Re: [PATCH v2 2/2] media: Add a driver for the ov5645 camera sensor.

[Stanimir Varbanov <stanimir.varbanov@linaro.org>]

Hi Todor,

Thanks for the patch, few comments below.

On 05/18/2016 02:50 PM, Todor Tomov wrote:
> The ov5645 sensor from Omnivision supports up to 2592x1944
> and CSI2 interface.
> 
> The driver adds support for the following modes:
> - 1280x960
> - 1920x1080
> - 2592x1944
> 
> Output format is packed 8bit UYVY.
> 
> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
> ---
>  drivers/media/i2c/Kconfig  |   11 +
>  drivers/media/i2c/Makefile |    1 +
>  drivers/media/i2c/ov5645.c | 1425 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1437 insertions(+)
>  create mode 100644 drivers/media/i2c/ov5645.c
> 
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 521bbf1..aa17eba 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -490,6 +490,17 @@ config VIDEO_OV2659
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ov2659.
>  
> +config VIDEO_OV5645
> +	tristate "OmniVision OV5645 sensor support"
> +	depends on I2C && VIDEO_V4L2
> +	depends on MEDIA_CAMERA_SUPPORT

depends on OF ?

<cut>

> +
> +struct ov5645 {
> +	struct i2c_client *i2c_client;
> +	struct device *dev;
> +	struct v4l2_subdev sd;
> +	struct media_pad pad;
> +	struct v4l2_of_endpoint ep;
> +	struct v4l2_mbus_framefmt fmt;
> +	struct v4l2_rect crop;
> +	struct clk *xclk;
> +	u32 xclk_freq;

this become unused?

> +
> +	struct regulator *io_regulator;
> +	struct regulator *core_regulator;
> +	struct regulator *analog_regulator;
> +
> +	enum ov5645_mode current_mode;
> +
> +	/* Cached control values */
> +	struct v4l2_ctrl_handler ctrls;
> +	struct v4l2_ctrl *saturation;
> +	struct v4l2_ctrl *hflip;
> +	struct v4l2_ctrl *vflip;
> +	struct v4l2_ctrl *autogain;
> +	struct v4l2_ctrl *autoexposure;
> +	struct v4l2_ctrl *awb;
> +	struct v4l2_ctrl *pattern;
> +
> +	struct mutex power_lock; /* lock to protect power state */
> +	int power;
> +
> +	struct gpio_desc *pwdn_gpio;
> +	struct gpio_desc *rst_gpio;
> +};
> +
> +static inline struct ov5645 *to_ov5645(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct ov5645, sd);
> +}

<cut>

> +static int ov5645_s_power(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov5645 *ov5645 = to_ov5645(sd);
> +	int ret = 0;
> +
> +	dev_dbg(ov5645->dev, "%s: on = %d\n", __func__, on);
> +
> +	mutex_lock(&ov5645->power_lock);
> +
> +	/* If the power count is modified from 0 to != 0 or from != 0 to 0,
> +	 * update the power state.
> +	 */
> +	if (ov5645->power == !on) {
> +		if (on) {
> +			ret = ov5645_set_power_on(ov5645);
> +			if (ret < 0) {
> +				dev_err(ov5645->dev, "could not set power %s\n",
> +					on ? "on" : "off");
> +				goto exit;
> +			}
> +
> +			ret = ov5645_init(ov5645);
> +			if (ret < 0) {
> +				dev_err(ov5645->dev,
> +					"could not set init registers\n");
> +				goto exit;
> +			}
> +
> +			ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> +					 OV5645_SYSTEM_CTRL0_STOP);

please check the error code.

> +		} else {
> +			ov5645_set_power_off(ov5645);
> +		}
> +
> +		/* Update the power count. */
> +		ov5645->power += on ? 1 : -1;
> +		WARN_ON(ov5645->power < 0);
> +	}
> +
> +exit:
> +	mutex_unlock(&ov5645->power_lock);
> +
> +	return ret;
> +}
> +

<cut>

> +
> +static int ov5645_registered(struct v4l2_subdev *subdev)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(subdev);
> +	struct ov5645 *ov5645 = to_ov5645(subdev);
> +	u8 chip_id_high, chip_id_low;
> +	int ret;
> +
> +	ov5645_s_power(&ov5645->sd, true);

check for error here and on the other places where call s_power.

