000 +0100
> +++ linux-2.6.35-rc3/drivers/media/video/ov6650.c     2010-07-18 
> 02:06:22.000000000 +0200
> @@ -0,0 +1,1336 @@
> +/*
> + * V4L2 SoC Camera driver for OmniVision OV6650 Camera Sensor
> + *
> + * Copyright (C) 2010 Janusz Krzysztofik <jkrzy...@tis.icnet.pl>
> + *
> + * Based on OmniVision OV96xx Camera Driver
> + * Copyright (C) 2009 Marek Vasut <marek.va...@gmail.com>
> + *
> + * Based on ov772x camera driver:
> + * Copyright (C) 2008 Renesas Solutions Corp.
> + * Kuninori Morimoto <morimoto.kunin...@renesas.com>
> + *
> + * Based on ov7670 and soc_camera_platform driver,
> + * Copyright 2006-7 Jonathan Corbet <cor...@lwn.net>
> + * Copyright (C) 2008 Magnus Damm
> + * Copyright (C) 2008, Guennadi Liakhovetski <ker...@pengutronix.de>
> + *
> + * Hardware specific bits initialy based on former work by Matt Callow
> + * drivers/media/video/omap/sensor_ov6650.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/i2c.h>
> +#include <linux/slab.h>
> +#include <linux/delay.h>
> +#include <media/v4l2-chip-ident.h>
> +#include <media/soc_camera.h>

Please, sort headers alphabetically (media/ and linux/ separately, of 
course).

> +
> +
> +/* Register definitions */
> +#define      REG_GAIN                0x00    /* range 00 - 3F */
> +#define      REG_BLUE                0x01
> +#define      REG_RED                 0x02
> +#define      REG_SAT                 0x03    /* [7:4] saturation [0:3] 
> reserved */
> +#define      REG_HUE                 0x04    /* [7:6] rsrvd [5] hue en [4:0] 
> hue */
> +
> +#define      REG_BRT                 0x06
> +
> +#define      REG_PIDH                0x0a
> +#define      REG_PIDL                0x0b
> +
> +#define      REG_AECH                0x10
> +#define      REG_CLKRC               0x11    /* Data Format and Internal 
> Clock */
> +                                     /* [7:6] Input system clock (MHz)*/
> +                                     /*   00=8, 01=12, 10=16, 11=24 */
> +                                     /* [5:0]: Internal Clock Pre-Scaler */
> +#define      REG_COMA                0x12    /* [7] Reset */
> +#define      REG_COMB                0x13
> +#define      REG_COMC                0x14
> +#define      REG_COMD                0x15
> +#define REG_COML             0x16

You used TAB in most defines and a space in this one and a few ones below. 
Please, use the same for all (I personally would just use a space).

> +#define      REG_HSTRT               0x17
> +#define      REG_HSTOP               0x18
> +#define      REG_VSTRT               0x19
> +#define      REG_VSTOP               0x1a
> +#define      REG_PSHFT               0x1b
> +#define      REG_MIDH                0x1c
> +#define      REG_MIDL                0x1d
> +#define      REG_HSYNS               0x1e
> +#define      REG_HSYNE               0x1f
> +#define      REG_COME                0x20
> +#define      REG_YOFF                0x21
> +#define      REG_UOFF                0x22
> +#define      REG_VOFF                0x23
> +#define      REG_AEW                 0x24
> +#define      REG_AEB                 0x25
> +#define      REG_COMF                0x26
> +#define      REG_COMG                0x27
> +#define      REG_COMH                0x28
> +#define REG_COMI             0x29
> +
> +#define      REG_FRARL               0x2b
> +#define      REG_COMJ                0x2c
> +#define      REG_COMK                0x2d
> +#define      REG_AVGY                0x2e
> +#define      REG_REF0                0x2f
> +#define      REG_REF1                0x30
> +#define      REG_REF2                0x31
> +#define      REG_FRAJH               0x32
> +#define      REG_FRAJL               0x33
> +#define      REG_FACT                0x34
> +#define REG_L1AEC            0x35
> +#define REG_AVGU             0x36
> +#define      REG_AVGV                0x37
> +
> +#define      REG_SPCB                0x60
> +#define      REG_SPCC                0x61
> +#define      REG_GAM1                0x62
> +#define      REG_GAM2                0x63
> +#define      REG_GAM3                0x64
> +#define      REG_SPCD                0x65
> +
> +#define      REG_SPCE                0x68
> +#define      REG_ADCL                0x69
> +
> +#define      REG_RMCO                0x6c
> +#define      REG_GMCO                0x6d
> +#define      REG_BMCO                0x6e
> +
> +#define NUM_REGS             (REG_BMCO + 1)

NUM_REGS is unused, don't need to define it.

> +
> +
> +/* Register bits, values, etc. */
> +#define OV6650_PIDH          0x66    /* high byte of product ID number */
> +#define OV6650_PIDL          0x50    /* low byte of product ID number */
> +#define OV6650_MIDH          0x7F    /* high byte of mfg ID */
> +#define OV6650_MIDL          0xA2    /* low byte of mfg ID */
> +
> +#define DEF_GAIN             0x00
> +#define DEF_BLUE             0x80
> +#define DEF_RED                      0x80
> +
> +#define SAT_SHIFT            4
> +#define SAT_MASK             0xf
> +#define SET_SAT(x)           (((x) & SAT_MASK) << SAT_SHIFT)

Nitpicking, but I would

+#define SAT_SHIFT              4
+#define SAT_MASK               0xf0
+#define SET_SAT(x)             (((x) << SAT_SHIFT) & SAT_MASK)

Advantage: your SAT_MASK is already correctly shifted, so, you don't have 
to you SET_SAT(SAT_MASK) to get to the register value.

> +
> +#define HUE_EN                       BIT(5)

