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References: <20220927222152.132951-1-mike.rudenko@gmail.com>
 <20220927222152.132951-3-mike.rudenko@gmail.com>
 <15ebc256-1855-7720-05e1-6673b1da7d93@wanadoo.fr>
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From:   Mikhail Rudenko <mike.rudenko@gmail.com>
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc:     arec.kao@intel.com, c.hemp@phytec.de,
        dave.stevenson@raspberrypi.com, devicetree@vger.kernel.org,
        hverkuil@xs4all.nl, jimmy.su@intel.com,
        krzysztof.kozlowski+dt@linaro.org,
        laurent.pinchart+renesas@ideasonboard.com,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        marex@denx.de, mchehab@kernel.org, rdunlap@infradead.org,
        robh+dt@kernel.org, sakari.ailus@linux.intel.com,
        shawnx.tu@intel.com, tommaso.merciai@amarulasolutions.com
Subject: Re: [PATCH v3 2/2] media: i2c: add support for OV4689
Date:   Thu, 20 Oct 2022 03:22:59 +0300
In-reply-to: <15ebc256-1855-7720-05e1-6673b1da7d93@wanadoo.fr>
Message-ID: <87fsfjz67r.fsf@gmail.com>
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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 =C3=A0 00:21, Mikhail Rudenko a =C3=A9crit=C2=A0:
>> 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 =3D &ov4689->client->dev;
>> +	u32 id =3D 0;
>> +	int ret;
>> +
>> +	ret =3D ov4689_read_reg(client, OV4689_REG_CHIP_ID,
>> +			      OV4689_REG_VALUE_16BIT, &id);
>> +	if (id !=3D 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=3D=3D0 && id !=3D 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 =3D &client->dev;
>> +	struct v4l2_subdev *sd;
>> +	struct ov4689 *ov4689;
>> +	int ret;
>> +
>> +	ret =3D ov4689_check_hwcfg(dev);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ov4689 =3D devm_kzalloc(dev, sizeof(*ov4689), GFP_KERNEL);
>> +	if (!ov4689)
>> +		return -ENOMEM;
>> +
>> +	ov4689->client =3D client;
>> +	ov4689->cur_mode =3D &supported_modes[OV4689_MODE_2688_1520];
>> +
>> +	ov4689->xvclk =3D 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 =3D clk_get_rate(ov4689->xvclk);
>> +	}
>> +
>> +	if (ov4689->clock_rate !=3D 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 =3D 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 =3D devm_gpiod_get_optional(dev, "pwdn", GPIOD_OUT_L=
OW);
>> +	if (IS_ERR(ov4689->pwdn_gpio)) {
>> +		dev_err(dev, "Failed to get pwdn-gpios\n");
>> +		return PTR_ERR(ov4689->pwdn_gpio);
>> +	}
>> +
>> +	ret =3D 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 =3D &ov4689->subdev;
>> +	v4l2_i2c_subdev_init(sd, client, &ov4689_subdev_ops);
>> +	ret =3D ov4689_initialize_controls(ov4689);
>> +	if (ret)
>> +		goto err_destroy_mutex;
>> +
>> +	ret =3D ov4689_power_on(dev);
>> +	if (ret)
>> +		goto err_free_handler;
>> +
>> +	ret =3D ov4689_check_sensor_id(ov4689, client);
>> +	if (ret)
>> +		goto err_power_off;
>> +
>> +#ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
>> +	sd->internal_ops =3D &ov4689_internal_ops;
>> +	sd->flags |=3D V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +#endif
>> +#if defined(CONFIG_MEDIA_CONTROLLER)
>> +	ov4689->pad.flags =3D MEDIA_PAD_FL_SOURCE;
>> +	sd->entity.function =3D MEDIA_ENT_F_CAM_SENSOR;
>> +	ret =3D media_entity_pads_init(&sd->entity, 1, &ov4689->pad);
>> +	if (ret < 0)
>> +		goto err_power_off;
>> +#endif
>> +
>> +	ret =3D 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