[PATCH 3/5] media: ov2640: add primary dt support

[Laurent Pinchart]

Hi Josh,

Thank you for the patch.

On Monday 08 December 2014 19:29:05 Josh Wu wrote:
> Add device tree support for ov2640.
> 
> Cc: devicetree at vger.kernel.org
> Signed-off-by: Josh Wu <josh.wu at atmel.com>
> ---
> v1 -> v2:
>   1. use gpiod APIs.
>   2. change the gpio pin's name according to datasheet.
>   3. reduce the delay for .reset() function.
> 
>  drivers/media/i2c/soc_camera/ov2640.c | 86 +++++++++++++++++++++++++++++---
>  1 file changed, 80 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/i2c/soc_camera/ov2640.c
> b/drivers/media/i2c/soc_camera/ov2640.c index 9ee910d..2a57979 100644
> --- a/drivers/media/i2c/soc_camera/ov2640.c
> +++ b/drivers/media/i2c/soc_camera/ov2640.c
> @@ -18,6 +18,8 @@
>  #include <linux/i2c.h>
>  #include <linux/slab.h>
>  #include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/of_gpio.h>
>  #include <linux/v4l2-mediabus.h>
>  #include <linux/videodev2.h>
> 
> @@ -283,6 +285,10 @@ struct ov2640_priv {
>  	u32	cfmt_code;
>  	struct v4l2_clk			*clk;
>  	const struct ov2640_win_size	*win;
> +
> +	struct soc_camera_subdev_desc	ssdd_dt;
> +	struct gpio_desc *resetb_gpio;
> +	struct gpio_desc *pwdn_gpio;
>  };
> 
>  /*
> @@ -1047,6 +1053,61 @@ static struct v4l2_subdev_ops ov2640_subdev_ops = {
>  	.video	= &ov2640_subdev_video_ops,
>  };
> 
> +/* OF probe functions */
> +static int ov2640_hw_power(struct device *dev, int on)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct ov2640_priv *priv = to_ov2640(client);
> +
> +	dev_dbg(&client->dev, "%s: %s the camera\n",
> +			__func__, on ? "ENABLE" : "DISABLE");
> +
> +	if (priv->pwdn_gpio && !IS_ERR(priv->pwdn_gpio))

No need to test for IS_ERR, as the probe function would have failed in that 
case.

> +		gpiod_direction_output(priv->pwdn_gpio, !on);
> +
> +	return 0;
> +}
> +
> +static int ov2640_hw_reset(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct ov2640_priv *priv = to_ov2640(client);
> +
> +	/* If enabled, give a reset impulse */
> +	if (priv->resetb_gpio && !IS_ERR(priv->resetb_gpio)) {

Same here.

> +		gpiod_direction_output(priv->resetb_gpio, 0);

Given that your DT should specify the active low GPIO flag, and that the gpiod 
API inverts the value in that case, you should set the value to 1 here.

> +		usleep_range(3000, 5000);
> +		gpiod_direction_output(priv->resetb_gpio, 1);

And to 0 here.

> +	}
> +
> +	return 0;
> +}
> +
> +static int ov2640_probe_dt(struct i2c_client *client,
> +		struct ov2640_priv *priv)
> +{
> +	priv->resetb_gpio = devm_gpiod_get_optional(&client->dev, "resetb",
> +			GPIOD_OUT_HIGH);
> +	if (!priv->resetb_gpio)
> +		dev_warn(&client->dev, "resetb gpio not found!\n");

No need to warn here, it's perfectly fine if the reset signal isn't connected 
to a GPIO.

> +	else if (IS_ERR(priv->resetb_gpio))
> +		return -EINVAL;
> +
> +	priv->pwdn_gpio = devm_gpiod_get_optional(&client->dev, "pwdn",
> +			GPIOD_OUT_HIGH);
> +	if (!priv->pwdn_gpio)
> +		dev_warn(&client->dev, "pwdn gpio not found!\n");

Same here.

> +	else if (IS_ERR(priv->pwdn_gpio))
> +		return -EINVAL;
> +
> +	/* Initialize the soc_camera_subdev_desc */
> +	priv->ssdd_dt.power = ov2640_hw_power;
> +	priv->ssdd_dt.reset = ov2640_hw_reset;
> +	client->dev.platform_data = &priv->ssdd_dt;
> +
> +	return 0;
> +}
> +
>  /*
>   * i2c_driver functions
>   */
> @@ -1058,12 +1119,6 @@ static int ov2640_probe(struct i2c_client *client,
>  	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
>  	int			ret;
> 
> -	if (!ssdd) {
> -		dev_err(&adapter->dev,
> -			"OV2640: Missing platform_data for driver\n");
> -		return -EINVAL;
> -	}
> -
>  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
>  		dev_err(&adapter->dev,
>  			"OV2640: I2C-Adapter doesn't support SMBUS\n");
> @@ -1077,6 +1132,18 @@ static int ov2640_probe(struct i2c_client *client,
>  		return -ENOMEM;
>  	}
> 
> +	if (!ssdd) {
> +		if (client->dev.of_node) {
> +			ret = ov2640_probe_dt(client, priv);
> +			if (ret)
> +				return ret;
> +		} else {
> +			dev_err(&client->dev,
> +				"Missing platform_data for driver\n");
> +			return  -EINVAL;
> +		}

I would test for !client->dev.of_node and return the error, you could then get 
rid of the else and lower the indentation level for the call to 
ov2640_probe_dt().

> +	}
> +
>  	v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops);
>  	v4l2_ctrl_handler_init(&priv->hdl, 2);
>  	v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,
> @@ -1123,9 +1190,16 @@ static const struct i2c_device_id ov2640_id[] = {
>  };
>  MODULE_DEVICE_TABLE(i2c, ov2640_id);
> 
> +static const struct of_device_id ov2640_of_match[] = {
> +	{.compatible = "ovti,ov2640", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, ov2640_of_match);
> +
>  static struct i2c_driver ov2640_i2c_driver = {
>  	.driver = {
>  		.name = "ov2640",
> +		.of_match_table = of_match_ptr(ov2640_of_match),
>  	},
>  	.probe    = ov2640_probe,
>  	.remove   = ov2640_remove,

-- 
Regards,

Laurent Pinchart