You have to #include <linux/bitops.h> for the BIT() macro

> +#define HUE_MASK             0x1f
> +#define DEF_HUE                      0x10
> +#define SET_HUE(x)           ((x) == DEF_HUE ? (x) : \
> +                                             HUE_EN | ((x) & HUE_MASK))
> +
> +#define DEF_AECH             0x4D
> +
> +#define      CLKRC_6MHz              0x00
> +#define      CLKRC_12MHz             0x40
> +#define      CLKRC_16MHz             0x80
> +#define      CLKRC_24MHz             0xc0
> +#define      CLKRC_DIV_MASK          0x3f
> +#define      GET_CLKRC_DIV(x)        (((x) & CLKRC_DIV_MASK) + 1)
> +
> +#define COMA_RESET           BIT(7)
> +#define COMA_QCIF            BIT(5)
> +#define COMA_RAW_RGB         BIT(4)
> +#define COMA_RGB             BIT(3)
> +#define COMA_BW                      BIT(2)
> +#define COMA_WORD_SWAP               BIT(1)
> +#define COMA_BYTE_SWAP               BIT(0)
> +#define DEF_COMA             0x00
> +
> +#define      COMB_FLIP_V             BIT(7)
> +#define      COMB_FLIP_H             BIT(5)
> +#define COMB_AWB             BIT(2)
> +#define COMB_AGC             BIT(1)
> +#define COMB_AEC             BIT(0)
> +
> +#define COML_ONE_CHANNEL     BIT(7)
> +
> +#define DEF_HSTRT            0x24
> +#define DEF_HSTOP            0xd4
> +#define DEF_VSTRT            0x04
> +#define DEF_VSTOP            0x94
> +
> +#define COMF_HREF_LOW                BIT(4)
> +
> +#define COMJ_PCLK_RISING     BIT(4)
> +#define COMJ_VSYNC_HIGH              BIT(0)
> +
> +/* supported resolutions */
> +#define W_QCIF                       (DEF_HSTOP - DEF_HSTRT)
> +#define W_CIF                        (W_QCIF << 1)
> +#define H_QCIF                       (DEF_VSTOP - DEF_VSTRT)
> +#define H_CIF                        (H_QCIF << 1)
> +
> +#define FRAME_RATE_MAX               30
> +
> +
> +struct ov6650_reg {
> +     u8      reg;
> +     u8      val;
> +};
> +
> +struct ov6650 {
> +     struct v4l2_subdev      subdev;
> +
> +     int                     gain;
> +     int                     blue;
> +     int                     red;
> +     int                     saturation;
> +     int                     hue;
> +     int                     brightness;
> +     int                     exposure;
> +     int                     gamma;
> +     bool                    vflip;
> +     bool                    hflip;
> +     bool                    awb;
> +     bool                    agc;
> +     int                     aec;
> +     bool                    hue_auto;
> +     bool                    qcif;
> +     unsigned long           pclk_max;       /* from resolution and format */
> +     unsigned long           pclk_limit;     /* from host */
> +     struct v4l2_fract       timeperframe;   /* as requested with s_parm */
> +};
> +
> +
> +/* default register setup */
> +static const struct ov6650_reg ov6650_regs_dflt[] = {
> +     { REG_COMA,     DEF_COMA },     /* ~COMA_RESET */
> +};
> +
> +static enum v4l2_mbus_pixelcode ov6650_codes[] = {
> +     V4L2_MBUS_FMT_YUYV8_2X8_LE,
> +     V4L2_MBUS_FMT_YUYV8_2X8_BE,
> +     V4L2_MBUS_FMT_YVYU8_2X8_LE,
> +     V4L2_MBUS_FMT_YVYU8_2X8_BE,
> +     V4L2_MBUS_FMT_SBGGR8_1X8,
> +     V4L2_MBUS_FMT_GREY8_1X8,
> +};
> +
> +static const struct v4l2_queryctrl ov6650_controls[] = {
> +     {
> +             .id             = V4L2_CID_AUTOGAIN,
> +             .type           = V4L2_CTRL_TYPE_BOOLEAN,
> +             .name           = "AGC",
> +             .minimum        = 0,
> +             .maximum        = 1,
> +             .step           = 1,
> +             .default_value  = 1,
> +     },
> +     {
> +             .id             = V4L2_CID_GAIN,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Gain",
> +             .minimum        = 0,
> +             .maximum        = 0x3f,
> +             .step           = 1,
> +             .default_value  = DEF_GAIN,
> +     },
> +     {
> +             .id             = V4L2_CID_AUTO_WHITE_BALANCE,
> +             .type           = V4L2_CTRL_TYPE_BOOLEAN,
> +             .name           = "AWB",
> +             .minimum        = 0,
> +             .maximum        = 1,
> +             .step           = 1,
> +             .default_value  = 1,
> +     },
> +     {
> +             .id             = V4L2_CID_BLUE_BALANCE,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Blue",
> +             .minimum        = 0,
> +             .maximum        = 0xff,
> +             .step           = 1,
> +             .default_value  = DEF_BLUE,
> +     },
> +     {
> +             .id             = V4L2_CID_RED_BALANCE,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Red",
> +             .minimum        = 0,
> +             .maximum        = 0xff,
> +             .step           = 1,
> +             .default_value  = DEF_RED,
> +     },
> +     {
> +             .id             = V4L2_CID_SATURATION,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Saturation",
> +             .minimum        = 0,
> +             .maximum        = 0xf,
> +             .step           = 1,
> +             .default_value  = 0x8,
> +     },
> +     {
> +             .id             = V4L2_CID_HUE_AUTO,
> +             .type           = V4L2_CTRL_TYPE_BOOLEAN,
> +             .name           = "Auto Hue",
> +             .minimum        = 0,
> +             .maximum        = 1,
> +             .step           = 1,
> +             .default_value  = 1,
> +     },
> +     {
> +             .id             = V4L2_CID_HUE,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Hue",
> +             .minimum        = 0,
> +             .maximum        = 0x1f,
> +             .step           = 1,
> +             .default_value  = DEF_HUE,
> +     },
> +     {
> +             .id             = V4L2_CID_BRIGHTNESS,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Brightness",
> +             .minimum        = 0,
> +             .maximum        = 0xff,
> +             .step           = 1,
> +             .default_value  = 0x80,
> +     },
> +     {
> +             .id             = V4L2_CID_EXPOSURE_AUTO,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "AEC",
> +             .minimum        = 0,
> +             .maximum        = 3,
> +             .step           = 1,
> +             .default_value  = 0,
> +     },
> +     {
> +             .id             = V4L2_CID_EXPOSURE,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Exposure",
> +             .minimum        = 0,
> +             .maximum        = 0xff,
> +             .step           = 1,
> +             .default_value  = DEF_AECH,
> +     },
> +     {
> +             .id             = V4L2_CID_GAMMA,
> +             .type           = V4L2_CTRL_TYPE_INTEGER,
> +             .name           = "Gamma",
> +             .minimum        = 0,
> +             .maximum        = 0xff,
> +             .step           = 1,
> +             .default_value  = 0x12,
> +     },
> +     {
> +             .id             = V4L2_CID_VFLIP,
> +             .type           = V4L2_CTRL_TYPE_BOOLEAN,
> +             .name           = "Flip Vertically",
> +             .minimum        = 0,
> +             .maximum        = 1,
> +             .step           = 1,
> +             .default_value  = 0,
> +     },
> +     {
> +             .id             = V4L2_CID_HFLIP,
> +             .type           = V4L2_CTRL_TYPE_BOOLEAN,
> +             .name           = "Flip Horizontally",
> +             .minimum        = 0,
> +             .maximum        = 1,
> +             .step           = 1,
> +             .default_value  = 0,
> +     },
> +};
> +
> +/* read a register */
> +static int ov6650_reg_read(struct i2c_client *client, u8 reg, u8 *val)
> +{
> +     int ret;
> +     u8 data = reg;
> +     struct i2c_msg msg = {
> +             .addr   = client->addr,
> +             .flags  = 0,
> +             .len    = 1,
> +             .buf    = &data,
> +     };
> +
> +     ret = i2c_transfer(client->adapter, &msg, 1);
> +     if (ret < 0)
> +             goto err;
> +
> +     msg.flags = I2C_M_RD;
> +     ret = i2c_transfer(client->adapter, &msg, 1);
> +     if (ret < 0)
> +             goto err;
> +
> +     *val = data;
> +     return 0;
> +
> +err:
> +     dev_err(&client->dev, "Failed reading register 0x%02x!\n", reg);
> +     return ret;
> +}
> +
> +/* write a register */
> +static int ov6650_reg_write(struct i2c_client *client, u8 reg, u8 val)
> +{
> +     int ret;
> +     u8 _val;
> +     unsigned char data[2] = { reg, val };
> +     struct i2c_msg msg = {
> +             .addr   = client->addr,
> +             .flags  = 0,
> +             .len    = 2,
> +             .buf    = data,
> +     };
> +
> +     ret = i2c_transfer(client->adapter, &msg, 1);
> +     if (ret < 0) {
> +             dev_err(&client->dev, "Failed writing register 0x%02x!\n", reg);
> +             return ret;
> +     }
> +     msleep(1);

