V4L/DVB (4798): OmniVision OV7670 driver

This patch adds a V4L2 driver for the OmniVision OV7670 camera.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 1002 insertions, 0 deletions

diff --git a/drivers/media/video/ov7670.c b/drivers/media/video/ov7670.c
new file mode 100644
index 000000000000..382aa83b73c5
--- /dev/null
+++ b/drivers/media/video/ov7670.c
@@ -0,0 +1,1002 @@
+/*
+ * A V4L2 driver for OmniVision OV7670 cameras.
+ *
+ * Copyright 2006 One Laptop Per Child Association, Inc.  Written
+ * by Jonathan Corbet with substantial inspiration from Mark
+ * McClelland's ovcamchip code.
+ *
+ * This file may be distributed under the terms of the GNU General
+ * Public License, version 2.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/videodev.h>
+#include <media/v4l2-common.h>
+#include <linux/i2c.h>
+
+
+MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net.");
+MODULE_DESCRIPTION("A low-level driver for OmniVision ov7670 sensors");
+MODULE_LICENSE("GPL");
+
+/*
+ * Basic window sizes.  These probably belong somewhere more globally
+ * useful.
+ */
+#define VGA_WIDTH       640
+#define VGA_HEIGHT      480
+#define QVGA_WIDTH      320
+#define QVGA_HEIGHT     240
+#define CIF_WIDTH       352
+#define CIF_HEIGHT      288
+#define QCIF_WIDTH      176
+#define QCIF_HEIGHT     144
+
+/*
+ * The 7670 sits on i2c with ID 0x42
+ */
+#define OV7670_I2C_ADDR 0x42
+
+/* Registers */
+#define REG_GAIN        0x00    /* Gain lower 8 bits (rest in vref) */
+#define REG_BLUE        0x01    /* blue gain */
+#define REG_RED         0x02    /* red gain */
+#define REG_VREF        0x03    /* Pieces of GAIN, VSTART, VSTOP */
+#define REG_COM1        0x04    /* Control 1 */
+#define  COM1_CCIR656     0x40  /* CCIR656 enable */
+#define REG_BAVE        0x05    /* U/B Average level */
+#define REG_GbAVE       0x06    /* Y/Gb Average level */
+#define REG_AECHH       0x07    /* AEC MS 5 bits */
+#define REG_RAVE        0x08    /* V/R Average level */
+#define REG_COM2        0x09    /* Control 2 */
+#define  COM2_SSLEEP      0x10  /* Soft sleep mode */
+#define REG_PID         0x0a    /* Product ID MSB */
+#define REG_VER         0x0b    /* Product ID LSB */
+#define REG_COM3        0x0c    /* Control 3 */
+#define  COM3_SWAP        0x40    /* Byte swap */
+#define  COM3_SCALEEN     0x08    /* Enable scaling */
+#define  COM3_DCWEN       0x04    /* Enable downsamp/crop/window */
+#define REG_COM4        0x0d    /* Control 4 */
+#define REG_COM5        0x0e    /* All "reserved" */
+#define REG_COM6        0x0f    /* Control 6 */
+#define REG_AECH        0x10    /* More bits of AEC value */
+#define REG_CLKRC       0x11    /* Clocl control */
+#define   CLK_EXT         0x40    /* Use external clock directly */
+#define   CLK_SCALE       0x3f    /* Mask for internal clock scale */
+#define REG_COM7        0x12    /* Control 7 */
+#define   COM7_RESET      0x80    /* Register reset */
+#define   COM7_FMT_MASK   0x38
+#define   COM7_FMT_VGA    0x00
+#define   COM7_FMT_CIF    0x20    /* CIF format */
+#define   COM7_FMT_QVGA   0x10    /* QVGA format */
+#define   COM7_FMT_QCIF   0x08    /* QCIF format */
+#define   COM7_RGB        0x04    /* bits 0 and 2 - RGB format */
+#define   COM7_YUV        0x00    /* YUV */
+#define   COM7_BAYER      0x01    /* Bayer format */
+#define   COM7_PBAYER     0x05    /* "Processed bayer" */
+#define REG_COM8        0x13    /* Control 8 */
+#define   COM8_FASTAEC    0x80    /* Enable fast AGC/AEC */
+#define   COM8_AECSTEP    0x40    /* Unlimited AEC step size */
+#define   COM8_BFILT      0x20    /* Band filter enable */
+#define   COM8_AGC        0x04    /* Auto gain enable */
+#define   COM8_AWB        0x02    /* White balance enable */
+#define   COM8_AEC        0x01    /* Auto exposure enable */
+#define REG_COM9        0x14    /* Control 9  - gain ceiling */
+#define REG_COM10       0x15    /* Control 10 */
+#define   COM10_HSYNC     0x40    /* HSYNC instead of HREF */
+#define   COM10_PCLK_HB   0x20    /* Suppress PCLK on horiz blank */
+#define   COM10_HREF_REV  0x08    /* Reverse HREF */
+#define   COM10_VS_LEAD   0x04    /* VSYNC on clock leading edge */
+#define   COM10_VS_NEG    0x02    /* VSYNC negative */
