Re: [PATCH v8 5/5] backlight: add led-backlight driver

[Jean-Jacques Hiblot]

Sebastian,

On 03/10/2019 13:47, Sebastian Reichel wrote:
> Hi,
>
> On Thu, Oct 03, 2019 at 10:28:12AM +0200, Jean-Jacques Hiblot wrote:
> > From: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> >
> > This patch adds a led-backlight driver (led_bl), which is similar to
> > pwm_bl except the driver uses a LED class driver to adjust the
> > brightness in the HW. Multiple LEDs can be used for a single backlight.
> >
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxx>
> > Acked-by: Pavel Machek <pavel@xxxxxx>
> > Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> > ---
> Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
>
> (with some suggestions below)

[...]


> I suggest to restructure:
>
> 1. call led_sysfs_disable
>
> 2. use devm_add_action_or_reset() to register the
>     led_sysfs_enable loop
>
> 3. use devm_backlight_device_register() to register BL
>
> 4. drop the remove function
>
> > +
> > +	backlight_update_status(priv->bl_dev);
> > +
> > +	return 0;
> > +}
> > +
> > +static int led_bl_remove(struct platform_device *pdev)
> > +{
> > +	struct led_bl_data *priv = platform_get_drvdata(pdev);
> > +	struct backlight_device *bl = priv->bl_dev;
> > +	int i;
> > +
> > +	backlight_device_unregister(bl);
> > +
> > +	led_bl_power_off(priv);
> > +	for (i = 0; i < priv->nb_leds; i++)
> > +		led_sysfs_enable(priv->leds[i]);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id led_bl_of_match[] = {
> > +	{ .compatible = "led-backlight" },
> > +	{ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, led_bl_of_match);
> > +
> > +static struct platform_driver led_bl_driver = {
> > +	.driver		= {
> > +		.name		= "led-backlight",
> > +		.of_match_table	= of_match_ptr(led_bl_of_match),
> You should drop of_match_ptr(). Since the driver depends on OF,
> it will always simply return led_bl_of_match.
>
> (Also after removing the OF dependency from the driver it would
> either require led_bl_of_match to be marked __maybe_unused or
> moving it into a #if CONFIG_OF area to avoid warnings.)

Thanks for the suggestions. I think I'll work on them as a separate 
thing and post them after this is merged if there are no others changes 
required.

JJ

> -- Sebastian
>
> > +	},
> > +	.probe		= led_bl_probe,
> > +	.remove		= led_bl_remove,
> > +};
> > +
> > +module_platform_driver(led_bl_driver);
> > +
> > +MODULE_DESCRIPTION("LED based Backlight Driver");
> > +MODULE_LICENSE("GPL");
> > +MODULE_ALIAS("platform:led-backlight");
> > --
> > 2.17.1
> >
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