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[media] ov7670: allow configuration of image size, clock speed, and I…
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…/O method

These parameters need to be configurable based on the host system.
They can now be communicated through the s_config call.

The old CONFIG_OLPC_XO_1 selector was not correct; this kind of
arrangement wouldn't allow for a universal kernel that would work on both
laptops.

Certain parts of the probe routine had to be moved later (into s_config),
because we can't do any I/O until we know which I/O method has been
selected through this mechanism.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Daniel Drake authored and Mauro Carvalho Chehab committed Oct 23, 2010
1 parent f8c6127 commit 75e2bda
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Showing 2 changed files with 115 additions and 38 deletions.
133 changes: 95 additions & 38 deletions drivers/media/video/ov7670.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
#include <media/v4l2-chip-ident.h>
#include <media/v4l2-mediabus.h>

#include "ov7670.h"

MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net>");
MODULE_DESCRIPTION("A low-level driver for OmniVision ov7670 sensors");
Expand All @@ -42,11 +43,6 @@ MODULE_PARM_DESC(debug, "Debug level (0-1)");
#define QCIF_WIDTH 176
#define QCIF_HEIGHT 144

/*
* Our nominal (default) frame rate.
*/
#define OV7670_FRAME_RATE 30

/*
* The 7670 sits on i2c with ID 0x42
*/
Expand Down Expand Up @@ -198,7 +194,11 @@ struct ov7670_info {
struct ov7670_format_struct *fmt; /* Current format */
unsigned char sat; /* Saturation value */
int hue; /* Hue value */
int min_width; /* Filter out smaller sizes */
int min_height; /* Filter out smaller sizes */
int clock_speed; /* External clock speed (MHz) */
u8 clkrc; /* Clock divider value */
bool use_smbus; /* Use smbus I/O instead of I2C */
};

static inline struct ov7670_info *to_state(struct v4l2_subdev *sd)
Expand Down Expand Up @@ -415,8 +415,7 @@ static struct regval_list ov7670_fmt_raw[] = {
* ov7670 is not really an SMBUS device, though, so the communication
* is not always entirely reliable.
*/
#ifdef CONFIG_OLPC_XO_1
static int ov7670_read(struct v4l2_subdev *sd, unsigned char reg,
static int ov7670_read_smbus(struct v4l2_subdev *sd, unsigned char reg,
unsigned char *value)
{
struct i2c_client *client = v4l2_get_subdevdata(sd);
Expand All @@ -431,7 +430,7 @@ static int ov7670_read(struct v4l2_subdev *sd, unsigned char reg,
}


static int ov7670_write(struct v4l2_subdev *sd, unsigned char reg,
static int ov7670_write_smbus(struct v4l2_subdev *sd, unsigned char reg,
unsigned char value)
{
struct i2c_client *client = v4l2_get_subdevdata(sd);
Expand All @@ -442,11 +441,10 @@ static int ov7670_write(struct v4l2_subdev *sd, unsigned char reg,
return ret;
}

#else /* ! CONFIG_OLPC_XO_1 */
/*
* On most platforms, we'd rather do straight i2c I/O.
*/
static int ov7670_read(struct v4l2_subdev *sd, unsigned char reg,
static int ov7670_read_i2c(struct v4l2_subdev *sd, unsigned char reg,
unsigned char *value)
{
struct i2c_client *client = v4l2_get_subdevdata(sd);
Expand Down Expand Up @@ -479,7 +477,7 @@ static int ov7670_read(struct v4l2_subdev *sd, unsigned char reg,
}


static int ov7670_write(struct v4l2_subdev *sd, unsigned char reg,
static int ov7670_write_i2c(struct v4l2_subdev *sd, unsigned char reg,
unsigned char value)
{
struct i2c_client *client = v4l2_get_subdevdata(sd);
Expand All @@ -498,8 +496,26 @@ static int ov7670_write(struct v4l2_subdev *sd, unsigned char reg,
msleep(5); /* Wait for reset to run */
return ret;
}
#endif /* CONFIG_OLPC_XO_1 */

static int ov7670_read(struct v4l2_subdev *sd, unsigned char reg,
unsigned char *value)
{
struct ov7670_info *info = to_state(sd);
if (info->use_smbus)
return ov7670_read_smbus(sd, reg, value);
else
return ov7670_read_i2c(sd, reg, value);
}

static int ov7670_write(struct v4l2_subdev *sd, unsigned char reg,
unsigned char value)
{
struct ov7670_info *info = to_state(sd);
if (info->use_smbus)
return ov7670_write_smbus(sd, reg, value);
else
return ov7670_write_i2c(sd, reg, value);
}