+#define   COM10_HS_NEG    0x01    /* HSYNC negative */
+#define REG_HSTART      0x17    /* Horiz start high bits */
+#define REG_HSTOP       0x18    /* Horiz stop high bits */
+#define REG_VSTART      0x19    /* Vert start high bits */
+#define REG_VSTOP       0x1a    /* Vert stop high bits */
+#define REG_PSHFT       0x1b    /* Pixel delay after HREF */
+#define REG_MIDH        0x1c    /* Manuf. ID high */
+#define REG_MIDL        0x1d    /* Manuf. ID low */
+#define REG_MVFP        0x1e    /* Mirror / vflip */
+#define   MVFP_MIRROR     0x20    /* Mirror image */
+#define   MVFP_FLIP       0x10    /* Vertical flip */
+
+#define REG_AEW         0x24    /* AGC upper limit */
+#define REG_AEB         0x25    /* AGC lower limit */
+#define REG_VPT         0x26    /* AGC/AEC fast mode op region */
+#define REG_HSYST       0x30    /* HSYNC rising edge delay */
+#define REG_HSYEN       0x31    /* HSYNC falling edge delay */
+#define REG_HREF        0x32    /* HREF pieces */
+#define REG_TSLB        0x3a    /* lots of stuff */
+#define   TSLB_YLAST      0x04    /* UYVY or VYUY - see com13 */
+#define REG_COM11       0x3b    /* Control 11 */
+#define   COM11_NIGHT     0x80    /* NIght mode enable */
+#define   COM11_NMFR      0x60    /* Two bit NM frame rate */
+#define   COM11_HZAUTO    0x10    /* Auto detect 50/60 Hz */
+#define   COM11_50HZ      0x08    /* Manual 50Hz select */
+#define   COM11_EXP       0x02
+#define REG_COM12       0x3c    /* Control 12 */
+#define   COM12_HREF      0x80    /* HREF always */
+#define REG_COM13       0x3d    /* Control 13 */
+#define   COM13_GAMMA     0x80    /* Gamma enable */
+#define   COM13_UVSAT     0x40    /* UV saturation auto adjustment */
+#define   COM13_UVSWAP    0x01    /* V before U - w/TSLB */
+#define REG_COM14       0x3e    /* Control 14 */
+#define   COM14_DCWEN     0x10    /* DCW/PCLK-scale enable */
+#define REG_EDGE        0x3f    /* Edge enhancement factor */
+#define REG_COM15       0x40    /* Control 15 */
+#define   COM15_R10F0     0x00    /* Data range 10 to F0 */
+#define   COM15_R01FE     0x80    /*            01 to FE */
+#define   COM15_R00FF     0xc0    /*            00 to FF */
+#define   COM15_RGB565    0x10    /* RGB565 output */
+#define   COM15_RGB555    0x30    /* RGB555 output */
+#define REG_COM16       0x41    /* Control 16 */
+#define   COM16_AWBGAIN   0x08    /* AWB gain enable */
+#define REG_COM17       0x42    /* Control 17 */
+#define   COM17_AECWIN    0xc0    /* AEC window - must match COM4 */
+#define   COM17_CBAR      0x08    /* DSP Color bar */
+
+#define REG_BRIGHT      0x55    /* Brightness */
+#define REG_CONTRAS     0x56    /* Contrast control */
+
+#define REG_GFIX        0x69    /* Fix gain control */
+
+#define REG_RGB444      0x8c    /* RGB 444 control */
+#define   R444_ENABLE     0x02    /* Turn on RGB444, overrides 5x5 */
+#define   R444_RGBX       0x01    /* Empty nibble at end */
+
+#define REG_HAECC1      0x9f    /* Hist AEC/AGC control 1 */
+#define REG_HAECC2      0xa0    /* Hist AEC/AGC control 2 */
+
+#define REG_BD50MAX     0xa5    /* 50hz banding step limit */
+#define REG_HAECC3      0xa6    /* Hist AEC/AGC control 3 */
+#define REG_HAECC4      0xa7    /* Hist AEC/AGC control 4 */
+#define REG_HAECC5      0xa8    /* Hist AEC/AGC control 5 */
+#define REG_HAECC6      0xa9    /* Hist AEC/AGC control 6 */
+#define REG_HAECC7      0xaa    /* Hist AEC/AGC control 7 */
+#define REG_BD60MAX     0xab    /* 60hz banding step limit */
+
+
+/*
+ * The default register settings, as obtained from OmniVision.  There
+ * is really no making sense of most of these - lots of "reserved" values
+ * and such.
+ *
+ * These settings give VGA YUYV.
+ */
+
+struct regval_list {
+        unsigned char reg_num;
+        unsigned char value;
+};
+
+static struct regval_list ov7670_default_regs[] = {
+        { REG_COM7, COM7_RESET },
+/*
+ * Clock scale: 3 = 15fps
+ *              2 = 20fps
+ *              1 = 30fps
+ */
+        { REG_CLKRC, 0x1 },     /* OV: clock scale (15 fps) */
+        { REG_TSLB,  0x04 },    /* OV */
+        { REG_COM7, 0 },        /* VGA */
+        /*
+         * Set the hardware window.  These values from OV don't entirely
+         * make sense - hstop is less than hstart.  But they work...