Hm, interesting... Is this really needed?

> +
> +     /* we have to read the register back ... no idea why, maybe HW bug */
> +     ret = ov6650_reg_read(client, reg, &_val);

You can also use "val" - it is not needed any more - and drop "_val."

> +     if (ret)
> +             dev_err(&client->dev,
> +                     "Failed reading back register 0x%02x!\n", reg);
> +
> +     return 0;
> +}
> +
> +
> +/* Read a register, alter its bits, write it back */
> +static int ov6650_reg_rmw(struct i2c_client *client, u8 reg, u8 set, u8 mask)
> +{
> +     u8 val;
> +     int ret;
> +
> +     ret = ov6650_reg_read(client, reg, &val);
> +     if (ret) {
> +             dev_err(&client->dev,
> +                     "[Read]-Modify-Write of register %02x failed!\n", reg);
> +             return val;

You mean "return ret"

> +     }
> +
> +     val &= ~mask;
> +     val |= set;
> +
> +     ret = ov6650_reg_write(client, reg, val);
> +     if (ret)
> +             dev_err(&client->dev,
> +                     "Read-Modify-[Write] of register %02x failed!\n", reg);
> +
> +     return ret;
> +}
> +
> +/* Soft reset the camera. This has nothing to do with the RESET pin! */
> +static int ov6650_reset(struct i2c_client *client)
> +{
> +     int ret;
> +
> +     dev_dbg(&client->dev, "reset\n");
> +
> +     ret = ov6650_reg_rmw(client, REG_COMA, COMA_RESET, 0);
> +     if (ret)
> +             dev_err(&client->dev,
> +                     "An error occured while entering soft reset!\n");
> +
> +     return ret;
> +}
> +
> +static struct ov6650 *to_ov6650(const struct i2c_client *client)
> +{
> +     return container_of(i2c_get_clientdata(client), struct ov6650, subdev);
> +}
> +
> +/* Start/Stop streaming from the device */
> +static int ov6650_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +     return 0;
> +}
> +
> +/* Alter bus settings on camera side */
> +static int ov6650_set_bus_param(struct soc_camera_device *icd,
> +                             unsigned long flags)
> +{
> +     struct soc_camera_link *icl = to_soc_camera_link(icd);
> +     struct i2c_client *client = to_i2c_client(to_soc_camera_control(icd));
> +     int ret;
> +
> +     flags = soc_camera_apply_sensor_flags(icl, flags);
> +
> +     if (flags & SOCAM_PCLK_SAMPLE_RISING)
> +             ret = ov6650_reg_rmw(client, REG_COMJ, COMJ_PCLK_RISING, 0);
> +     else
> +             ret = ov6650_reg_rmw(client, REG_COMJ, 0, COMJ_PCLK_RISING);
> +     if (ret)
> +             goto out;
> +
> +     if (flags & SOCAM_HSYNC_ACTIVE_LOW)
> +             ret = ov6650_reg_rmw(client, REG_COMF, COMF_HREF_LOW, 0);
> +     else
> +             ret = ov6650_reg_rmw(client, REG_COMF, 0, COMF_HREF_LOW);
> +     if (ret)
> +             goto out;
> +
> +     if (flags & SOCAM_VSYNC_ACTIVE_HIGH)
> +             ret = ov6650_reg_rmw(client, REG_COMJ, COMJ_VSYNC_HIGH, 0);
> +     else
> +             ret = ov6650_reg_rmw(client, REG_COMJ, 0, COMJ_VSYNC_HIGH);
> +out:
> +     return ret;
> +}
> +
> +/* Request bus settings on camera side */
> +static unsigned long ov6650_query_bus_param(struct soc_camera_device *icd)
> +{
> +     struct soc_camera_link *icl = to_soc_camera_link(icd);
> +
> +     unsigned long flags = SOCAM_MASTER | \
> +             SOCAM_PCLK_SAMPLE_RISING | SOCAM_PCLK_SAMPLE_FALLING | \
> +             SOCAM_HSYNC_ACTIVE_HIGH | SOCAM_HSYNC_ACTIVE_LOW | \
> +             SOCAM_VSYNC_ACTIVE_HIGH | SOCAM_VSYNC_ACTIVE_LOW | \
> +             SOCAM_DATA_ACTIVE_HIGH | SOCAM_DATAWIDTH_8;
> +
> +     return soc_camera_apply_sensor_flags(icl, flags);
> +}
> +
> +/* Get status of additional camera capabilities */
> +static int ov6650_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct ov6650 *priv = to_ov6650(client);
> +     uint8_t reg;
> +     int ret = 0;
> +
> +     switch (ctrl->id) {
> +     case V4L2_CID_AUTOGAIN:
> +             ctrl->value = priv->agc;
> +             break;
> +     case V4L2_CID_GAIN:
> +             if (priv->agc) {
> +                     ret = ov6650_reg_read(client, REG_GAIN, &reg);
> +                     ctrl->value = reg;
> +             } else {
> +                     ctrl->value = priv->gain;
> +             }
> +             break;
> +     case V4L2_CID_AUTO_WHITE_BALANCE:
> +             ctrl->value = priv->awb;
> +             break;
> +     case V4L2_CID_BLUE_BALANCE:
> +             if (priv->awb) {
> +                     ret = ov6650_reg_read(client, REG_BLUE, &reg);
> +                     ctrl->value = reg;
> +             } else {
> +                     ctrl->value = priv->blue;
> +             }
> +             break;
> +     case V4L2_CID_RED_BALANCE:
> +             if (priv->awb) {
> +                     ret = ov6650_reg_read(client, REG_RED, &reg);
> +                     ctrl->value = reg;
> +             } else {
> +                     ctrl->value = priv->red;
> +             }
> +             break;
> +     case V4L2_CID_SATURATION:
> +             ctrl->value = priv->saturation;
> +             break;
> +     case V4L2_CID_HUE_AUTO:
> +             ctrl->value = priv->hue_auto;
> +             break;
> +     case V4L2_CID_HUE:
> +             if (priv->hue_auto) {
> +                     ret = ov6650_reg_read(client, REG_HUE, &reg);
> +                     ctrl->value = reg & 0x1f;
> +             } else {
> +                     ctrl->value = priv->hue;
> +             }
> +             break;
> +     case V4L2_CID_BRIGHTNESS:
> +             ctrl->value = priv->brightness;
> +             break;
> +     case V4L2_CID_EXPOSURE_AUTO:
> +             ctrl->value = priv->aec;
> +             break;
> +     case V4L2_CID_EXPOSURE:
> +             if (priv->aec) {
> +                     ret = ov6650_reg_read(client, REG_AECH, &reg);
> +                     ctrl->value = reg;
> +             } else {
> +                     ctrl->value = priv->exposure;
> +             }
> +             break;
> +     case V4L2_CID_GAMMA:
> +             ctrl->value = priv->gamma;
> +             break;
> +     case V4L2_CID_VFLIP:
> +             ctrl->value = priv->vflip;
> +             break;
> +     case V4L2_CID_HFLIP:
> +             ctrl->value = priv->hflip;
> +             break;
> +     }
> +     return ret;
> +}
> +
> +/* Set status of additional camera capabilities */
> +static int ov6650_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct ov6650 *priv = to_ov6650(client);
> +     bool automatic;
> +     int ret = 0;
> +
> +     switch (ctrl->id) {
> +     case V4L2_CID_AUTOGAIN:
> +             if (ctrl->value) {
> +                     ret = ov6650_reg_write(client, REG_GAIN, DEF_GAIN);
> +                     if (ret)
> +                             break;
> +                     priv->gain = DEF_GAIN;
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AGC, 0);
> +             } else {
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AGC);
> +             }
> +             if (ret)
> +                     break;
> +             priv->agc = ctrl->value;
> +             break;
> +     case V4L2_CID_GAIN:
> +             ret = ov6650_reg_write(client, REG_GAIN, ctrl->value);
> +             if (ret)
> +                     break;
> +             priv->gain = ctrl->value;
> +             automatic = (priv->gain == DEF_GAIN);
> +             if (automatic)
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AGC, 0);
> +             else
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AGC);
> +             if (ret)
> +                     break;
> +             priv->agc = automatic;

