linux-kernel - Re: [PATCH v4 04/11] leds: aw200xx: calculate dts property display

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Message-ID: <20231123163252.GF1354538@google.com>
Date:   Thu, 23 Nov 2023 16:32:52 +0000
From:   Lee Jones <lee@...nel.org>
To:     Dmitry Rokosov <ddrokosov@...utedevices.com>
Cc:     pavel@....cz, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        andy.shevchenko@...il.com, kernel@...rdevices.ru,
        rockosov@...il.com, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        George Stark <gnstark@...utedevices.com>
Subject: Re: [PATCH v4 04/11] leds: aw200xx: calculate dts property
 display_rows in the driver

On Tue, 21 Nov 2023, Dmitry Rokosov wrote:

> From: George Stark <gnstark@...utedevices.com>
> 
> Get rid of device tree property "awinic,display-rows". The property
> value actually means number of current switches and depends on how leds

Nit: LEDs

> are connected to the device. It should be calculated manually by max
> used led number. In the same way it is computed automatically now.

As above - I won't mention this again.

> Max used led is taken from led definition subnodes.
> 
> Signed-off-by: George Stark <gnstark@...utedevices.com>
> Signed-off-by: Dmitry Rokosov <ddrokosov@...utedevices.com>
> ---
>  drivers/leds/leds-aw200xx.c | 39 +++++++++++++++++++++++++------------
>  1 file changed, 27 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/leds/leds-aw200xx.c b/drivers/leds/leds-aw200xx.c
> index 7762b3a132ac..4bce5e7381c0 100644
> --- a/drivers/leds/leds-aw200xx.c
> +++ b/drivers/leds/leds-aw200xx.c
> @@ -379,6 +379,30 @@ static void aw200xx_disable(const struct aw200xx *const chip)
>  	return gpiod_set_value_cansleep(chip->hwen, 0);
>  }
>  
> +static bool aw200xx_probe_get_display_rows(struct device *dev, struct aw200xx *chip)
> +{
> +	struct fwnode_handle *child;
> +	u32 max_source = 0;
> +
> +	device_for_each_child_node(dev, child) {
> +		u32 source;
> +		int ret;
> +
> +		ret = fwnode_property_read_u32(child, "reg", &source);
> +		if (ret || source >= chip->cdef->channels)

Shouldn't the second clause fail instantly?

> +			continue;
> +
> +		max_source = max(max_source, source);
> +	}
> +
> +	if (!max_source)

Since max_source is an integer, please use an '== 0' comparison.

> +		return false;
> +
> +	chip->display_rows = max_source / chip->cdef->display_size_columns + 1;
> +
> +	return true;
> +}
> +
>  static int aw200xx_probe_fw(struct device *dev, struct aw200xx *chip)
>  {
>  	struct fwnode_handle *child;
> @@ -386,18 +410,9 @@ static int aw200xx_probe_fw(struct device *dev, struct aw200xx *chip)
>  	int ret;
>  	int i;
>  
> -	ret = device_property_read_u32(dev, "awinic,display-rows",
> -				       &chip->display_rows);
> -	if (ret)
> -		return dev_err_probe(dev, ret,
> -				     "Failed to read 'display-rows' property\n");
> -
> -	if (!chip->display_rows ||
> -	    chip->display_rows > chip->cdef->display_size_rows_max) {
> -		return dev_err_probe(dev, ret,
> -				     "Invalid leds display size %u\n",
> -				     chip->display_rows);
> -	}
> +	if (!aw200xx_probe_get_display_rows(dev, chip))

Function calls in side if() statements in general is rough.

Please break it out and use 'ret' as we usually do.

> +		return dev_err_probe(dev, -EINVAL,

Make this the return value from aw200xx_probe_get_display_rows() and use
'ret' instead.

> +				     "No valid led definitions found\n");
>  
>  	current_max = aw200xx_imax_from_global(chip, AW200XX_IMAX_MAX_uA);
>  	current_min = aw200xx_imax_from_global(chip, AW200XX_IMAX_MIN_uA);
> -- 
> 2.36.0
> 

-- 
Lee Jones [李琼斯]