+         */
+        { REG_HSTART, 0x13 },   { REG_HSTOP, 0x01 },
+        { REG_HREF, 0xb6 },     { REG_VSTART, 0x02 },
+        { REG_VSTOP, 0x7a },    { REG_VREF, 0x0a },
+
+        { REG_COM3, 0 },        { REG_COM14, 0 },
+        /* Mystery scaling numbers */
+        { 0x70, 0x3a },         { 0x71, 0x35 },
+        { 0x72, 0x11 },         { 0x73, 0xf0 },
+        { 0xa2, 0x02 },         { REG_COM10, 0x0 },
+
+        /* Gamma curve values */
+        { 0x7a, 0x20 },         { 0x7b, 0x10 },
+        { 0x7c, 0x1e },         { 0x7d, 0x35 },
+        { 0x7e, 0x5a },         { 0x7f, 0x69 },
+        { 0x80, 0x76 },         { 0x81, 0x80 },
+        { 0x82, 0x88 },         { 0x83, 0x8f },
+        { 0x84, 0x96 },         { 0x85, 0xa3 },
+        { 0x86, 0xaf },         { 0x87, 0xc4 },
+        { 0x88, 0xd7 },         { 0x89, 0xe8 },
+
+        /* AGC and AEC parameters.  Note we start by disabling those features,
+           then turn them only after tweaking the values. */
+        { REG_COM8, COM8_FASTAEC | COM8_AECSTEP | COM8_BFILT },
+        { REG_GAIN, 0 },        { REG_AECH, 0 },
+        { REG_COM4, 0x40 }, /* magic reserved bit */
+        { REG_COM9, 0x18 }, /* 4x gain + magic rsvd bit */
+        { REG_BD50MAX, 0x05 },  { REG_BD60MAX, 0x07 },
+        { REG_AEW, 0x95 },      { REG_AEB, 0x33 },
+        { REG_VPT, 0xe3 },      { REG_HAECC1, 0x78 },
+        { REG_HAECC2, 0x68 },   { 0xa1, 0x03 }, /* magic */
+        { REG_HAECC3, 0xd8 },   { REG_HAECC4, 0xd8 },
+        { REG_HAECC5, 0xf0 },   { REG_HAECC6, 0x90 },
+        { REG_HAECC7, 0x94 },
+        { REG_COM8, COM8_FASTAEC|COM8_AECSTEP|COM8_BFILT|COM8_AGC|COM8_AEC },
+
+        /* Almost all of these are magic "reserved" values.  */
+        { REG_COM5, 0x61 },     { REG_COM6, 0x4b },
+        { 0x16, 0x02 },         { REG_MVFP, 0x07|MVFP_MIRROR },
+        { 0x21, 0x02 },         { 0x22, 0x91 },
+        { 0x29, 0x07 },         { 0x33, 0x0b },
+        { 0x35, 0x0b },         { 0x37, 0x1d },
+        { 0x38, 0x71 },         { 0x39, 0x2a },
+        { REG_COM12, 0x78 },    { 0x4d, 0x40 },
+        { 0x4e, 0x20 },         { REG_GFIX, 0 },
+        { 0x6b, 0x4a },         { 0x74, 0x10 },
+        { 0x8d, 0x4f },         { 0x8e, 0 },
+        { 0x8f, 0 },            { 0x90, 0 },
+        { 0x91, 0 },            { 0x96, 0 },
+        { 0x9a, 0 },            { 0xb0, 0x84 },
+        { 0xb1, 0x0c },         { 0xb2, 0x0e },
+        { 0xb3, 0x82 },         { 0xb8, 0x0a },
+
+        /* More reserved magic, some of which tweaks white balance */
+        { 0x43, 0x0a },         { 0x44, 0xf0 },
+        { 0x45, 0x34 },         { 0x46, 0x58 },
+        { 0x47, 0x28 },         { 0x48, 0x3a },
+        { 0x59, 0x88 },         { 0x5a, 0x88 },
+        { 0x5b, 0x44 },         { 0x5c, 0x67 },
+        { 0x5d, 0x49 },         { 0x5e, 0x0e },
+        { 0x6c, 0x0a },         { 0x6d, 0x55 },
+        { 0x6e, 0x11 },         { 0x6f, 0x9f }, /* "9e for advance AWB" */
+        { 0x6a, 0x40 },         { REG_BLUE, 0x40 },
+        { REG_RED, 0x60 },
+        { REG_COM8, COM8_FASTAEC|COM8_AECSTEP|COM8_BFILT|COM8_AGC|COM8_AEC|COM8_AWB },
+
+        /* Matrix coefficients */
+        { 0x4f, 0x80 },         { 0x50, 0x80 },
+        { 0x51, 0 },            { 0x52, 0x22 },
+        { 0x53, 0x5e },         { 0x54, 0x80 },
+        { 0x58, 0x9e },
+
+        { REG_COM16, COM16_AWBGAIN },   { REG_EDGE, 0 },
+        { 0x75, 0x05 },         { 0x76, 0xe1 },
+        { 0x4c, 0 },            { 0x77, 0x01 },
+        { REG_COM13, 0xc3 },    { 0x4b, 0x09 },
+        { 0xc9, 0x60 },         { REG_COM16, 0x38 },