> +
> +	ret = ov5645_read_reg(ov5645, OV5645_CHIP_ID_HIGH_REG, &chip_id_high);
> +	if (ret < 0 || chip_id_high != OV5645_CHIP_ID_HIGH) {
> +		dev_err(ov5645->dev, "could not read ID high\n");
> +		ret = -ENODEV;
> +		goto reg_power_off;
> +	}
> +	ret = ov5645_read_reg(ov5645, OV5645_CHIP_ID_LOW_REG, &chip_id_low);
> +	if (ret < 0 || chip_id_low != OV5645_CHIP_ID_LOW) {
> +		dev_err(ov5645->dev, "could not read ID low\n");
> +		ret = -ENODEV;
> +		goto reg_power_off;
> +	}
> +
> +	dev_info(&client->dev, "OV5645 detected at address 0x%02x\n",
> +		 client->addr);
> +
> +	ov5645_s_power(&ov5645->sd, false);
> +
> +	return 0;
> +
> +reg_power_off:
> +	ov5645_s_power(&ov5645->sd, false);
> +	return ret;
> +}
> +
> +static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> +{
> +	struct ov5645 *ov5645 = to_ov5645(subdev);
> +	int ret;
> +
> +	dev_dbg(ov5645->dev, "%s: enable = %d\n", __func__, enable);
> +
> +	if (enable) {
> +		ret = ov5645_change_mode(ov5645, ov5645->current_mode);
> +		if (ret < 0) {
> +			dev_err(ov5645->dev, "could not set mode %d\n",
> +				ov5645->current_mode);
> +			return ret;
> +		}
> +		ret = v4l2_ctrl_handler_setup(&ov5645->ctrls);
> +		if (ret < 0) {
> +			dev_err(ov5645->dev, "could not sync v4l2 controls\n");
> +			return ret;
> +		}
> +		ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> +				 OV5645_SYSTEM_CTRL0_START);

Error code check here and below.

> +	} else {
> +		ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> +				 OV5645_SYSTEM_CTRL0_STOP);
> +	}
> +
> +	return 0;
> +}

<cut>

> +static int ov5645_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct device_node *endpoint;
> +	struct ov5645 *ov5645;
> +	int ret = 0;

no need to initialize

<cut>

> +
> +	ov5645->io_regulator = devm_regulator_get(dev, "dovdd");
> +	if (IS_ERR(ov5645->io_regulator)) {
> +		switch(PTR_ERR(ov5645->io_regulator)) {
> +		case -ENODEV:
> +			/* Regulator is optional so this is ok - continue */

if the regulator is optional then use devm_regulator_get_optional, thus
you can avoid checking ov5645->io_regulator for NULL.

and the error handling will be simply

if (IS_ERR(ret_reg))
	return PTR_ERR(ret_reg);

<cut>

> +
> +	ov5645->pwdn_gpio = devm_gpiod_get(dev, "pwdn", GPIOD_OUT_LOW);
> +	if (IS_ERR(ov5645->pwdn_gpio)) {
> +		switch(PTR_ERR(ov5645->pwdn_gpio)) {
> +		case -ENOENT:
> +			/* GPIO is optional so this is ok - continue */

you can use devm_gpiod_get_optional then.

> +			ov5645->pwdn_gpio = NULL;
> +			dev_dbg(dev, "power down gpio not present\n");
> +			break;
> +		case -EPROBE_DEFER:
> +			dev_dbg(dev, "power down gpio probe defered\n");
> +			return -EPROBE_DEFER;
> +		default:
> +			dev_err(dev, "cannot get power down gpio\n");
> +			return PTR_ERR(ov5645->pwdn_gpio);
> +		}
> +	}


-- 
regards,
Stan