I wouldn't touch autogain here. You have V4L2_CID_AUTOGAIN for that. 
Setting gain to a value, that happens to be equal default, doesn't have to 
turn autogain on, does it?

> +             break;
> +     case V4L2_CID_AUTO_WHITE_BALANCE:
> +             if (ctrl->value) {
> +                     ret = ov6650_reg_write(client, REG_BLUE, DEF_BLUE);
> +                     if (ret)
> +                             break;
> +                     priv->blue = DEF_BLUE;
> +                     ret = ov6650_reg_write(client, REG_RED, DEF_RED);
> +                     if (ret)
> +                             break;
> +                     priv->red = DEF_RED;
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AWB, 0);
> +             } else {
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AWB);
> +             }
> +             if (ret)
> +                     break;
> +             priv->awb = ctrl->value;
> +             break;
> +     case V4L2_CID_BLUE_BALANCE:
> +             ret = ov6650_reg_write(client, REG_BLUE, ctrl->value);
> +             if (ret)
> +                     break;
> +             priv->blue = ctrl->value;
> +             automatic = (priv->blue == DEF_BLUE &&
> +                             priv->red == DEF_RED);
> +             if (automatic)
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AWB, 0);
> +             else
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AWB);
> +             if (ret)
> +                     break;
> +             priv->awb = automatic;
> +             break;
> +     case V4L2_CID_RED_BALANCE:
> +             ret = ov6650_reg_write(client, REG_RED, ctrl->value);
> +             if (ret)
> +                     break;
> +             priv->red = ctrl->value;
> +             automatic = (priv->blue == DEF_BLUE &&
> +                             priv->red == DEF_RED);
> +             if (automatic)
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AWB, 0);
> +             else
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AWB);
> +             if (ret)
> +                     break;
> +             priv->awb = automatic;

Same here, I wouldn't touch AWB in the above two controls. You have 
V4L2_CID_AUTO_WHITE_BALANCE for that.

> +             break;
> +     case V4L2_CID_SATURATION:
> +             ret = ov6650_reg_rmw(client, REG_SAT, SET_SAT(ctrl->value),
> +                             SET_SAT(SAT_MASK));

With the proposed change it would look like

+               ret = ov6650_reg_rmw(client, REG_SAT, SET_SAT(ctrl->value),
+                               SAT_MASK);

which I personally find a bit more pleasant to the eyes;)

> +             if (ret)
> +                     break;
> +             priv->saturation = ctrl->value;
> +             break;
> +     case V4L2_CID_HUE_AUTO:
> +             if (ctrl->value) {
> +                     ret = ov6650_reg_rmw(client, REG_HUE,
> +                                     SET_HUE(DEF_HUE), SET_HUE(HUE_MASK));
> +                     if (ret)
> +                             break;
> +                     priv->hue = DEF_HUE;
> +             } else {
> +                     ret = ov6650_reg_rmw(client, REG_HUE, HUE_EN, 0);
> +             }
> +             if (ret)
> +                     break;
> +             priv->hue_auto = ctrl->value;

Hm, sorry, don't understand. If the user sets auto-hue to ON, you set the 
hue enable bit and hue value to default. If the user sets auto-hue to OFF, 
you just set the hue enable bit on and don't change the value. Does ov6650 
actually support auto-hue?

> +             break;
> +     case V4L2_CID_HUE:
> +             ret = ov6650_reg_rmw(client, REG_HUE, SET_HUE(ctrl->value),
> +                             SET_HUE(HUE_MASK));
> +             if (ret)
> +                     break;
> +             priv->hue = ctrl->value;
> +             priv->hue_auto = (priv->hue == DEF_HUE);

Here it seems like in order to adjust hue you always have to set the 
enable bit. Again, I wouldn't touch hue_auto here - default and auto are 
different things.