+        { 0x56, 0x40 },
+
+        { 0x34, 0x11 },         { REG_COM11, COM11_EXP },
+        { 0xa4, 0x88 },         { 0x96, 0 },
+        { 0x97, 0x30 },         { 0x98, 0x20 },
+        { 0x99, 0x30 },         { 0x9a, 0x84 },
+        { 0x9b, 0x29 },         { 0x9c, 0x03 },
+        { 0x9d, 0x4c },         { 0x9e, 0x3f },
+        { 0x78, 0x04 },
+
+        /* Extra-weird stuff.  Some sort of multiplexor register */
+        { 0x79, 0x01 },         { 0xc8, 0xf0 },
+        { 0x79, 0x0f },         { 0xc8, 0x00 },
+        { 0x79, 0x10 },         { 0xc8, 0x7e },
+        { 0x79, 0x0a },         { 0xc8, 0x80 },
+        { 0x79, 0x0b },         { 0xc8, 0x01 },
+        { 0x79, 0x0c },         { 0xc8, 0x0f },
+        { 0x79, 0x0d },         { 0xc8, 0x20 },
+        { 0x79, 0x09 },         { 0xc8, 0x80 },
+        { 0x79, 0x02 },         { 0xc8, 0xc0 },
+        { 0x79, 0x03 },         { 0xc8, 0x40 },
+        { 0x79, 0x05 },         { 0xc8, 0x30 },
+        { 0x79, 0x26 },
+
+        /* Not sure if these should be here */
+        { 0xf1, 0x10 },         { 0x0f, 0x1d },
+        { 0x0f, 0x1f },
+
+        { 0xff, 0xff }, /* END MARKER */
+};
+
+
+/*
+ * Here we'll try to encapsulate the changes for just the output
+ * video format.
+ *
+ * RGB656 and YUV422 come from OV; RGB444 is homebrewed.
+ *
+ * IMPORTANT RULE: the first entry must be for COM7, see ov7670_s_fmt for why.
+ */
+
+
+static struct regval_list ov7670_fmt_yuv422[] = {
+        { REG_COM7, 0x0 },  /* Selects YUV mode */
+        { REG_RGB444, 0 },      /* No RGB444 please */
+        { REG_COM1, 0 },
+        { REG_COM15, COM15_R00FF },
+        { REG_COM9, 0x18 }, /* 4x gain ceiling; 0x8 is reserved bit */
+        { 0x4f, 0x80 },         /* "matrix coefficient 1" */
+        { 0x50, 0x80 },         /* "matrix coefficient 2" */
+        { 0x52, 0x22 },         /* "matrix coefficient 4" */
+        { 0x53, 0x5e },         /* "matrix coefficient 5" */
+        { 0x54, 0x80 },         /* "matrix coefficient 6" */
+        { REG_COM13, COM13_GAMMA|COM13_UVSAT },
+        { 0xff, 0xff },
+};
+
+static struct regval_list ov7670_fmt_rgb565[] = {
+        { REG_COM7, COM7_RGB }, /* Selects RGB mode */
+        { REG_RGB444, 0 },      /* No RGB444 please */
+        { REG_COM1, 0x0 },
+        { REG_COM15, COM15_RGB565 },
+        { REG_COM9, 0x38 },     /* 16x gain ceiling; 0x8 is reserved bit */
+        { 0x4f, 0xb3 },         /* "matrix coefficient 1" */
+        { 0x50, 0xb3 },         /* "matrix coefficient 2" */
+        { 0x52, 0x3d },         /* "matrix coefficient 4" */
+        { 0x53, 0xa7 },         /* "matrix coefficient 5" */
+        { 0x54, 0xe4 },         /* "matrix coefficient 6" */
+        { REG_COM13, COM13_GAMMA|COM13_UVSAT },
+        { 0xff, 0xff },
+};
+
+static struct regval_list ov7670_fmt_rgb444[] = {
+        { REG_COM7, COM7_RGB }, /* Selects RGB mode */
+        { REG_RGB444, R444_ENABLE },    /* Enable xxxxrrrr ggggbbbb */
+        { REG_COM1, 0x40 },     /* Magic reserved bit */
+        { REG_COM15, COM15_R01FE|COM15_RGB565 }, /* Data range needed? */
+        { REG_COM9, 0x38 },     /* 16x gain ceiling; 0x8 is reserved bit */
+        { 0x4f, 0xb3 },         /* "matrix coefficient 1" */
+        { 0x50, 0xb3 },         /* "matrix coefficient 2" */
+        { 0x52, 0x3d },         /* "matrix coefficient 4" */
+        { 0x53, 0xa7 },         /* "matrix coefficient 5" */
+        { 0x54, 0xe4 },         /* "matrix coefficient 6" */
+        { REG_COM13, COM13_GAMMA|COM13_UVSAT|0x2 },  /* Magic rsvd bit */
+        { 0xff, 0xff },
+};
+
+
+
+
+/*
+ * Low-level register I/O.
