linux-kernel - Re: [PATCH 1/2] media: i2c: ov7670: Extend match support for OF tables

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Message-ID: <6yvrergos76akx42x33owvxwlye5nsgp6tgywqkfzcbmiaywhc@vx6ubzvrmtq2>
Date:   Mon, 11 Sep 2023 10:08:22 +0200
From:   Jacopo Mondi <jacopo.mondi@...asonboard.com>
To:     Biju Das <biju.das.jz@...renesas.com>
Cc:     Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Biju Das <biju.das.au@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 1/2] media: i2c: ov7670: Extend match support for OF
 tables

Hi Biju

On Sun, Sep 10, 2023 at 04:00:32PM +0100, Biju Das wrote:
> The driver has an OF match table, still, it uses an ID lookup table for
> retrieving match data. Currently, the driver is working on the
> assumption that an I2C device registered via OF will always match a
> legacy I2C device ID. The correct approach is to have an OF device ID
> table using i2c_get_match_data() if the devices are registered via OF/ID.
>
> Unify the OF/ID table by using struct ov7670_devtype as match data for
> both these tables and replace the ID lookup table for the match data by
> i2c_get_match_data().
>
> Split the array ov7670_devdata[] as individual variables, and
> make lines shorter by referring to e.g. &ov7670_devdata instead of
> &ov7670_devdata[MODEL_OV7670].
>
> Drop enum ov7670_model as there is no user.
>
> While at it, remove the trailing comma in the terminator entry for the OF
> table making code robust against (theoretical) misrebases or other similar
> things where the new entry goes _after_ the termination without the
> compiler noticing.
>
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
> ---
>  drivers/media/i2c/ov7670.c | 47 ++++++++++++++++----------------------
>  1 file changed, 20 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> index 2f55491ef571..644457e6993d 100644
> --- a/drivers/media/i2c/ov7670.c
> +++ b/drivers/media/i2c/ov7670.c
> @@ -186,11 +186,6 @@ MODULE_PARM_DESC(debug, "Debug level (0-1)");
>  #define REG_HAECC7	0xaa	/* Hist AEC/AGC control 7 */
>  #define REG_BD60MAX	0xab	/* 60hz banding step limit */
>
> -enum ov7670_model {
> -	MODEL_OV7670 = 0,
> -	MODEL_OV7675,
> -};
> -
>  struct ov7670_win_size {
>  	int	width;
>  	int	height;
> @@ -1774,21 +1769,6 @@ static const struct v4l2_subdev_internal_ops ov7670_subdev_internal_ops = {
>
>  /* ----------------------------------------------------------------------- */
>
> -static const struct ov7670_devtype ov7670_devdata[] = {
> -	[MODEL_OV7670] = {
> -		.win_sizes = ov7670_win_sizes,
> -		.n_win_sizes = ARRAY_SIZE(ov7670_win_sizes),
> -		.set_framerate = ov7670_set_framerate_legacy,
> -		.get_framerate = ov7670_get_framerate_legacy,
> -	},
> -	[MODEL_OV7675] = {
> -		.win_sizes = ov7675_win_sizes,
> -		.n_win_sizes = ARRAY_SIZE(ov7675_win_sizes),
> -		.set_framerate = ov7675_set_framerate,
> -		.get_framerate = ov7675_get_framerate,
> -	},
> -};
> -
>  static int ov7670_init_gpio(struct i2c_client *client, struct ov7670_info *info)
>  {
>  	info->pwdn_gpio = devm_gpiod_get_optional(&client->dev, "powerdown",
> @@ -1849,7 +1829,6 @@ static int ov7670_parse_dt(struct device *dev,
>
>  static int ov7670_probe(struct i2c_client *client)
>  {
> -	const struct i2c_device_id *id = i2c_client_get_device_id(client);
>  	struct v4l2_fract tpf;
>  	struct v4l2_subdev *sd;
>  	struct ov7670_info *info;
> @@ -1923,7 +1902,7 @@ static int ov7670_probe(struct i2c_client *client)
>  	v4l_info(client, "chip found @ 0x%02x (%s)\n",
>  			client->addr << 1, client->adapter->name);
>
> -	info->devtype = &ov7670_devdata[id->driver_data];
> +	info->devtype = i2c_get_match_data(client);

I was about to complain this function is not used, but then I noticed
you just introduced it, so this is like the first user!


>  	info->fmt = &ov7670_formats[0];
>  	info->wsize = &info->devtype->win_sizes[0];
>
> @@ -2013,17 +1992,31 @@ static void ov7670_remove(struct i2c_client *client)
>  	media_entity_cleanup(&info->sd.entity);
>  }
>
> +static const struct ov7670_devtype ov7670_devdata = {
> +	.win_sizes = ov7670_win_sizes,
> +	.n_win_sizes = ARRAY_SIZE(ov7670_win_sizes),
> +	.set_framerate = ov7670_set_framerate_legacy,
> +	.get_framerate = ov7670_get_framerate_legacy,
> +};
> +
> +static const struct ov7670_devtype ov7675_devdata = {
> +	.win_sizes = ov7675_win_sizes,
> +	.n_win_sizes = ARRAY_SIZE(ov7675_win_sizes),
> +	.set_framerate = ov7675_set_framerate,
> +	.get_framerate = ov7675_get_framerate,
> +};
> +
>  static const struct i2c_device_id ov7670_id[] = {
> -	{ "ov7670", MODEL_OV7670 },
> -	{ "ov7675", MODEL_OV7675 },
> -	{ }
> +	{ "ov7670", (kernel_ulong_t)&ov7670_devdata },
> +	{ "ov7675", (kernel_ulong_t)&ov7675_devdata },
> +	{ /* sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(i2c, ov7670_id);
>
>  #if IS_ENABLED(CONFIG_OF)
>  static const struct of_device_id ov7670_of_match[] = {
> -	{ .compatible = "ovti,ov7670", },
> -	{ /* sentinel */ },
> +	{ .compatible = "ovti,ov7670", &ov7670_devdata },
> +	{ /* sentinel */ }

The patch looks good to me, would be nice to know if you have been
able to run-time test at least one of the drivers you have moved to
use i2c_get_match_data().

Reviewed-by: Jacopo Mondi <jacopo.mondi+renesas@...asonboard.com>

>  };
>  MODULE_DEVICE_TABLE(of, ov7670_of_match);
>  #endif
> --
> 2.25.1
>