> +             break;
> +     case V4L2_CID_BRIGHTNESS:
> +             ret = ov6650_reg_write(client, REG_BRT, ctrl->value);
> +             if (ret)
> +                     break;
> +             priv->brightness = ctrl->value;
> +             break;
> +     case V4L2_CID_EXPOSURE_AUTO:
> +             switch (ctrl->value) {
> +             case V4L2_EXPOSURE_AUTO:
> +                     ret = ov6650_reg_write(client, REG_AECH, DEF_AECH);

Is this a requirement for auto-exposure, that you have to set the (analog 
manual) exposure to the default value?

> +                     if (ret)
> +                             break;
> +                     priv->exposure = DEF_AECH;
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AEC, 0);
> +                     break;
> +             default:
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AEC);
> +                     break;
> +             }
> +             if (ret)
> +                     break;
> +             priv->aec = ctrl->value;
> +             break;
> +     case V4L2_CID_EXPOSURE:
> +             ret = ov6650_reg_write(client, REG_AECH, ctrl->value);
> +             if (ret)
> +                     break;
> +             priv->exposure = ctrl->value;
> +             automatic = (priv->exposure == DEF_AECH);
> +             if (automatic)
> +                     ret = ov6650_reg_rmw(client, REG_COMB, COMB_AEC, 0);
> +             else
> +                     ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_AEC);
> +             if (ret)
> +                     break;
> +             priv->aec = automatic ? V4L2_EXPOSURE_AUTO :
> +                             V4L2_EXPOSURE_MANUAL;

Again - don't see why you need to touch the auto setting here.

> +             break;
> +     case V4L2_CID_GAMMA:
> +             ret = ov6650_reg_write(client, REG_GAM1, ctrl->value);
> +             if (ret)
> +                     break;
> +             priv->gamma = ctrl->value;
> +             break;
> +     case V4L2_CID_VFLIP:
> +             if (ctrl->value)
> +                     ret = ov6650_reg_rmw(client, REG_COMB,
> +                                                     COMB_FLIP_V, 0);
> +             else
> +                     ret = ov6650_reg_rmw(client, REG_COMB,
> +                                                     0, COMB_FLIP_V);
> +             if (ret)
> +                     break;
> +             priv->vflip = ctrl->value;
> +             break;
> +     case V4L2_CID_HFLIP:
> +             if (ctrl->value)
> +                     ret = ov6650_reg_rmw(client, REG_COMB,
> +                                                     COMB_FLIP_H, 0);
> +             else
> +                     ret = ov6650_reg_rmw(client, REG_COMB,
> +                                                     0, COMB_FLIP_H);
> +             if (ret)
> +                     break;
> +             priv->hflip = ctrl->value;
> +             break;
> +     }
> +
> +     return ret;
> +}
> +
> +/* Get chip identification */
> +static int ov6650_g_chip_ident(struct v4l2_subdev *sd,
> +                             struct v4l2_dbg_chip_ident *id)
> +{
> +     id->ident       = V4L2_IDENT_OV6650;
> +     id->revision    = 0;
> +
> +     return 0;
> +}
> +
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +static int ov6650_get_register(struct v4l2_subdev *sd,
> +                             struct v4l2_dbg_register *reg)
> +{
> +     struct i2c_client *client = sd->priv;
> +     int ret;
> +     u8 val;
> +
> +     if (reg->reg & ~0xff)
> +             return -EINVAL;
> +
> +     reg->size = 1;
> +
> +     ret = ov6650_reg_read(client, reg->reg, &val);
> +     if (ret)
> +             return ret;
> +
> +     reg->val = (__u64)val;
> +
> +     return 0;
> +}
> +
> +static int ov6650_set_register(struct v4l2_subdev *sd,
> +                             struct v4l2_dbg_register *reg)
> +{
> +     struct i2c_client *client = sd->priv;
> +
> +     if (reg->reg & ~0xff || reg->val & ~0xff)
> +             return -EINVAL;
> +
> +     return ov6650_reg_write(client, reg->reg, reg->val);
> +}
> +#endif
> +
> +/* select nearest higher resolution for capture */
> +static void ov6650_res_roundup(u32 *width, u32 *height)
> +{
> +     int i;
> +     enum { QCIF, CIF };
> +     int res_x[] = { 176, 352 };
> +     int res_y[] = { 144, 288 };
> +
> +     for (i = 0; i < ARRAY_SIZE(res_x); i++) {
> +             if (res_x[i] >= *width && res_y[i] >= *height) {
> +                     *width = res_x[i];
> +                     *height = res_y[i];
> +                     return;
> +             }
> +     }
> +
> +     *width = res_x[CIF];
> +     *height = res_y[CIF];
> +}

This can be replaced by a version of

http://www.spinics.net/lists/linux-media/msg21893.html

when it is fixed and accepted;) I'll try to send an updated version of 
that patch tomorrow.

> +
> +/* program default register values */
> +static int ov6650_prog_dflt(struct i2c_client *client)
> +{
> +     int i, ret;
> +
> +     dev_dbg(&client->dev, "reinitializing\n");
> +
> +     for (i = 0; i < ARRAY_SIZE(ov6650_regs_dflt); i++) {
> +             ret = ov6650_reg_write(client, ov6650_regs_dflt[i].reg,
> +                                             ov6650_regs_dflt[i].val);
> +             if (ret)
> +                     return ret;
> +     }

Hm, please, don't. I generally don't like such register - value array 
magic for a number of reasons, and in your case it's just one (!) register 
write operation - please, remove this array and just write the register 
explicitly. You also don't need DEF_COMA - writing an explicit "0" and 
adding a comment - "clear all flags, including reset" would be perfect!

> +
> +     return 0;
> +}
> +
> +/* set the format we will capture in */
> +static int ov6650_s_fmt(struct v4l2_subdev *sd,
> +                     struct v4l2_mbus_framefmt *mf)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct soc_camera_device *icd   = client->dev.platform_data;
> +     struct soc_camera_sense *sense = icd->sense;
> +     struct ov6650 *priv = to_ov6650(client);
> +     enum v4l2_colorspace cspace;
> +     enum v4l2_mbus_pixelcode code = mf->code;
> +     unsigned long pclk;
> +     u8 coma_set = 0, coma_mask = 0, coml_set = 0, coml_mask = 0, clkrc;
> +     int ret;
> +
> +     /* select color matrix configuration for given color encoding */
> +     switch (code) {
> +     case V4L2_MBUS_FMT_GREY8_1X8:
> +             dev_dbg(&client->dev, "pixel format GREY8_1X8\n");
> +             coma_set |= COMA_BW;
> +             coma_mask |= COMA_RGB | COMA_WORD_SWAP | COMA_BYTE_SWAP;
> +             coml_mask |= COML_ONE_CHANNEL;
> +             cspace = V4L2_COLORSPACE_JPEG;
> +             priv->pclk_max = 4000000;
> +             break;
> +     case V4L2_MBUS_FMT_YUYV8_2X8_LE:
> +             dev_dbg(&client->dev, "pixel format YUYV8_2X8_LE\n");
> +             coma_set |= COMA_WORD_SWAP;
> +             coma_mask |= COMA_RGB | COMA_BW | COMA_BYTE_SWAP;
> +             goto yuv;

Well, this doesn't look critical to me, i.e., eventually I would accept 
this, but, as you know, goto's in the kernel are (almost) only used for 
failure cases, besides, what makes this use even less pretty, this is a 
goto into a switch statement... I would set a "yuv = 1" variable instead 
of goto's, and use a "if (yuv) after the switch.