+ */
+
+static int ov7670_read(struct i2c_client *c, unsigned char reg,
+                unsigned char *value)
+{
+        int ret;
+
+        ret = i2c_smbus_read_byte_data(c, reg);
+        if (ret > 0)
+                *value = (unsigned char) ret;
+        return ret;
+}
+
+
+static int ov7670_write(struct i2c_client *c, unsigned char reg,
+                unsigned char value)
+{
+        return i2c_smbus_write_byte_data(c, reg, value);
+}
+
+
+/*
+ * Write a list of register settings; ff/ff stops the process.
+ */
+static int ov7670_write_array(struct i2c_client *c, struct regval_list *vals)
+{
+        while (vals->reg_num != 0xff || vals->value != 0xff) {
+                int ret = ov7670_write(c, vals->reg_num, vals->value);
+                if (ret < 0)
+                        return ret;
+                vals++;
+        }
+        return 0;
+}
+
+
+/*
+ * Stuff that knows about the sensor.
+ */
+static void ov7670_reset(struct i2c_client *client)
+{
+        ov7670_write(client, REG_COM7, COM7_RESET);
+        msleep(1);
+}
+
+
+static int ov7670_init(struct i2c_client *client)
+{
+        return ov7670_write_array(client, ov7670_default_regs);
+}
+
+
+
+static int ov7670_detect(struct i2c_client *client)
+{
+        unsigned char v;
+        int ret;
+
+        ret = ov7670_init(client);
+        if (ret < 0)
+                return ret;
+        ret = ov7670_read(client, REG_MIDH, &v);
+        if (ret < 0)
+                return ret;
+        if (v != 0x7f) /* OV manuf. id. */
+                return -ENODEV;
+        ret = ov7670_read(client, REG_MIDL, &v);
+        if (ret < 0)
+                return ret;
+        if (v != 0xa2)
+                return -ENODEV;
+        /*
+         * OK, we know we have an OmniVision chip...but which one?
+         */
+        ret = ov7670_read(client, REG_PID, &v);
+        if (ret < 0)
+                return ret;
+        if (v != 0x76)  /* PID + VER = 0x76 / 0x73 */
+                return -ENODEV;
+        ret = ov7670_read(client, REG_VER, &v);
+        if (ret < 0)
+                return ret;
+        if (v != 0x73)  /* PID + VER = 0x76 / 0x73 */
+                return -ENODEV;
+        return 0;
+}
+
+
+
+
+
+static struct ov7670_format_struct {
+        __u8 *desc;
+        __u32 pixelformat;
+        struct regval_list *regs;
+} ov7670_formats[] = {
+        {
+                .desc           = "YUYV 4:2:2",
+                .pixelformat    = V4L2_PIX_FMT_YUYV,
+                .regs           = ov7670_fmt_yuv422,
+        },
+        {
+                .desc           = "RGB 444",
+                .pixelformat    = V4L2_PIX_FMT_RGB444,
+                .regs           = ov7670_fmt_rgb444,
+        },
+        {
+                .desc           = "RGB 565",
+                .pixelformat    = V4L2_PIX_FMT_RGB565,
+                .regs           = ov7670_fmt_rgb565,
+        },
+        /*
+         * Pretend we do RGB32.  This is here on the assumption that the
+         * upper layer will reformat RGB444 appropriately.
+         *
+         * The entire purpose for this thing's existence is to enable easy
+         * display of RGB444 for debugging purposes.  It will come out soon.
+         */
+        {
+                .desc           = "RGB32 (faked)",
+                .pixelformat    = V4L2_PIX_FMT_RGB32,
+                .regs           = ov7670_fmt_rgb444,
+        },
+};
+#define N_OV7670_FMTS (sizeof(ov7670_formats)/sizeof(ov7670_formats[0]))
+
+/*
+ * All formats we support are 2 bytes/pixel.
+ */
+#define BYTES_PER_PIXEL 2
+
+/*
+ * Then there is the issue of window sizes.  Try to capture the info here.
+ */
+static struct ov7670_win_size {
+        int     width;
+        int     height;
+        unsigned char com7_bit;
+        int     hstart;         /* Start/stop values for the camera.  Note */
+        int     hstop;          /* that they do not always make complete */
+        int     vstart;         /* sense to humans, but evidently the sensor */
+        int     vstop;          /* will do the right thing... */
+/* h/vref stuff */
+} ov7670_win_sizes[] = {
+        /* VGA */
+        {
+                .width          = VGA_WIDTH,
+                .height         = VGA_HEIGHT,
+                .com7_bit       = COM7_FMT_VGA,
+                .hstart         = 158,          /* These values from */
+                .hstop          =  14,          /* Omnivision */
+                .vstart         =  10,
+                .vstop          = 490,
+        },
+        /* CIF */
+        {
+                .width          = CIF_WIDTH,
+                .height         = CIF_HEIGHT,
+                .com7_bit       = COM7_FMT_CIF,
+                .hstart         = 170,          /* Empirically determined */
+                .hstop          =  90,
+                .vstart         =  14,
+                .vstop          = 494,
+        },
+        /* QVGA */
+        {
+                .width          = QVGA_WIDTH,
+                .height         = QVGA_HEIGHT,
+                .com7_bit       = COM7_FMT_QVGA,
+                .hstart         = 164,          /* Empirically determined */
+                .hstop          =  20,
+                .vstart         =  14,
+                .vstop          = 494,
+        },
+};
+
+#define N_WIN_SIZES (sizeof(ov7670_win_sizes)/sizeof(ov7670_win_sizes[0]))
+
+
+/*
+ * Store a set of start/stop values into the camera.
