Re: [V2, 2/2] media: i2c: Add more sensor modes for ov8856 camera sensor

[Dongchun Zhu <dongchun.zhu@mediatek.com>]

Hi Andy,

On Tue, 2019-09-10 at 20:44 +0300, Andy Shevchenko wrote:
> On Tue, Sep 10, 2019 at 09:04:46PM +0800, dongchun.zhu@mediatek.com wrote:
> > From: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > 
> > This patch mainly adds two more sensor modes for OV8856 CMOS image sensor.
> > That is, the resolution of 1632*1224 and 3264*2448, corresponding to the bayer order of BGGR.
> > The sensor revision also differs in some OTP register.
> 
> > +static int __ov8856_power_on(struct ov8856 *ov8856)
> > +{
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> > +	int ret;
> > +
> > +	ret = clk_prepare_enable(ov8856->xvclk);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev, "failed to enable xvclk\n");
> > +		return ret;
> > +	}
> > +
> > +	gpiod_set_value_cansleep(ov8856->n_shutdn_gpio, GPIOD_OUT_LOW);
> > +
> > +	ret = regulator_bulk_enable(OV8856_NUM_SUPPLIES, ov8856->supplies);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev, "failed to enable regulators\n");
> > +		goto disable_clk;
> > +	}
> > +
> > +	gpiod_set_value_cansleep(ov8856->n_shutdn_gpio, GPIOD_OUT_HIGH);
> > +
> 
> > +	usleep_range(1400, 1500);
> 
> This should be commented why this is needed and from where the requirement
> comes from. Also, not, that 100us, which is only ~7%, is small margin.
> Recommended one is ~20%.
> 

Thanks for reminder.
This would be refined in next release.

> > +
> > +	return 0;
> > +
> > +disable_clk:
> > +	clk_disable_unprepare(ov8856->xvclk);
> > +
> > +	return ret;
> > +}
> 
> > +	ov8856->is_1B_revision = (val == OV8856_1B_MODULE) ? 1 : 0;
> 
> !! will give same result without using ternary operator.
> 

Fixed in next release.

> > +	ov8856->xvclk = devm_clk_get(&client->dev, "xvclk");
> > +	if (IS_ERR(ov8856->xvclk)) {
> > +		dev_err(&client->dev, "failed to get xvclk\n");
> > +		return -EINVAL;
> > +	}
> 
> Previously it was optional.
> How did it work before and why it's not optional?
> 

Previous vision for this driver is for ACPI, not ARM.

> > +	ov8856->n_shutdn_gpio = devm_gpiod_get(&client->dev, "reset",
> > +					       GPIOD_OUT_LOW);
> > +	if (IS_ERR(ov8856->n_shutdn_gpio)) {
> > +		dev_err(&client->dev, "failed to get reset-gpios\n");
> > +		return -EINVAL;
> > +	}
> 
> Ditto.
> 
> > +static const struct of_device_id ov8856_of_match[] = {
> > +	{ .compatible = "ovti,ov8856" },
> 
> > +	{},
> 
> No comma needed for terminator line.
> 

Fixed in next release.

> > +};
>