/*
* Write a list of register settings; ff/ff stops the process.
Expand Down Expand Up @@ -854,7 +870,7 @@ static int ov7670_g_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms)
memset(cp, 0, sizeof(struct v4l2_captureparm));
cp->capability = V4L2_CAP_TIMEPERFRAME;
cp->timeperframe.numerator = 1;
cp->timeperframe.denominator = OV7670_FRAME_RATE;
cp->timeperframe.denominator = info->clock_speed;
if ((info->clkrc & CLK_EXT) == 0 && (info->clkrc & CLK_SCALE) > 1)
cp->timeperframe.denominator /= (info->clkrc & CLK_SCALE);
return 0;
Expand All @@ -875,14 +891,14 @@ static int ov7670_s_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms)
if (tpf->numerator == 0 || tpf->denominator == 0)
div = 1; /* Reset to full rate */
else
div = (tpf->numerator*OV7670_FRAME_RATE)/tpf->denominator;
div = (tpf->numerator * info->clock_speed) / tpf->denominator;
if (div == 0)
div = 1;
else if (div > CLK_SCALE)
div = CLK_SCALE;
info->clkrc = (info->clkrc & 0x80) | div;
tpf->numerator = 1;
tpf->denominator = OV7670_FRAME_RATE/div;
tpf->denominator = info->clock_speed / div;
return ov7670_write(sd, REG_CLKRC, info->clkrc);
}

Expand Down Expand Up @@ -912,14 +928,30 @@ static int ov7670_enum_frameintervals(struct v4l2_subdev *sd,
static int ov7670_enum_framesizes(struct v4l2_subdev *sd,
struct v4l2_frmsizeenum *fsize)
{
struct ov7670_info *info = to_state(sd);
int i;
int num_valid = -1;
__u32 index = fsize->index;
if (index >= N_WIN_SIZES)
return -EINVAL;

fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
fsize->discrete.width = ov7670_win_sizes[index].width;
fsize->discrete.height = ov7670_win_sizes[index].height;
return 0;
/*
* If a minimum width/height was requested, filter out the capture
* windows that fall outside that.
*/
for (i = 0; i < N_WIN_SIZES; i++) {
struct ov7670_win_size *win = &ov7670_win_sizes[index];
if (info->min_width && win->width < info->min_width)
continue;
if (info->min_height && win->height < info->min_height)
continue;
if (index == ++num_valid) {
fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
fsize->discrete.width = win->width;
fsize->discrete.height = win->height;
return 0;
}
}

return -EINVAL;
}

/*
Expand Down Expand Up @@ -1417,6 +1449,47 @@ static int ov7670_g_chip_ident(struct v4l2_subdev *sd,
return v4l2_chip_ident_i2c_client(client, chip, V4L2_IDENT_OV7670, 0);
}

static int ov7670_s_config(struct v4l2_subdev *sd, int dumb, void *data)
{
struct i2c_client *client = v4l2_get_subdevdata(sd);
struct ov7670_config *config = data;
struct ov7670_info *info = to_state(sd);
int ret;

info->clock_speed = 30; /* default: a guess */

/*
* Must apply configuration before initializing device, because it
* selects I/O method.
*/
if (config) {
info->min_width = config->min_width;
info->min_height = config->min_height;
info->use_smbus = config->use_smbus;

if (config->clock_speed)
info->clock_speed = config->clock_speed;
}

/* Make sure it's an ov7670 */
ret = ov7670_detect(sd);
if (ret) {
v4l_dbg(1, debug, client,
"chip found @ 0x%x (%s) is not an ov7670 chip.\n",
client->addr << 1, client->adapter->name);
kfree(info);
return ret;
}
v4l_info(client, "chip found @ 0x%02x (%s)\n",
client->addr << 1, client->adapter->name);

info->fmt = &ov7670_formats[0];
info->sat = 128; /* Review this */
info->clkrc = info->clock_speed / 30;

return 0;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int ov7670_g_register(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg)
{
Expand Down Expand Up @@ -1455,6 +1528,7 @@ static const struct v4l2_subdev_core_ops ov7670_core_ops = {
.s_ctrl = ov7670_s_ctrl,
.queryctrl = ov7670_queryctrl,
.reset = ov7670_reset,
.s_config = ov7670_s_config,
.init = ov7670_init,
#ifdef CONFIG_VIDEO_ADV_DEBUG
.g_register = ov7670_g_register,
Expand Down Expand Up @@ -1484,30 +1558,13 @@ static int ov7670_probe(struct i2c_client *client,
{
struct v4l2_subdev *sd;
struct ov7670_info *info;
int ret;

info = kzalloc(sizeof(struct ov7670_info), GFP_KERNEL);
if (info == NULL)
return -ENOMEM;
sd = &info->sd;
v4l2_i2c_subdev_init(sd, client, &ov7670_ops);

/* Make sure it's an ov7670 */
ret = ov7670_detect(sd);
if (ret) {
v4l_dbg(1, debug, client,
"chip found @ 0x%x (%s) is not an ov7670 chip.\n",
client->addr << 1, client->adapter->name);
kfree(info);
return ret;
}
v4l_info(client, "chip found @ 0x%02x (%s)\n",
client->addr << 1, client->adapter->name);

info->fmt = &ov7670_formats[0];
info->sat = 128; /* Review this */
info->clkrc = 1; /* 30fps */

return 0;
}

Expand Down
20 changes: 20 additions & 0 deletions drivers/media/video/ov7670.h
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
/*
* A V4L2 driver for OmniVision OV7670 cameras.
*
* Copyright 2010 One Laptop Per Child
*
* This file may be distributed under the terms of the GNU General
* Public License, version 2.
*/

#ifndef __OV7670_H
#define __OV7670_H

struct ov7670_config {
int min_width; /* Filter out smaller sizes */
int min_height; /* Filter out smaller sizes */
int clock_speed; /* External clock speed (MHz) */
bool use_smbus; /* Use smbus I/O instead of I2C */
};

#endif

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