On Wed, 17 Jun 2009, Jonathan Cameron wrote:
> This is purely for info of anyone else wanting to use the ov7670
> with Guennadi's recent work on converted soc-camera to v4l2-subdevs.
>
> It may not be completely minimal, but it's letting me take pictures ;)
Cool, I like it! Not the pictures, but the fact that the required patch
turned out to be so small. Of course, you understand this is not what
we'll eventually commit, but, I think, this is a good start. In principle,
if a device has all parameters fixed, there's no merit in trying to set
them.
> Couple of minor queries:
>
> Currently it is assumed that there is a means of telling the chip to
> use particular bus params. In the case of this one it doesn't support
> anything other than 8 bit. Stuff may get added down the line, but
> in meantime does anyone mind if we make icd->ops->set_bus_param
> optional in soc-camera?
struct soc_camera_ops will disappear completely anyway, and we don't know
yet what the v4l2-subdev counterpart will look like.
> Is there any reason (or advantage) in not specifying the i2c address
> in the driver?
Some i2c devices can be configured to respond to one of several i2c
addresses.
> Or for that matter why the address is right shifted by
> 1 in:
>
> v4l_info(client, "chip found @ 0x%02x (%s)\n",
> client->addr << 1, client->adapter->name);
>
> Admittedly the data sheet uses an 'unusual' convention for the
> address (separate write and read address which correspond to
> a single address of 0x21 with the relevant write bit set as
> appropriate).
That's exactly the reason, I think. Many (or most?) datasheets specify i2c
addresses which are a double of Linux i2c address. IIRC this is just a
Linux convention to use the shifted address.
> As ever any comments welcome. Thanks to Guennadi Liakhovetski
> for his soc-camera work and Hans Verkuil for conversion of the
> ov7670 to soc-dev.
>
> Tested against a merge of todays v4l-next tree and Linus' current
> with the minor pxa-camera bug I posted earlier fixed and Guennadi's
> extensive patch set applied (this requires a few hand merges, but
> nothing too nasty).
Good to know.
A couple of comments:
> diff --git a/include/media/ov7670_soc.h b/include/media/ov7670_soc.h
> new file mode 100644
> index 0000000..2f264b2
> --- /dev/null
> +++ b/include/media/ov7670_soc.h
> @@ -0,0 +1,21 @@
> +/* ov7670_soc Camera
> + *
> + * Copyright (C) 2009 Jonathan Cameron <ji...@cam.ac.uk>
> + *
> + * 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.
> + */
> +
> +#ifndef __OV7670_SOC_H__
> +#define __OV7670_SOC_H__
> +
> +#include <media/soc_camera.h>
> +
> +struct ov7670_soc_camera_info {
> + int gpio_pwr;
> + int gpio_reset;
You should not need these GPIOs...
> + struct soc_camera_link link;
> +};
> +
> +#endif
> diff --git a/drivers/media/video/ov7670.c b/drivers/media/video/ov7670.c
> index 0e2184e..51d432e 100644
> --- a/drivers/media/video/ov7670.c
> +++ b/drivers/media/video/ov7670.c
> @@ -19,7 +19,14 @@
> #include <media/v4l2-chip-ident.h>
> #include <media/v4l2-i2c-drv.h>
>
> +#define OV7670_SOC
>
> +
> +#ifdef OV7670_SOC
> +#include <media/ov7670_soc.h>
> +#include <media/soc_camera.h>
> +#include <linux/gpio.h>
...this header...
