From: Hans de Goede <hdegoede@redhat.com>
To: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Pavel Machek <pavel@ucw.cz>
Cc: Yauhen Kharuzhy <jekhor@gmail.com>,
linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org
Subject: Re: [PATCH v2 1/2] leds: Add Intel Cherry Trail Whiskey Cove PMIC LEDs
Date: Sat, 16 Feb 2019 23:03:08 +0100 [thread overview]
Message-ID: <fc178a78-8e12-1892-3fde-21333e65667c@redhat.com> (raw)
In-Reply-To: <2d5c6f50-c41f-655c-ab03-0c66aa911a27@gmail.com>
Hi,
On 2/16/19 10:54 PM, Jacek Anaszewski wrote:
> On 2/16/19 8:37 PM, Pavel Machek wrote:
>> Hi!
>>
>>>>>>> I think that should work fine, which means that we can use the timer and
>>>>>>> pattern trigger support for the blinking and breathing modes.
>>>>>>>
>>>>>>> That still leaves the switching between user and hw-control modes,
>>>>>>> as discussed the hw-controlled mode could be modelled as a new "hardware"
>>>>>>> trigger, but then we cannot choose between on/blink/breathing when
>>>>>>> in hw-controlled mode. As Pavel mentioned, that would require some
>>>>>>> sort of composed trigger, where we have both the hardware and
>>>>>>> timer triggers active for example.
>>>>>>>
>>>>>>> I think it might be easier to just allow turning on/off the hardware
>>>>>>> control mode through a special "hardware_control" sysfs attribute and
>>>>>>> then use the existing timer and pattern triggers for blinking / breathing.
>>>>>>
>>>>>> Pattern trigger exposes pattern file by default and hw_pattern if
>>>>>> pattern_set/get ops are provided. Writing them enables software and
>>>>>> hardware pattern respectively.
>>>>>
>>>>> This is not about software vs hardware pattern.
>>>>>
>>>>> There are 2 *orthogonal*, separate problems/challenges with this LED controller:
>>>>>
>>>>> 1) It has hardware blinking and breathing, as discussed this can be
>>>>> controlled through the timer and pattern triggers, so this problem
>>>>> is solved.
>>>>>
>>>>> 2) It has 2 operating modes:
>>>>>
>>>>> a) Automatic/hardware controlled, in this mode the LED is turned
>>>>> off or on (where on can be continues on, blinking or breathing)
>>>>> by the hardware itself, when in this mode we / userspace is not
>>>>> in control of the LED
>>>>>
>>>>> b) Manual/user controlled mode, in this mode we / userspace can
>>>>> control of the LED.
>>>>>
>>>>> Currently there is no API in the ledclass to switch a LED from
>>>>> automatic controlled to user controlled and back, This is what
>>>>> the proposed hardware trigger was for, to switch to automatic
>>>>> mode. A problem with this is that we still want to be able
>>>>> to chose between continues on, blinking or breathing (when on),
>>>>> configure the max brightness, etc.
>>>>
>>>> Yes, we do have the API to switch a LED from automatic (hardware
>>>> accelerated) control to software control and back. This is pattern
>>>> trigger, which exposes two files for setting pattern: pattern
>>>> and hw_pattern. Writing pattern file switches the device to software
>>>> control mode and writing hw_pattern switches it to the hardware control,
>>>> with the possibility of defining device specific ABI syntax to enable
>>>> particular pattern (blinking, breathing or event permanently on
>>>> in case of this device).
>>>
>>> OK, I see. So we would use the hw_pattern for this and the driver
>>> would implement the pattern_set led_classdev callback.
>>>
>>> The pattern_set callback would then expect 6 brightness/time tuples
>>> with the following meaning for the time part of each tupple
>>>
>>> tupple0: charging blinking_on_time
>>> tupple1: charging blinking_off_time
>>> tupple2: charging breathing_time
>>> tupple3: manual blinking_on_time
>>> tupple4: manual blinking_off_time
>>> tupple5: manual breathing_time
>>>
>>> Where only the times in tupple 0-2; or the times in 3-5 can be
>>> non-zero. Having non zero times for both some charging and some
>>> manual values is not allowed.
