Re: [PATCH v3 2/2] leds: add sgm3140 driver

[Luca Weiss]

On Montag, 27. April 2020 11:51:02 CEST Pavel Machek wrote:
> Hi!
> 
> > Add a driver for the SGMICRO SGM3140 Buck/Boost Charge Pump LED driver.
> > 
> > This device is controlled by two GPIO pins, one for enabling and the
> > second one for switching between torch and flash mode.
> > 
> > Signed-off-by: Luca Weiss <luca@xxxxxxxxx>
> 
> Thanks, applied, but... I may remove it again.
> 
> > +++ b/drivers/leds/leds-sgm3140.c
> > @@ -0,0 +1,320 @@
> > +// SPDX-License-Identifier: GPL-2.0
> 
> Would you consider GPL-2+?

I don't really have a preference either way but GPL-2.0-or-later is fine for 
me.

> 
> > +#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
> > +static void sgm3140_init_v4l2_flash_config(struct sgm3140 *priv,
> 
> Ok.
> 
> > +static int sgm3140_probe(struct platform_device *pdev)
> > +{
> 
> ...
> 
> > +	led_cdev->brightness_set_blocking = sgm3140_brightness_set;
> > +	led_cdev->max_brightness = LED_ON;
> 
> Don't do this, unless you really have 255 levels of brightness.

LED_ON is 1, so the brightness available is 0 - 1.

> 
> > +	/* Create V4L2 Flash subdev */
> > +	priv->v4l2_flash = v4l2_flash_init(&pdev->dev,
> > +					   child_node,
> > +					   fled_cdev, NULL,
> > +					   &v4l2_sd_cfg);
> > +	if (IS_ERR(priv->v4l2_flash)) {
> 
> Does this need some #ifdef guards?

v4l2_flash_init has a NULL-returning version when CONFIG_V4L2_FLASH_LED_CLASS 
is not defined (see https://elixir.bootlin.com/linux/latest/source/include/
media/v4l2-flash-led-class.h#L166 )

> 
> > +		ret = PTR_ERR(priv->v4l2_flash);
> > +		goto err;
> > +	}
> > +
> > +	return ret;
> 
> Should this return 0?

ret should be 0 here, so it shouldn't matter much.

> 
> > +err:
> > +	fwnode_handle_put(child_node);
> > +	return ret;
> > +}
> 
> Does non-error path needs handle_put, too?

I don't think so, I'm passing child_node to v4l2_flash_init which then saves 
the pointer to v4l2_subdev->fwnode. 

The devm_led_classdev_flash_register_ext function also seems to store the 
pointer (led_cdev->dev->fwnode = init_data->fwnode; in 
led_classdev_register_ext)

> 
> Best regards,
> 								
	Pavel

Regards,
Luca

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