> +#endif /* OV7670_SOC */
> MODULE_AUTHOR("Jonathan Corbet <cor...@lwn.net>");
> MODULE_DESCRIPTION("A low-level driver for OmniVision ov7670 sensors");
> MODULE_LICENSE("GPL");
> @@ -1239,19 +1246,94 @@ static const struct v4l2_subdev_ops ov7670_ops = {
> };
>
> /* ----------------------------------------------------------------------- */
> +#ifdef OV7670_SOC
> +
> +static unsigned long ov7670_soc_query_bus_param(struct soc_camera_device
> *icd)
> +{
> + struct soc_camera_link *icl = to_soc_camera_link(icd);
> +
> + unsigned long flags = SOCAM_PCLK_SAMPLE_RISING | SOCAM_MASTER |
> + SOCAM_VSYNC_ACTIVE_HIGH | SOCAM_HSYNC_ACTIVE_HIGH |
> + SOCAM_DATAWIDTH_8 | SOCAM_DATA_ACTIVE_HIGH;
> +
> + return soc_camera_apply_sensor_flags(icl, flags);
> +}
> +/* This device only supports one bus option */
> +static int ov7670_soc_set_bus_param(struct soc_camera_device *icd,
> + unsigned long flags)
> +{
> + return 0;
> +}
> +
> +static struct soc_camera_ops ov7670_soc_ops = {
> + .set_bus_param = ov7670_soc_set_bus_param,
> + .query_bus_param = ov7670_soc_query_bus_param,
> +};
> +
> +#define SETFOURCC(type) .name = (#type), .fourcc = (V4L2_PIX_FMT_ ## type)
> +static const struct soc_camera_data_format ov7670_soc_fmt_lists[] = {
> + {
> + SETFOURCC(YUYV),
> + .depth = 16,
> + .colorspace = V4L2_COLORSPACE_JPEG,
> + }, {
> + SETFOURCC(RGB565),
> + .depth = 16,
> + .colorspace = V4L2_COLORSPACE_SRGB,
> + },
> +};
>
> +#endif
> static int ov7670_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> +#ifdef OV7670_SOC
> + struct soc_camera_device *icd = client->dev.platform_data;
> + struct soc_camera_link *icl;
> + struct ov7670_soc_camera_info *board_info;
> +#endif
> struct v4l2_subdev *sd;
> struct ov7670_info *info;
> +
> int ret;
>
> +#ifdef OV7670_SOC
> + icl = to_soc_camera_link(icd);
> + if (!icl)
> + return -EINVAL;
> + board_info = container_of(icl, struct ov7670_soc_camera_info, link);
> +
> + gpio_request(board_info->gpio_reset, "ov7670 soc reset");
> + gpio_request(board_info->gpio_pwr, "ov7670 soc power");
> +
> + /* reset high for normal mode */
> + gpio_direction_output(board_info->gpio_reset, 1);
> + /* power down normal mode. */
> + gpio_direction_output(board_info->gpio_pwr, 0);
> + /* perform a hard reset as per tinyos code */
> + gpio_set_value(board_info->gpio_pwr, 1);
> + gpio_set_value(board_info->gpio_reset, 1);
> + mdelay(2);
> + gpio_set_value(board_info->gpio_pwr, 0);
> + gpio_set_value(board_info->gpio_reset, 0);
> + mdelay(2);
> + gpio_set_value(board_info->gpio_reset, 1);
> + mdelay(5);
> +#endif
...and this switching. All this should be done in struct soc_camera_link
.power() and .reset() methods in your platform code.
> info = kzalloc(sizeof(struct ov7670_info), GFP_KERNEL);
> if (info == NULL)
> return -ENOMEM;
> + /* JIC; whole load of reset code may be needed */
> +
> sd = &info->sd;
> v4l2_i2c_subdev_init(sd, client, &ov7670_ops);
> +#ifdef OV7670_SOC
> + icd->ops = &ov7670_soc_ops;
> + icd->rect_max.width = VGA_WIDTH;
> + icd->rect_max.height = VGA_HEIGHT;
> + icd->formats = ov7670_soc_fmt_lists;
> + icd->num_formats = ARRAY_SIZE(ov7670_soc_fmt_lists);
> +#endif
>
> /* Make sure it's an ov7670 */
> ret = ov7670_detect(sd);
> @@ -1282,7 +1364,11 @@ static int ov7670_remove(struct i2c_client *client)
> }
>
> static const struct i2c_device_id ov7670_id[] = {
> - { "ov7670", 0 },
> +#ifdef OV7670_SOC
> + { "ov7670", 0x21 },
> +#else
> + { "ov7670", 0 },
> +#endif
And you don't need this, just specify the address in platform code.
> { }
> };
> MODULE_DEVICE_TABLE(i2c, ov7670_id);
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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