>>>
>>> If a breathing time is set, none of the other times may be non
>>> 0. If blinkig_on and blinking_off are used then breathing_time
>>> must be 0.
>>>
>>> When configured to blink then blinking_off must be either 0
>>> (continuously on); or it must be the same as blinking_on.
>>>
>>>
>>> I believe this will work, does this sound ok to you ?
>>
>> I don't pretend to fully understand it, _but_ hw_pattern should really
>> describe the pattern LED should do, not whether it reacts to charging
>> or not.
>
> This is hardware specific and is supposed to have dedicated ABI
> documentation. There's no reason to introduce new mechanisms when
> existing ones fit. It will still describe a pattern but activated
> on some condition.
Right, but we can control the condition, so either we need to make
the condition part of the pattern as in my recent proposal with:
tupple0: charging blinking_on_time
tupple1: charging blinking_off_time
tupple2: charging breathing_time
tupple3: manual blinking_on_time
tupple4: manual blinking_off_time
tupple5: manual breathing_time
As hw_pattern ABI; or we need to add an extra sysfs file to
set the condition.
So do you prefer the driver to code the condition into the hw_pattern
(see above); or do you prefer a separate sysfs attribute for the condition?
Regards,
Hans
next prev parent reply other threads:[~2019-02-16 22:03 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-12 20:58 [PATCH v2 0/2] Intel Cherry Trail Whiskey Cove LEDs support Yauhen Kharuzhy
2019-02-12 20:59 ` [PATCH v2 1/2] leds: Add Intel Cherry Trail Whiskey Cove PMIC LEDs Yauhen Kharuzhy
2019-02-13 22:43 ` Hans de Goede
2019-02-13 23:07 ` Pavel Machek
2019-02-13 23:25 ` Hans de Goede
2019-02-13 23:38 ` Pavel Machek
2019-02-14 9:57 ` Hans de Goede
2019-02-14 11:14 ` Pavel Machek
2019-02-14 11:31 ` Hans de Goede
2019-02-14 12:28 ` Pavel Machek
2019-02-15 21:41 ` Jacek Anaszewski
2019-02-15 23:26 ` Pavel Machek
2019-02-14 21:46 ` Jacek Anaszewski
2019-02-14 23:03 ` Pavel Machek
2019-02-15 7:27 ` Yauhen Kharuzhy
2019-02-15 21:43 ` Jacek Anaszewski
2019-02-16 11:26 ` Yauhen Kharuzhy
2019-02-15 11:27 ` Hans de Goede
2019-02-15 13:02 ` Pavel Machek
2019-02-15 21:42 ` Jacek Anaszewski
2019-02-15 22:26 ` Hans de Goede
2019-02-15 22:31 ` Jacek Anaszewski
2019-02-15 23:14 ` Hans de Goede
2019-02-16 17:02 ` Jacek Anaszewski
2019-02-16 19:01 ` Hans de Goede
2019-02-16 19:37 ` Pavel Machek
2019-02-16 20:55 ` Hans de Goede
2019-02-17 0:08 ` Pavel Machek
2019-02-17 14:10 ` Hans de Goede
2019-02-17 17:45 ` Pavel Machek
2019-02-18 11:12 ` Hans de Goede
2019-02-18 21:59 ` Jacek Anaszewski
2019-02-16 21:54 ` Jacek Anaszewski
2019-02-16 22:03 ` Hans de Goede [this message]
2019-02-17 12:40 ` Jacek Anaszewski
2019-02-14 11:28 ` Pavel Machek
2019-02-14 21:34 ` Yauhen Kharuzhy
2019-02-14 6:55 ` Yauhen Kharuzhy
2019-02-14 10:04 ` Hans de Goede
2019-02-12 20:59 ` [PATCH v2 2/2] mfd: Add leds MFD cell for intel_soc_pmic_chtwc Yauhen Kharuzhy
2019-02-13 21:24 ` Jacek Anaszewski
2019-03-20 9:56 ` Lee Jones
2019-03-20 9:57 ` Lee Jones
2019-04-21 19:28 ` [PATCH v2 0/2] Intel Cherry Trail Whiskey Cove LEDs support Hans de Goede
2019-04-24 18:32 ` Yauhen Kharuzhy
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