+ */
+static int ov7670_set_hw(struct i2c_client *client, int hstart, int hstop,
+                int vstart, int vstop)
+{
+        int ret;
+        unsigned char v;
+/*
+ * Horizontal: 11 bits, top 8 live in hstart and hstop.  Bottom 3 of
+ * hstart are in href[2:0], bottom 3 of hstop in href[5:3].  There is
+ * a mystery "edge offset" value in the top two bits of href.
+ */
+        ret =  ov7670_write(client, REG_HSTART, (hstart >> 3) & 0xff);
+        ret += ov7670_write(client, REG_HSTOP, (hstop >> 3) & 0xff);
+        ret += ov7670_read(client, REG_HREF, &v);
+        v = (v & 0xc0) | ((hstop & 0x7) << 3) | (hstart & 0x7);
+        msleep(10);
+        ret += ov7670_write(client, REG_HREF, v);
+/*
+ * Vertical: similar arrangement, but only 10 bits.
+ */
+        ret += ov7670_write(client, REG_VSTART, (vstart >> 2) & 0xff);
+        ret += ov7670_write(client, REG_VSTOP, (vstop >> 2) & 0xff);
+        ret += ov7670_read(client, REG_VREF, &v);
+        v = (v & 0xf0) | ((vstop & 0x3) << 2) | (vstart & 0x3);
+        msleep(10);
+        ret += ov7670_write(client, REG_VREF, v);
+        return ret;
+}
+
+
+static int ov7670_enum_fmt(struct i2c_client *c, struct v4l2_fmtdesc *fmt)
+{
+        struct ov7670_format_struct *ofmt;
+
+        if (fmt->index >= N_OV7670_FMTS)
+                return -EINVAL;
+
+        ofmt = ov7670_formats + fmt->index;
+        fmt->flags = 0;
+        strcpy(fmt->description, ofmt->desc);
+        fmt->pixelformat = ofmt->pixelformat;
+        return 0;
+}
+
+
+static int ov7670_try_fmt(struct i2c_client *c, struct v4l2_format *fmt,
+                struct ov7670_format_struct **ret_fmt,
+                struct ov7670_win_size **ret_wsize)
+{
+        int index;
+        struct ov7670_win_size *wsize;
+        struct v4l2_pix_format *pix = &fmt->fmt.pix;
+
+        for (index = 0; index < N_OV7670_FMTS; index++)
+                if (ov7670_formats[index].pixelformat == pix->pixelformat)
+                        break;
+        if (index >= N_OV7670_FMTS)
+                return -EINVAL;
+        if (ret_fmt != NULL)
+                *ret_fmt = ov7670_formats + index;
+        /*
+         * Fields: the OV devices claim to be progressive.
+         */
+        if (pix->field == V4L2_FIELD_ANY)
+                pix->field = V4L2_FIELD_NONE;
+        else if (pix->field != V4L2_FIELD_NONE)
+                return -EINVAL;
+        /*
+         * Round requested image size down to the nearest
+         * we support, but not below the smallest.
+         */
+        for (wsize = ov7670_win_sizes; wsize < ov7670_win_sizes + N_WIN_SIZES;
+             wsize++)
+                if (pix->width >= wsize->width && pix->height >= wsize->height)
+                        break;
+        if (wsize > ov7670_win_sizes + N_WIN_SIZES)
+                wsize--;   /* Take the smallest one */
+        if (ret_wsize != NULL)
+                *ret_wsize = wsize;
+        /*
+         * Note the size we'll actually handle.
+         */
+        pix->width = wsize->width;
+        pix->height = wsize->height;
+        pix->bytesperline = pix->width*BYTES_PER_PIXEL;
+        if (pix->pixelformat == V4L2_PIX_FMT_RGB32)
+                pix->bytesperline *= 2;
+        pix->sizeimage = pix->height*pix->bytesperline;
+        return 0;
+
+}
+
+/*
+ * Set a format.
+ */
+static int ov7670_s_fmt(struct i2c_client *c, struct v4l2_format *fmt)
+{
+        int ret;
+        struct ov7670_format_struct *ovfmt;
+        struct ov7670_win_size *wsize;
+        unsigned char com7;
+
+        ret = ov7670_try_fmt(c, fmt, &ovfmt, &wsize);
+        if (ret)
+                return ret;
+        /*
+         * COM7 is a pain in the ass, it doesn't like to be read then
+         * quickly written afterward.  But we have everything we need
+         * to set it absolutely here, as long as the format-specific
+         * register sets list it first.
+         */
+        com7 = ovfmt->regs[0].value;
+        com7 |= wsize->com7_bit;
+        ov7670_write(c, REG_COM7, com7);
+        /*
+         * Now write the rest of the array.  Also store start/stops
+         */
+        ov7670_write_array(c, ovfmt->regs + 1);
+        ov7670_set_hw(c, wsize->hstart, wsize->hstop, wsize->vstart,
+                        wsize->vstop);
+        return 0;
+}
+
+/*
+ * Code for dealing with controls.
