linux-kernel - Re: [PATCH v2] leds: lm3532: Fix optional led-max-microamp prop error handling

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Date:   Thu, 12 Sep 2019 14:47:32 -0500
From:   Dan Murphy <dmurphy@...com>
To:     Jacek Anaszewski <jacek.anaszewski@...il.com>, <pavel@....cz>
CC:     <linux-leds@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] leds: lm3532: Fix optional led-max-microamp prop error
 handling

Jacek

On 9/12/19 2:12 PM, Jacek Anaszewski wrote:
> On 9/12/19 8:32 PM, Jacek Anaszewski wrote:> Hi Dan,
>> Thank you for the update.
>>
>> On 9/11/19 8:27 PM, Dan Murphy wrote:
>>> Fix the error handling for the led-max-microamp property.
>>> Need to check if the property is present and then if it is
>>> retrieve the setting and its max boundary
>>>
>>> Reported-by: Pavel Machek <pavel@....cz>
>>> Signed-off-by: Dan Murphy <dmurphy@...com>
>>> ---
>>>
>>> v2 - Changed full scale current check to use min function
>>>
>>>   drivers/leds/leds-lm3532.c | 14 +++++++++-----
>>>   1 file changed, 9 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/leds/leds-lm3532.c b/drivers/leds/leds-lm3532.c
>>> index 62ace6698d25..a1742dc1f6fa 100644
>>> --- a/drivers/leds/leds-lm3532.c
>>> +++ b/drivers/leds/leds-lm3532.c
>>> @@ -601,11 +601,15 @@ static int lm3532_parse_node(struct lm3532_data *priv)
>>>   			goto child_out;
>>>   		}
>>>   
>>> -		ret = fwnode_property_read_u32(child, "led-max-microamp",
>>> -					       &led->full_scale_current);
>>> -
>>> -		if (led->full_scale_current > LM3532_FS_CURR_MAX)
>>> -			led->full_scale_current = LM3532_FS_CURR_MAX;
>>> +		if (fwnode_property_present(child, "led-max-microamp")) {
>>> +			if (fwnode_property_read_u32(child, "led-max-microamp",
>>> +						     &led->full_scale_current))
>>> +				dev_err(&priv->client->dev,
>>> +					"Failed getting led-max-microamp\n");
>>> +			else
>>> +				min(led->full_scale_current,
>>> +				    LM3532_FS_CURR_MAX);
> I didn't previously notice lack of assignment of min() return value.
>
> I've amended that and while at it improved a bit this construction to
> avoid some indentations and line breaks:
>
> diff --git a/drivers/leds/leds-lm3532.c b/drivers/leds/leds-lm3532.c
> index 62ace6698d25..0507c6575c08 100644
> --- a/drivers/leds/leds-lm3532.c
> +++ b/drivers/leds/leds-lm3532.c
> @@ -601,11 +601,14 @@ static int lm3532_parse_node(struct lm3532_data *priv)
>                  goto child_out;
>          }
>
> -       ret = fwnode_property_read_u32(child, "led-max-microamp",
> -                                      &led->full_scale_current);
> -
> -       if (led->full_scale_current > LM3532_FS_CURR_MAX)
> -               led->full_scale_current = LM3532_FS_CURR_MAX;
> +       if (fwnode_property_present(child, "led-max-microamp") &&
> +           fwnode_property_read_u32(child, "led-max-microamp",
> +                                    &led->full_scale_current))
> +               dev_err(&priv->client->dev,
> +                       "Failed getting led-max-microamp\n");
> +       else
> +               led->full_scale_current = min(led->full_scale_current,
> +                                             LM3532_FS_CURR_MAX);
>
>          if (led->mode == LM3532_BL_MODE_ALS) {
>                  led->mode = LM3532_ALS_CTRL;
>
>
> Please let me know in case of any doubts.

This looks fine.  It always passed for me because I never set the FSC 
above max

Dan