> +     case V4L2_MBUS_FMT_YVYU8_2X8_LE:
> +             dev_dbg(&client->dev, "pixel format YVYU8_2X8_LE (untested)\n");
> +             coma_mask |= COMA_RGB | COMA_BW | COMA_WORD_SWAP |
> +                             COMA_BYTE_SWAP;
> +             goto yuv;
> +     case V4L2_MBUS_FMT_YUYV8_2X8_BE:
> +             dev_dbg(&client->dev, "pixel format YUYV8_2X8_BE\n");
> +             if (mf->width == W_CIF) {
> +                     coma_set |= COMA_BYTE_SWAP | COMA_WORD_SWAP;
> +                     coma_mask |= COMA_RGB | COMA_BW;
> +             } else {
> +                     coma_set |= COMA_BYTE_SWAP;
> +                     coma_mask |= COMA_RGB | COMA_BW | COMA_WORD_SWAP;
> +             }
> +             goto yuv;
> +     case V4L2_MBUS_FMT_YVYU8_2X8_BE:
> +             dev_dbg(&client->dev, "pixel format YVYU8_2X8_BE (untested)\n");
> +             if (mf->width == W_CIF) {
> +                     coma_set |= COMA_BYTE_SWAP;
> +                     coma_mask |= COMA_RGB | COMA_BW | COMA_WORD_SWAP;
> +             } else {
> +                     coma_set |= COMA_BYTE_SWAP | COMA_WORD_SWAP;
> +                     coma_mask |= COMA_RGB | COMA_BW;
> +             }
> +yuv:
> +             coml_set |= COML_ONE_CHANNEL;
> +             cspace = V4L2_COLORSPACE_JPEG;
> +             priv->pclk_max = 8000000;
> +             break;
> +     case V4L2_MBUS_FMT_SBGGR8_1X8:
> +             dev_dbg(&client->dev, "pixel format SBGGR8_1X8 (untested)\n");
> +             coma_set |= COMA_RAW_RGB | COMA_RGB;
> +             coma_mask |= COMA_BW | COMA_BYTE_SWAP | COMA_WORD_SWAP;
> +             coml_mask |= COML_ONE_CHANNEL;
> +             cspace = V4L2_COLORSPACE_SRGB;
> +             priv->pclk_max = 4000000;
> +             break;
> +     default:
> +             dev_err(&client->dev, "Pixel format not handled : %x\n", code);
> +             return -EINVAL;
> +     }
> +
> +     /* select register configuration for given resolution */
> +     ov6650_res_roundup(&mf->width, &mf->height);
> +
> +     switch (mf->width) {
> +     case W_QCIF:
> +             dev_dbg(&client->dev, "resolution QCIF\n");
> +             priv->qcif = 1;
> +             coma_set |= COMA_QCIF;
> +             priv->pclk_max /= 2;
> +             break;
> +     case W_CIF:
> +             dev_dbg(&client->dev, "resolution CIF\n");
> +             priv->qcif = 0;
> +             coma_mask |= COMA_QCIF;
> +             break;
> +     default:
> +             dev_err(&client->dev, "unspported resolution!\n");
> +             return -EINVAL;
> +     }
> +
> +     if (priv->timeperframe.numerator && priv->timeperframe.denominator)
> +             pclk = priv->pclk_max * priv->timeperframe.denominator /
> +                             (FRAME_RATE_MAX * priv->timeperframe.numerator);
> +     else
> +             pclk = priv->pclk_max;
> +
> +     if (sense) {
> +             if (sense->master_clock == 8000000) {
> +                     dev_dbg(&client->dev, "8MHz input clock\n");
> +                     clkrc = CLKRC_6MHz;
> +             } else if (sense->master_clock == 12000000) {
> +                     dev_dbg(&client->dev, "12MHz input clock\n");
> +                     clkrc = CLKRC_12MHz;
> +             } else if (sense->master_clock == 16000000) {
> +                     dev_dbg(&client->dev, "16MHz input clock\n");
> +                     clkrc = CLKRC_16MHz;
> +             } else if (sense->master_clock == 24000000) {
> +                     dev_dbg(&client->dev, "24MHz input clock\n");
> +                     clkrc = CLKRC_24MHz;
> +             } else {
> +                     dev_err(&client->dev,
> +                             "unspported input clock, check platform data"
> +                             "\n");
> +                     return -EINVAL;
> +             }
> +             priv->pclk_limit = sense->pixel_clock_max;
> +             if (priv->pclk_limit &&
> +                             (priv->pclk_limit < pclk))

This can go on one line.

> +                     pclk = priv->pclk_limit;
> +     } else {
> +             priv->pclk_limit = 0;
> +             clkrc = 0xc0;
> +             dev_dbg(&client->dev, "using default 24MHz input clock\n");
> +     }
> +
> +     clkrc |= (priv->pclk_max - 1) / pclk;
> +     pclk = priv->pclk_max / GET_CLKRC_DIV(clkrc);

This would look better as

        clkrc_div = (priv->pclk_max - 1) / pclk;
        clkrc |= clkrc_div;
        pclk = priv->pclk_max / clkrc_div;

> +     dev_dbg(&client->dev, "pixel clock divider: %ld.%ld\n",
> +                     sense->master_clock / pclk,
> +                     10 * sense->master_clock % pclk / pclk);
> +
> +     ov6650_reset(client);
> +
> +     ret = ov6650_prog_dflt(client);
> +     if (ret)
> +             return ret;
> +
> +

Superfluous empty line;)

