linux-kernel - Re: [PATCH v4 2/2] Add support for OV5647 sensor

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Date:   Tue, 15 Nov 2016 13:10:32 +0100
From:   Pavel Machek <pavel@....cz>
To:     Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>
Cc:     mchehab@...nel.org, linux-kernel@...r.kernel.org,
        linux-media@...r.kernel.org, robh+dt@...nel.org,
        devicetree@...r.kernel.org, davem@...emloft.net,
        gregkh@...uxfoundation.org, geert+renesas@...der.be,
        akpm@...ux-foundation.org, linux@...ck-us.net, hverkuil@...all.nl,
        dheitmueller@...nellabs.com, slongerbeam@...il.com,
        lars@...afoo.de, robert.jarzmik@...e.fr, pali.rohar@...il.com,
        sakari.ailus@...ux.intel.com, mark.rutland@....com,
        CARLOS.PALMINHA@...opsys.com
Subject: Re: [PATCH v4 2/2] Add support for OV5647 sensor

Hi!

> Add support for OV5647 sensor.
> 

> +static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
> +{
> +	int ret;
> +	unsigned char data[3] = { reg >> 8, reg & 0xff, val};
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = i2c_master_send(client, data, 3);
> +	if (ret != 3) {
> +		dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
> +				__func__, reg);
> +		return ret < 0 ? ret : -EIO;
> +	}
> +	return 0;
> +}

Sorry, this is wrong. It should something <0 any time error is detected.

> +static int ov5647_write_array(struct v4l2_subdev *sd,
> +				struct regval_list *regs, int array_size)
> +{
> +	int i = 0;
> +	int ret = 0;
> +
> +	if (!regs)
> +		return -EINVAL;
> +
> +	while (i < array_size) {
> +		ret = ov5647_write(sd, regs->addr, regs->data);
> +		if (ret < 0)
> +			return ret;
> +		i++;
> +		regs++;
> +	}
> +	return 0;
> +}

For example this expects <0 on error.

> +static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
> +{
> +	int ret;
> +	unsigned char rdval;
> +
> +	ret = ov5647_read(sd, 0x0100, &rdval);
> +	if (ret != 0)
> +		return ret;
> +
> +	if (standby)
> +		ret = ov5647_write(sd, 0x0100, rdval&0xfe);
> +	else
> +		ret = ov5647_write(sd, 0x0100, rdval|0x01);
> +
> +	return ret;

if (standby)
     rdval &= 0xfe;
else
     rdval |= 0x01;

ret = ov5647_write(sd, 0x0100, rdval);

?


> +/**
> + * @short Store information about the video data format.
> + */
> +static struct sensor_format_struct {
> +	__u8 *desc;
> +	u32 mbus_code;

u8 is suitable here.


> +	ov5647_read(sd, 0x0100, &resetval);
> +		if (!resetval&0x01) {

add ()s here.

> +static int sensor_power(struct v4l2_subdev *sd, int on)
> +{
> +	int ret;
> +	struct ov5647 *ov5647 = to_state(sd);
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +
> +	ret = 0;
> +	mutex_lock(&ov5647->lock);
> +
> +	if (on)	{
> +		dev_dbg(&client->dev, "OV5647 power on!\n");
> +
> +		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
> +				ARRAY_SIZE(sensor_oe_enable_regs));
> +
> +		ret = __sensor_init(sd);
> +
> +		if (ret < 0)
> +			dev_err(&client->dev,
> +				"Camera not available! Check Power!\n");
> +	} else {
> +		dev_dbg(&client->dev, "OV5647 power off!\n");
> +
> +		dev_dbg(&client->dev, "disable oe\n");
> +		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
> +				ARRAY_SIZE(sensor_oe_disable_regs));
> +
> +		if (ret < 0)
> +			dev_dbg(&client->dev, "disable oe failed!\n");
> +
> +		ret = set_sw_standby(sd, true);
> +
> +		if (ret < 0)
> +			dev_dbg(&client->dev, "soft stby failed!\n");

dev_err for errors? Little less "!"s in the output?

> +static int sensor_get_register(struct v4l2_subdev *sd,
> +				struct v4l2_dbg_register *reg)
> +{
> +	unsigned char val = 0;
> +	int ret;
> +
> +	ret = ov5647_read(sd, reg->reg & 0xff, &val);
> +	reg->val = val;
> +	reg->size = 1;
> +	return ret;
> +}

Filling reg->* when read failed is strange.

> +static int sensor_set_register(struct v4l2_subdev *sd,
> +				const struct v4l2_dbg_register *reg)
> +{
> +	ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
> +	return 0;
> +}

error handling?

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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