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From: Jacek Anaszewski <jacek.anaszewski@gmail.com>
To: Pavel Machek <pavel@ucw.cz>, Gene Chen <gene.chen.richtek@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	cy_huang@richtek.com, linux-kernel@vger.kernel.org,
	Gene Chen <gene_chen@richtek.com>,
	benjamin.chao@mediatek.com, robh+dt@kernel.org,
	linux-mediatek@lists.infradead.org, Dan Murphy <dmurphy@ti.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Wilma.Wu@mediatek.com, linux-leds@vger.kernel.org,
	shufan_lee@richtek.com
Subject: Re: [PATCH v3 1/2] leds: mt6360: Add LED driver for MT6360
Date: Thu, 10 Sep 2020 22:23:18 +0200	[thread overview]
Message-ID: <489fc92f-f6f5-839e-e417-7761d404e6ae@gmail.com> (raw)
In-Reply-To: <20200910122958.GF7907@duo.ucw.cz>

On 9/10/20 2:29 PM, Pavel Machek wrote:
> Hi!
> 
>>>> +{
>>>> +     struct mt6360_led *led = container_of(lcdev, struct mt6360_led, flash.led_cdev);
>>>> +     struct mt6360_priv *priv = led->priv;
>>>> +     u32 enable_mask = MT6360_TORCHEN_MASK | MT6360_FLCSEN_MASK(led->led_no);
>>>> +     u32 val = (level) ? MT6360_FLCSEN_MASK(led->led_no) : 0;
>>>> +     u32 prev = priv->fled_torch_used, curr;
>>>> +     int ret;
>>>> +
>>>> +     dev_dbg(lcdev->dev, "[%d] brightness %d\n", led->led_no, level);
>>>> +     if (priv->fled_strobe_used) {
>>>> +             dev_warn(lcdev->dev, "Please disable strobe first [%d]\n", priv->fled_strobe_used);
>>>> +             return -EINVAL;
>>>> +     }
>>>
>>> So... how does its userland interface look like?
>>>
>>
>> 1. set FLED1 brightness
>> # echo 1 > /sys/class/leds/white:flash1/flash_brightness
>> 2. enable FLED1 strobe
>> # echo 1 > /sys/class/leds/white:flash1/flash_strobe
>> 3 . turn off FLED1 strobe (just used to gaurantee the strobe mode
>> flash leds must be turned off)
>> # echo 0 > /sys/class/leds/white:flash1/flash_strobe
> 
> I believe I'd preffer only exposing torch functionality in
> /sys/class/leds. .. strobe can be supported using v4l2 APIs.

Actually having LED flash class without strobe is pointless.
If you looked at led_classdev_flash_register_ext() you would see that
it fails with uninitialized strobe_set op. And V4L2 API for strobing
flash calls strobe_set from LED flash class beneath.

That was the idea behind LED and V4L2 flash API unification - there
is one hardware driver needed, the V4L2 Flash layer just takes over
control over it when needed.

-- 
Best regards,
Jacek Anaszewski

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  reply	other threads:[~2020-09-10 20:25 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-07 10:27 [PATCH v3 0/2] leds: mt6360: Add LED driver for MT6360 Gene Chen
2020-09-07 10:27 ` [PATCH v3 1/2] " Gene Chen
2020-09-08 14:13   ` Dan Murphy
2020-09-08 22:25   ` Pavel Machek
2020-09-09 23:49     ` Gene Chen
2020-09-10 12:29       ` Pavel Machek
2020-09-10 20:23         ` Jacek Anaszewski [this message]
2020-09-10 20:25           ` Pavel Machek
2020-09-10 20:31             ` Jacek Anaszewski
2020-09-09 13:48   ` Andy Shevchenko
2020-09-10  0:11     ` Gene Chen
2020-09-10  8:18       ` Pavel Machek
2020-09-10 11:34         ` Andy Shevchenko
2020-09-10 12:28           ` Pavel Machek
2020-09-10 11:46       ` Andy Shevchenko
2020-09-10 21:42   ` Jacek Anaszewski
2020-09-11  7:05     ` Pavel Machek
2020-09-10 23:24       ` Gene Chen
2020-09-11 21:21         ` Jacek Anaszewski
2020-09-11 20:56       ` Jacek Anaszewski
2020-09-07 10:27 ` [PATCH v3 2/2] dt-bindings: leds: Add bindings for MT6360 LED Gene Chen
2020-09-08 13:55   ` Dan Murphy
2020-09-08 22:22   ` Pavel Machek
2020-09-15 15:51   ` Rob Herring
2020-09-08 14:14 ` [PATCH v3 0/2] leds: mt6360: Add LED driver for MT6360 Dan Murphy
2020-09-09  0:00   ` Gene Chen

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