> +     ret = ov6650_reg_rmw(client, REG_COMA, coma_set, coma_mask);
> +     if (!ret)
> +             ret = ov6650_reg_write(client, REG_CLKRC, clkrc);
> +     if (!ret)
> +             ret = ov6650_reg_rmw(client, REG_COML, coml_set, coml_mask);
> +
> +     if (!ret) {
> +             mf->code        = code;
> +             mf->colorspace  = cspace;
> +     }
> +
> +     return ret;
> +}
> +
> +static int ov6650_try_fmt(struct v4l2_subdev *sd,
> +                       struct v4l2_mbus_framefmt *mf)
> +{
> +     ov6650_res_roundup(&mf->width, &mf->height);
> +
> +     mf->field = V4L2_FIELD_NONE;
> +
> +     switch (mf->code) {
> +     case V4L2_MBUS_FMT_Y10_1X10:
> +             mf->code = V4L2_MBUS_FMT_GREY8_1X8;
> +     case V4L2_MBUS_FMT_GREY8_1X8:
> +     case V4L2_MBUS_FMT_YVYU8_2X8_LE:
> +     case V4L2_MBUS_FMT_YUYV8_2X8_LE:
> +     case V4L2_MBUS_FMT_YVYU8_2X8_BE:
> +     case V4L2_MBUS_FMT_YUYV8_2X8_BE:
> +             mf->colorspace = V4L2_COLORSPACE_JPEG;
> +             break;
> +     default:
> +             mf->code = V4L2_MBUS_FMT_SBGGR8_1X8;
> +     case V4L2_MBUS_FMT_SBGGR8_1X8:
> +             mf->colorspace = V4L2_COLORSPACE_SRGB;
> +             break;
> +     }
> +
> +     return 0;
> +}
> +
> +static int ov6650_enum_fmt(struct v4l2_subdev *sd, unsigned int index,
> +                        enum v4l2_mbus_pixelcode *code)
> +{
> +     if ((unsigned int)index >= ARRAY_SIZE(ov6650_codes))
> +             return -EINVAL;
> +
> +     *code = ov6650_codes[index];
> +     return 0;
> +}
> +
> +static int ov6650_cropcap(struct v4l2_subdev *sd, struct v4l2_cropcap *a)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct ov6650 *priv = to_ov6650(client);
> +     int shift = !priv->qcif;
> +
> +     if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     /* Crop limits depend on selected frame format (CIF/QCIF) */
> +     a->bounds.left                  = DEF_HSTRT << shift;
> +     a->bounds.top                   = DEF_VSTRT << shift;
> +     a->bounds.width                 = W_QCIF << shift;
> +     a->bounds.height                = H_QCIF << shift;
> +     /* REVISIT: should defrect provide actual or default geometry? */

default

> +     a->defrect                      = a->bounds;
> +     a->pixelaspect.numerator        = 1;
> +     a->pixelaspect.denominator      = 1;
> +
> +     return 0;
> +}
> +
> +static int ov6650_g_crop(struct v4l2_subdev *sd, struct v4l2_crop *a)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct ov6650 *priv = to_ov6650(client);
> +     struct v4l2_rect *rect = &a->c;
> +     int shift = !priv->qcif;
> +     u8 hstrt, vstrt, hstop, vstop;
> +     int ret;
> +
> +     if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     ret = ov6650_reg_read(client, REG_HSTRT, &hstrt);
> +     if (!ret)
> +             ret = ov6650_reg_read(client, REG_HSTOP, &hstop);
> +     if (!ret)
> +             ret = ov6650_reg_read(client, REG_VSTRT, &vstrt);
> +     if (!ret)
> +             ret = ov6650_reg_read(client, REG_VSTOP, &vstop);
> +
> +     if (!ret) {
> +             rect->left      = hstrt << shift;
> +             rect->top       = vstrt << shift;
> +             rect->width     = (hstop - hstrt) << shift;
> +             rect->height    = (vstop - vstrt) << shift;
> +     }
> +
> +     return ret;
> +}
> +
> +static int ov6650_s_crop(struct v4l2_subdev *sd, struct v4l2_crop *a)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct ov6650 *priv = to_ov6650(client);
> +     struct v4l2_rect *rect = &a->c;
> +     int shift = !priv->qcif;
> +     u8 hstrt, vstrt, hstop, vstop;
> +     int ret;
> +
> +     if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     hstrt = rect->left >> shift;
> +     vstrt = rect->top >> shift;
> +     hstop = hstrt + (rect->width >> shift);
> +     vstop = vstrt + (rect->height >> shift);
> +
> +     if ((hstop > DEF_HSTOP) || (vstop > DEF_VSTOP)) {
> +             dev_err(&client->dev, "Invalid window geometry!\n");
> +             return -EINVAL;
> +     }
> +
> +     ret = ov6650_reg_write(client, REG_HSTRT, hstrt);
> +     if (!ret)
> +             ret = ov6650_reg_write(client, REG_HSTOP, hstop);
> +     if (!ret)
> +             ret = ov6650_reg_write(client, REG_VSTRT, vstrt);
> +     if (!ret)
> +             ret = ov6650_reg_write(client, REG_VSTOP, vstop);

Are cropping and scaling on this camera absolutely independent? I.e., you 
can set any output format (CIF or QCIF) and it will just scale whatever 
rectangle has been configured? And the other way round - you set arbitrary 
cropping and output format stays the same?

