linux-kernel - Re: [PATCH v6 2/2] leds: rt5033: Add RT5033 Flash led device driver

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Date:	Thu, 26 Nov 2015 10:43:25 +0100
From:	Jacek Anaszewski <j.anaszewski@...sung.com>
To:	Ingi Kim <ingi2.kim@...sung.com>
Cc:	robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	sameo@...ux.intel.com, lee.jones@...aro.org, rpurdie@...ys.net,
	inki.dae@...sung.com, sw0312.kim@...sung.com,
	beomho.seo@...sung.com, andi.shyti@...sung.com,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-leds@...r.kernel.org
Subject: Re: [PATCH v6 2/2] leds: rt5033: Add RT5033 Flash led device driver

Hi Ingi,

On 11/26/2015 09:02 AM, Ingi Kim wrote:
[...]
>>> +torch_unlock:
>>> +    mutex_unlock(&led->lock);
>>> +    return ret;
>>> +}
>>> +
>>> +static int rt5033_led_flash_brightness_set(struct led_classdev_flash *fled_cdev,
>>> +                       u32 brightness)
>>> +{
>>> +    struct rt5033_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
>>> +    struct rt5033_led *led = sub_led_to_led(sub_led);
>>> +
>>> +    mutex_lock(&led->lock);
>>> +    sub_led->flash_brightness = brightness;
>>> +    mutex_unlock(&led->lock);
>>
>> Mutex protection is redundant in this case. You would need it if device
>> state was also changed here.
>
> Okay, I'll remove it.
>
>>
>> BTW why flash brightness can't be written to the device here?
>>
>
> Flash brightness is only affected when FLED flashed (strobing).
> So, I think it is better to be written in rt5033_led_flash_strobe_set function.

strobe_set op should strobe the flash ASAP, and delegating brightness
setting there extends a delay between calling strobe_set op
and actual flash strobe. If you set the brightness here, then you
wouldn't have to do that in the strobe_set op, of course unless the
the brightness is altered through the API of the other LED, in two
separate LEDs case.

>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int rt5033_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
>>> +                    u32 timeout)
>>> +{
>>> +    struct rt5033_sub_led *sub_led = flcdev_to_sub_led(fled_cdev);
>>> +    struct rt5033_led *led = sub_led_to_led(sub_led);
>>> +
>>> +    mutex_lock(&led->lock);
>>> +    sub_led->flash_timeout = timeout;
>>> +    mutex_unlock(&led->lock);
>>
>> Ditto.
>>

Timeout should be also written here.

If you will add regmap_write in both ops, then mutex protection will
have to be preserved, to assure consistency between registers state
and sub_led->flash_brightness and sub_led->flash_timeout state.

>
>>> +#define RT5033_FLED_CTRL4_VTRREG_MAX    0x60
>>
>> Rename DEF to MASK.

Hmm, here it should be: Rename MAX to MASK.

-- 
Best Regards,
Jacek Anaszewski
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