Re: [PATCH v2 5/8] leds: pca995x: Make output gain configurable

[Lee Jones <lee@kernel.org>]

On Tue, 15 Sep 2026, Nora Schiffer wrote:

> The output gain linearly configures the LED current in 255 levels; the
> absolute current depends on both the gain value and the R_ext resistor
> connected to the LED driver. Make the gain configurable in the Device
> Tree instead of hardcoding it to 128, allowing to adjust the current
> for different hardware designs.
> 
> Signed-off-by: Nora Schiffer <nora.schiffer@ew.tq-group.com>
> ---
> 
> v2: Add nxp, vendor prefix
> 
>  drivers/leds/leds-pca995x.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/leds/leds-pca995x.c b/drivers/leds/leds-pca995x.c
> index 0c0ea57f3225a..9cd5702573b0d 100644
> --- a/drivers/leds/leds-pca995x.c
> +++ b/drivers/leds/leds-pca995x.c
> @@ -127,6 +127,7 @@ static int pca995x_probe(struct i2c_client *client)
>  	struct pca995x_chip *chip;
>  	struct pca995x_led *led;
>  	int i, j, reg, ret;
> +	u32 iref;
>  
>  	chipdef = device_get_match_data(&client->dev);
>  
> @@ -154,6 +155,11 @@ static int pca995x_probe(struct i2c_client *client)
>  
>  	i2c_set_clientdata(client, chip);
>  
> +	if (device_property_read_u32(dev, "nxp,output-gain", &iref))
> +		iref = PCA995X_IREFALL_HALF_CFG;
> +	else if (iref > PCA995X_IREFALL_FULL_CFG)
> +		return dev_err_probe(dev, -EINVAL, "invalid nxp,output-gain\n");

As clever as is this, it's not that easy to follow.

I'd prefer:

	u32 iref = PCA995X_IREFALL_HALF_CFG;

	ret = device_property_read_u32(...);
	if (!ret) {
		if (val > PCA995X_IREFALL_FULL_CFG)
			 return dev_err_probe(dev, -EINVAL, "output-gain is out of range\n");
		iref = val;
	}

>  	device_for_each_child_node_scoped(dev, child) {
>  		ret = fwnode_property_read_u32(child, "reg", &reg);
>  		if (ret)
> @@ -196,7 +202,7 @@ static int pca995x_probe(struct i2c_client *client)
>  		return ret;
>  
>  	/* IREF Output current value for all LEDn outputs */
> -	return regmap_write(chip->regmap, chipdef->irefall, PCA995X_IREFALL_HALF_CFG);
> +	return regmap_write(chip->regmap, chipdef->irefall, iref);
>  }
>  
>  static const struct i2c_device_id pca995x_id[] = {
> -- 
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-- 
Lee Jones