> +
> +     return ret;
> +}
> +
> +static int ov6650_g_parm(struct v4l2_subdev *sd, struct v4l2_streamparm 
> *parms)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct v4l2_captureparm *cp = &parms->parm.capture;
> +     u8 clkrc;
> +     int ret;
> +
> +     if (parms->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     ret = ov6650_reg_read(client, REG_CLKRC, &clkrc);
> +     if (ret < 0)
> +             return ret;
> +
> +     memset(cp, 0, sizeof(struct v4l2_captureparm));
> +     cp->capability = V4L2_CAP_TIMEPERFRAME;
> +     cp->timeperframe.numerator = GET_CLKRC_DIV(clkrc);
> +     cp->timeperframe.denominator = FRAME_RATE_MAX;
> +
> +     dev_dbg(&client->dev, "Frame interval: %u/%u\n",
> +             cp->timeperframe.numerator, cp->timeperframe.denominator);
> +
> +     return 0;
> +}
> +
> +static int ov6650_s_parm(struct v4l2_subdev *sd, struct v4l2_streamparm 
> *parms)
> +{
> +     struct i2c_client *client = sd->priv;
> +     struct ov6650 *priv = to_ov6650(client);
> +     struct v4l2_captureparm *cp = &parms->parm.capture;
> +     struct v4l2_fract *tpf = &cp->timeperframe;
> +     int div, ret;
> +
> +     if (parms->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +             return -EINVAL;
> +
> +     if (cp->extendedmode != 0)
> +             return -EINVAL;
> +
> +     if (tpf->numerator == 0 || tpf->denominator == 0)
> +             div = 1;  /* Reset to full rate */
> +     else
> +             div = (tpf->numerator * FRAME_RATE_MAX) / tpf->denominator;
> +
> +     if (div == 0)
> +             div = 1;
> +     else if (div > CLKRC_DIV_MASK + 1)
> +             div = CLKRC_DIV_MASK + 1;
> +
> +     if (priv->pclk_max && priv->pclk_limit) {
> +             ret = (priv->pclk_max - 1) / priv->pclk_limit;
> +             if (div < ret)
> +                     div = ret;
> +     }
> +
> +     ret = ov6650_reg_rmw(client, REG_CLKRC, div - 1, CLKRC_DIV_MASK);
> +     if (!ret) {
> +             priv->timeperframe.numerator = tpf->numerator = FRAME_RATE_MAX;
> +             priv->timeperframe.denominator = tpf->denominator = div;
> +     }
> +
> +     return ret;
> +}
> +
> +static int ov6650_video_probe(struct soc_camera_device *icd,
> +                             struct i2c_client *client)
> +{
> +     u8              pidh, pidl, midh, midl;
> +     int             ret = 0;
> +
> +     /*
> +      * check and show product ID and manufacturer ID
> +      */
> +     ret = ov6650_reg_read(client, REG_PIDH, &pidh);
> +     if (!ret)
> +             ret = ov6650_reg_read(client, REG_PIDL, &pidl);
> +     if (!ret)
> +             ret = ov6650_reg_read(client, REG_MIDH, &midh);
> +     if (!ret)
> +             ret = ov6650_reg_read(client, REG_MIDL, &midl);
> +
> +     if (ret)
> +             goto err;
> +
> +     if ((pidh != OV6650_PIDH) || (pidl != OV6650_PIDL)) {
> +             dev_err(&client->dev, "Product ID error %x:%x\n", pidh, pidl);
> +             ret = -ENODEV;
> +             goto err;
> +     }
> +
> +     dev_info(&client->dev, "ov6650 Product ID %0x:%0x Manufacturer ID %x:%x"
> +                     "\n", pidh, pidl, midh, midl);
> +
> +err:
> +     return ret;
> +}
> +
> +static struct soc_camera_ops ov6650_ops = {
> +     .set_bus_param          = ov6650_set_bus_param,
> +     .query_bus_param        = ov6650_query_bus_param,
> +     .controls               = ov6650_controls,
> +     .num_controls           = ARRAY_SIZE(ov6650_controls),
> +};
> +
> +static struct v4l2_subdev_core_ops ov6650_core_ops = {
> +     .g_ctrl                 = ov6650_g_ctrl,
> +     .s_ctrl                 = ov6650_s_ctrl,
> +     .g_chip_ident           = ov6650_g_chip_ident,
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +     .g_register             = ov6650_get_register,
> +     .s_register             = ov6650_set_register,
> +#endif
> +

Superfluous empty line

> +};
> +
> +static struct v4l2_subdev_video_ops ov6650_video_ops = {
> +     .s_stream       = ov6650_s_stream,
> +     .s_mbus_fmt     = ov6650_s_fmt,
> +     .try_mbus_fmt   = ov6650_try_fmt,

Please, implement.g_mbus_fmt.

> +     .enum_mbus_fmt  = ov6650_enum_fmt,
> +     .cropcap        = ov6650_cropcap,
> +     .g_crop         = ov6650_g_crop,
> +     .s_crop         = ov6650_s_crop,
> +     .g_parm         = ov6650_g_parm,
> +     .s_parm         = ov6650_s_parm,
> +

Superfluous empty line

> +};
> +
> +static struct v4l2_subdev_ops ov6650_subdev_ops = {
> +     .core   = &ov6650_core_ops,
> +     .video  = &ov6650_video_ops,
> +};
> +
> +/*
> + * i2c_driver function
> + */
> +static int ov6650_probe(struct i2c_client *client,
> +                     const struct i2c_device_id *did)
> +{
> +     struct ov6650 *priv;
> +     struct soc_camera_device *icd   = client->dev.platform_data;

Nothing to align here, a space before "=" would suffice;)

> +     struct soc_camera_link *icl;
> +     int ret;
> +
> +     if (!icd) {
> +             dev_err(&client->dev, "Missing soc-camera data!\n");
> +             return -EINVAL;
> +     }
> +
> +     icl = to_soc_camera_link(icd);
> +     if (!icl) {
> +             dev_err(&client->dev, "Missing platform_data for driver\n");
> +             return -EINVAL;
> +     }
> +
> +     priv = kzalloc(sizeof(struct ov6650), GFP_KERNEL);
> +     if (!priv) {
> +             dev_err(&client->dev,
> +                     "Failed to allocate memory for private data!\n");
> +             return -ENOMEM;
> +     }
> +
> +     v4l2_i2c_subdev_init(&priv->subdev, client, &ov6650_subdev_ops);
> +
> +     icd->ops        = &ov6650_ops;

A matter of taste, eventually, but I'd use a space.

> +
> +     ret = ov6650_video_probe(icd, client);
> +
> +     if (ret) {
> +             icd->ops = NULL;
> +             i2c_set_clientdata(client, NULL);
> +             kfree(priv);
> +     }
> +
> +     return ret;
> +}
> +
> +static int ov6650_remove(struct i2c_client *client)
> +{
> +     struct ov6650 *priv = to_ov6650(client);
> +
> +     i2c_set_clientdata(client, NULL);
> +     kfree(priv);
> +     return 0;
> +}
> +
> +static const struct i2c_device_id ov6650_id[] = {
> +     { "ov6650", 0 },
> +     { }
> +};
> +MODULE_DEVICE_TABLE(i2c, ov6650_id);
> +
> +static struct i2c_driver ov6650_i2c_driver = {
> +     .driver = {
> +             .name = "ov6650",
> +     },
> +     .probe    = ov6650_probe,
> +     .remove   = ov6650_remove,
> +     .id_table = ov6650_id,
> +};
> +
> +static int __init ov6650_module_init(void)
> +{
> +     return i2c_add_driver(&ov6650_i2c_driver);
> +}
> +
> +static void __exit ov6650_module_exit(void)
> +{
> +     i2c_del_driver(&ov6650_i2c_driver);
> +}
> +
> +module_init(ov6650_module_init);
> +module_exit(ov6650_module_exit);
> +
> +MODULE_DESCRIPTION("SoC Camera driver for OmniVision OV6650");
> +MODULE_AUTHOR("Janusz Krzysztofik <jkrzy...@tis.icnet.pl>");
> +MODULE_LICENSE("GPL v2");
> --- linux-2.6.35-rc3.orig/include/media/v4l2-chip-ident.h     2010-06-26 
> 15:56:15.000000000 +0200
> +++ linux-2.6.35-rc3/include/media/v4l2-chip-ident.h  2010-06-26 
> 17:28:09.000000000 +0200
> @@ -70,6 +70,7 @@ enum {
>       V4L2_IDENT_OV9655 = 255,
>       V4L2_IDENT_SOI968 = 256,
>       V4L2_IDENT_OV9640 = 257,
> +     V4L2_IDENT_OV6650 = 258,
>  
>       /* module saa7146: reserved range 300-309 */
>       V4L2_IDENT_SAA7146 = 300,
> 

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