+ */
+
+/*
+ * Some weird registers seem to store values in a sign/magnitude format!
+ */
+static unsigned char ov7670_sm_to_abs(unsigned char v)
+{
+        if ((v & 0x80) == 0)
+                return v + 128;
+        else
+                return 128 - (v & 0x7f);
+}
+
+
+static unsigned char ov7670_abs_to_sm(unsigned char v)
+{
+        if (v > 127)
+                return v & 0x7f;
+        else
+                return (128 - v) | 0x80;
+}
+
+static int ov7670_t_brightness(struct i2c_client *client, unsigned char value)
+{
+        unsigned char com8;
+        int ret;
+
+        ov7670_read(client, REG_COM8, &com8);
+        com8 &= ~COM8_AEC;
+        ov7670_write(client, REG_COM8, com8);
+        value = ov7670_abs_to_sm(value);
+        ret = ov7670_write(client, REG_BRIGHT, value);
+        return ret;
+}
+
+static int ov7670_q_brightness(struct i2c_client *client, unsigned char *value)
+{
+        int ret;
+        ret = ov7670_read(client, REG_BRIGHT, value);
+        *value = ov7670_sm_to_abs(*value);
+        return ret;
+}
+
+static int ov7670_t_contrast(struct i2c_client *client, unsigned char value)
+{
+        return ov7670_write(client, REG_CONTRAS, value);
+}
+
+static int ov7670_q_contrast(struct i2c_client *client, unsigned char *value)
+{
+        return ov7670_read(client, REG_CONTRAS, value);
+}
+
+static int ov7670_q_hflip(struct i2c_client *client, unsigned char *value)
+{
+        int ret;
+        unsigned char v;
+
+        ret = ov7670_read(client, REG_MVFP, &v);
+        *value = (v & MVFP_MIRROR) == MVFP_MIRROR;
+        return ret;
+}
+
+
+static int ov7670_t_hflip(struct i2c_client *client, unsigned char value)
+{
+        unsigned char v;
+        int ret;
+
+        ret = ov7670_read(client, REG_MVFP, &v);
+        if (value)
+                v |= MVFP_MIRROR;
+        else
+                v &= ~MVFP_MIRROR;
+        msleep(10);  /* FIXME */
+        ret += ov7670_write(client, REG_MVFP, v);
+        return ret;
+}
+
+
+
+static int ov7670_q_vflip(struct i2c_client *client, unsigned char *value)
+{
+        int ret;
+        unsigned char v;
+
+        ret = ov7670_read(client, REG_MVFP, &v);
+        *value = (v & MVFP_FLIP) == MVFP_FLIP;
+        return ret;
+}
+
+
+static int ov7670_t_vflip(struct i2c_client *client, unsigned char value)
+{
+        unsigned char v;
+        int ret;
+
+        ret = ov7670_read(client, REG_MVFP, &v);
+        if (value)
+                v |= MVFP_FLIP;
+        else
+                v &= ~MVFP_FLIP;
+        msleep(10);  /* FIXME */
+        ret += ov7670_write(client, REG_MVFP, v);
+        return ret;
+}
+
+
+static struct ov7670_control {
+        struct v4l2_queryctrl qc;
+        int (*query)(struct i2c_client *c, unsigned char *value);
+        int (*tweak)(struct i2c_client *c, unsigned char value);
+} ov7670_controls[] =
+{
+        {
+                .qc = {
+                        .id = V4L2_CID_BRIGHTNESS,
+                        .type = V4L2_CTRL_TYPE_INTEGER,
+                        .name = "Brightness",
+                        .minimum = 0,
+                        .maximum = 255,
+                        .step = 1,
+                        .default_value = 0x80,
+                        .flags = V4L2_CTRL_FLAG_SLIDER
+                },
+                .tweak = ov7670_t_brightness,
+                .query = ov7670_q_brightness,
+        },
+        {
+                .qc = {
+                        .id = V4L2_CID_CONTRAST,
+                        .type = V4L2_CTRL_TYPE_INTEGER,
+                        .name = "Contrast",
+                        .minimum = 0,
+                        .maximum = 127,
+                        .step = 1,
+                        .default_value = 0x40,   /* XXX ov7670 spec */
+                        .flags = V4L2_CTRL_FLAG_SLIDER
+                },
+                .tweak = ov7670_t_contrast,
+                .query = ov7670_q_contrast,
+        },
+        {
+                .qc = {
+                        .id = V4L2_CID_VFLIP,
+                        .type = V4L2_CTRL_TYPE_BOOLEAN,
+                        .name = "Vertical flip",
+                        .minimum = 0,
+                        .maximum = 1,
+                        .step = 1,
+                        .default_value = 0,
+                },
+                .tweak = ov7670_t_vflip,
+                .query = ov7670_q_vflip,
+        },
+        {
+                .qc = {
+                        .id = V4L2_CID_HFLIP,
+                        .type = V4L2_CTRL_TYPE_BOOLEAN,
+                        .name = "Horizontal mirror",
+                        .minimum = 0,
+                        .maximum = 1,
