Re: [PATCH v3 2/2] media: i2c: add support for OV4689

[Mikhail Rudenko <mike.rudenko@gmail.com>]

Hi Christophe,

Thanks for the review! See my comments below.

On 2022-10-18 at 20:55 +02, Christophe JAILLET <christophe.jaillet@wanadoo.fr> wrote:

> Le 28/09/2022 à 00:21, Mikhail Rudenko a écrit :
>> Add a V4L2 sub-device driver for OmniVision OV4689 image sensor. This
>> is a 4 Mpx image sensor using the I2C bus for control and the CSI-2
>> bus for data.
>> This driver supports following features:
>> - manual exposure and analog gain control support
>> - test pattern support
>> - media controller support
>> - runtime PM support
>> - support following resolutions:
>>    + 2688x1520 at 30 fps
>> The driver provides all mandatory V4L2 controls for compatibility
>> with
>> libcamera. The sensor supports 1/2/4-lane CSI-2 modes, but the driver
>> implements 4 lane mode only at this moment.
>
> Hi,
>
> a few nitpick below.
>
> CJ
>
>> Signed-off-by: Mikhail Rudenko
>> <mike.rudenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
>
> [...]
>
>> +static int ov4689_check_sensor_id(struct ov4689 *ov4689,
>> +				  struct i2c_client *client)
>> +{
>> +	struct device *dev = &ov4689->client->dev;
>> +	u32 id = 0;
>> +	int ret;
>> +
>> +	ret = ov4689_read_reg(client, OV4689_REG_CHIP_ID,
>> +			      OV4689_REG_VALUE_16BIT, &id);
>> +	if (id != CHIP_ID) {
>> +		dev_err(dev, "Unexpected sensor id(%06x), ret(%d)\n", id, ret);
>> +		return -ENODEV;
>
> return ret?
> (otherwise what is the point of -EINVAL and -EIO in ov4689_read_reg()?)
>

Maybe we should reserve -ENODEV for the case when
ret==0 && id != CHIP_ID and return ret otherwise?
What do you think about it?

>> +	}
>> +
>> +	dev_info(dev, "Detected OV%06x sensor\n", CHIP_ID);
>> +
>> +	return 0;
>> +}
>
> [...]
>
>> +static int ov4689_probe(struct i2c_client *client)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct v4l2_subdev *sd;
>> +	struct ov4689 *ov4689;
>> +	int ret;
>> +
>> +	ret = ov4689_check_hwcfg(dev);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ov4689 = devm_kzalloc(dev, sizeof(*ov4689), GFP_KERNEL);
>> +	if (!ov4689)
>> +		return -ENOMEM;
>> +
>> +	ov4689->client = client;
>> +	ov4689->cur_mode = &supported_modes[OV4689_MODE_2688_1520];
>> +
>> +	ov4689->xvclk = devm_clk_get_optional(dev, NULL);
>> +	if (IS_ERR(ov4689->xvclk)) {
>> +		return dev_err_probe(dev, PTR_ERR(ov4689->xvclk),
>> +				     "Failed to get external clock\n");
>> +	}
>> +
>> +	if (!ov4689->xvclk) {
>> +		dev_dbg(dev,
>> +			"No clock provided, using clock-frequency property\n");
>> +		device_property_read_u32(dev, "clock-frequency", &ov4689->clock_rate);
>> +	} else {
>> +		ov4689->clock_rate = clk_get_rate(ov4689->xvclk);
>> +	}
>> +
>> +	if (ov4689->clock_rate != OV4689_XVCLK_FREQ) {
>> +		dev_err(dev,
>> +			"External clock rate mismatch: got %d Hz, expected %d Hz\n",
>> +			ov4689->clock_rate, OV4689_XVCLK_FREQ);
>> +		return -EINVAL;
>> +	}
>> +
>> +	ov4689->reset_gpio = devm_gpiod_get_optional(dev, "reset",
>> +						     GPIOD_OUT_LOW);
>> +	if (IS_ERR(ov4689->reset_gpio)) {
>> +		dev_err(dev, "Failed to get reset-gpios\n");
>> +		return PTR_ERR(ov4689->reset_gpio);
>> +	}
>> +
>> +	ov4689->pwdn_gpio = devm_gpiod_get_optional(dev, "pwdn", GPIOD_OUT_LOW);
>> +	if (IS_ERR(ov4689->pwdn_gpio)) {
>> +		dev_err(dev, "Failed to get pwdn-gpios\n");
>> +		return PTR_ERR(ov4689->pwdn_gpio);
>> +	}
>> +
>> +	ret = ov4689_configure_regulators(ov4689);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to get power regulators\n");
>
> dev_err_probe()?
> I think that devm_regulator_bulk_get() can return -EPROBE_DEFER)
>

Nice catch, will fix in v4.

>> +		return ret;
>> +	}
>> +
>> +	mutex_init(&ov4689->mutex);
>> +
>> +	sd = &ov4689->subdev;
>> +	v4l2_i2c_subdev_init(sd, client, &ov4689_subdev_ops);
>> +	ret = ov4689_initialize_controls(ov4689);
>> +	if (ret)
>> +		goto err_destroy_mutex;
>> +
>> +	ret = ov4689_power_on(dev);
>> +	if (ret)
>> +		goto err_free_handler;
>> +
>> +	ret = ov4689_check_sensor_id(ov4689, client);
>> +	if (ret)
>> +		goto err_power_off;
>> +
>> +#ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
>> +	sd->internal_ops = &ov4689_internal_ops;
>> +	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +#endif
>> +#if defined(CONFIG_MEDIA_CONTROLLER)
>> +	ov4689->pad.flags = MEDIA_PAD_FL_SOURCE;
>> +	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
>> +	ret = media_entity_pads_init(&sd->entity, 1, &ov4689->pad);
>> +	if (ret < 0)
>> +		goto err_power_off;
>> +#endif
>> +
>> +	ret = v4l2_async_register_subdev_sensor(sd);
>> +	if (ret) {
>> +		dev_err(dev, "v4l2 async register subdev failed\n");
>> +		goto err_clean_entity;
>> +	}
>> +
>> +	pm_runtime_set_active(dev);
>> +	pm_runtime_enable(dev);
>> +	pm_runtime_idle(dev);
>> +
>> +	return 0;
>> +
>> +err_clean_entity:
>> +	media_entity_cleanup(&sd->entity);
>> +err_power_off:
>> +	ov4689_power_off(dev);
>> +err_free_handler:
>> +	v4l2_ctrl_handler_free(&ov4689->ctrl_handler);
>> +err_destroy_mutex:
>> +	mutex_destroy(&ov4689->mutex);
>> +
>> +	return ret;
>> +}
>
> [...]


--
Best regards,
Mikhail Rudenko