+                        .step = 1,
+                        .default_value = 0,
+                },
+                .tweak = ov7670_t_hflip,
+                .query = ov7670_q_hflip,
+        },
+};
+#define N_CONTROLS (sizeof(ov7670_controls)/sizeof(ov7670_controls[0]))
+
+static struct ov7670_control *ov7670_find_control(__u32 id)
+{
+        int i;
+
+        for (i = 0; i < N_CONTROLS; i++)
+                if (ov7670_controls[i].qc.id == id)
+                        return ov7670_controls + i;
+        return NULL;
+}
+
+
+static int ov7670_queryctrl(struct i2c_client *client,
+                struct v4l2_queryctrl *qc)
+{
+        struct ov7670_control *ctrl = ov7670_find_control(qc->id);
+
+        if (ctrl == NULL)
+                return -EINVAL;
+        *qc = ctrl->qc;
+        return 0;
+}
+
+static int ov7670_g_ctrl(struct i2c_client *client, struct v4l2_control *ctrl)
+{
+        struct ov7670_control *octrl = ov7670_find_control(ctrl->id);
+        int ret;
+        unsigned char v;
+
+        if (octrl == NULL)
+                return -EINVAL;
+        ret = octrl->query(client, &v);
+        if (ret >= 0) {
+                ctrl->value = v;
+                return 0;
+        }
+        return ret;
+}
+
+static int ov7670_s_ctrl(struct i2c_client *client, struct v4l2_control *ctrl)
+{
+        struct ov7670_control *octrl = ov7670_find_control(ctrl->id);
+
+        if (octrl == NULL)
+                return -EINVAL;
+        return octrl->tweak(client, ctrl->value);
+}
+
+
+
+
+
+
+
+/*
+ * Basic i2c stuff.
+ */
+static struct i2c_driver ov7670_driver;
+
+static int ov7670_attach(struct i2c_adapter *adapter)
+{
+        int ret;
+        struct i2c_client *client;
+
+        printk(KERN_ERR "ov7670 attach, id = %d\n", adapter->id);
+        /*
+         * For now: only deal with adapters we recognize.
+         */
+        if (adapter->id != I2C_HW_SMBUS_CAFE)
+                return -ENODEV;
+
+        printk(KERN_ERR "ov7670 accepting\n");
+        client = kzalloc(sizeof (struct i2c_client), GFP_KERNEL);
+        if (! client)
+                return -ENOMEM;
+        client->adapter = adapter;
+        client->addr = OV7670_I2C_ADDR;
+        client->driver = &ov7670_driver,
+        strcpy(client->name, "OV7670");
+        /* Do we need clientdata? */
+
+        /*
+         * Make sure it's an ov7670
+         */
+        ret = ov7670_detect(client);
+        printk(KERN_ERR "detect result is %d\n", ret);
+        if (ret)
+                goto out_free;
+        i2c_attach_client(client);
+        return 0;
+
+  out_free:
+        kfree(client);
+        return ret;
+}
+
+
+static int ov7670_detach(struct i2c_client *client)
+{
+        i2c_detach_client(client);
+        kfree(client);
+        return 0;
+}
+
+
+static int ov7670_command(struct i2c_client *client, unsigned int cmd,
+                void *arg)
+{
+        switch (cmd) {
+        case VIDIOC_INT_G_CHIP_IDENT:
+                * (enum v4l2_chip_ident *) arg = V4L2_IDENT_OV7670;
+                return 0;
+
+        case VIDIOC_INT_RESET:
+                ov7670_reset(client);
+                return 0;
+
+        case VIDIOC_INT_INIT:
+                return ov7670_init(client);
+
+        case VIDIOC_ENUM_FMT:
+                return ov7670_enum_fmt(client, (struct v4l2_fmtdesc *) arg);
+        case VIDIOC_TRY_FMT:
+                return ov7670_try_fmt(client, (struct v4l2_format *) arg, NULL, NULL);
+        case VIDIOC_S_FMT:
+                return ov7670_s_fmt(client, (struct v4l2_format *) arg);
+        case VIDIOC_QUERYCTRL:
+                return ov7670_queryctrl(client, (struct v4l2_queryctrl *) arg);
+        case VIDIOC_S_CTRL:
+                return ov7670_s_ctrl(client, (struct v4l2_control *) arg);
+        case VIDIOC_G_CTRL:
+                return ov7670_g_ctrl(client, (struct v4l2_control *) arg);
+        /* Todo:
+           g/s_parm
+           initialization
+        */
+        }
+        return -EINVAL;
+}
+
+
+
+static struct i2c_driver ov7670_driver = {
+        .driver = {
+                .name = "ov7670",
+        },
+        .id             = I2C_DRIVERID_OV7670,
+        .class          = I2C_CLASS_CAM_DIGITAL,
+        .attach_adapter = ov7670_attach,
+        .detach_client  = ov7670_detach,
+        .command        = ov7670_command,
+};
+
+
+/*
+ * Module initialization
+ */
+static int __init ov7670_mod_init(void)
+{
+        printk(KERN_NOTICE "OmniVision ov7670 sensor driver, at your service\n");
+        return i2c_add_driver(&ov7670_driver);
+}
+
+static void __exit ov7670_mod_exit(void)
+{
+        i2c_del_driver(&ov7670_driver);
+}
+
+module_init(ov7670_mod_init);
+module_exit(ov7670_mod_exit);