From: Enric Balletbo Serra <eballetbo@gmail.com>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>,
Doug Anderson <dianders@google.com>, Pavel Machek <pavel@ucw.cz>,
Rob Herring <robh+dt@kernel.org>,
Jingoo Han <jingoohan1@gmail.com>,
Richard Purdie <rpurdie@rpsys.net>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Brian Norris <briannorris@google.com>,
Guenter Roeck <groeck@google.com>,
Lee Jones <lee.jones@linaro.org>,
Alexandru Stan <amstan@google.com>,
linux-leds@vger.kernel.org,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
kernel@collabora.com
Subject: Re: [PATCH v3 0/4] backlight: pwm_bl: support linear interpolation and brightness to human eye
Date: Tue, 20 Mar 2018 13:13:20 +0100 [thread overview]
Message-ID: <CAFqH_51E+9L2fuTY7Zo3=B2fUmL=pJtg7wz3GdN5wxhpqV8p0g@mail.gmail.com> (raw)
In-Reply-To: <20180320112212.2mwthxug3pu7uqgg@holly.lan>
Hi Daniel,
2018-03-20 12:22 GMT+01:00 Daniel Thompson <daniel.thompson@linaro.org>:
> On Mon, Mar 19, 2018 at 05:04:31PM +0100, Enric Balletbo Serra wrote:
>> Hi Daniel,
>>
>> Gentle ping for this series, there is any possibility you have a
>> chance to review it? Let me know if you want I change something.
>
> I haven't got it in my TODO backlog... which means either I mistakenly
> deleted it when it went through originally or that I deliberately deleted
> it because I thought a v4 was coming along soon.
>
> I could go diving through the archives if I need to but were there other
> pending changes for this patchset?
>
Unless I am missing something there isn't pending changes requested.
1/4 I addressed your latest comments in this version.
2/4 Has been acked by Rob Herring
3/4 I did not receive feedback but iirc we agreed to use a pre-computed table.
4/4 Is already acked by you.
Regards,
Enric
>
> Daniel.
>
>
>>
>> Thanks,
>> Enric
>>
>> 2018-02-08 12:30 GMT+01:00 Enric Balletbo i Serra
>> <enric.balletbo@collabora.com>:
>> > Dear all,
>> >
>> > This series is a third patchset integrating the requested changes.
>> >
>> > The first and second patch what tries to solve is the problem of
>> > granularity for high resolution PWMs. The idea is simple interpolate
>> > between 2 brightness values so we can have a high PWM duty cycle (a
>> > 16 bits PWM is up to 65535 possible steps) without having to list
>> > out every possible value in the dts. I think that this patch is
>> > required to not break backward compability, to be more flexible and
>> > also extend the functionality to be able to use high resolution PWM
>> > with enough steps to have a good UI experience in userspace.
>> >
>> > The thirth and fourth patch is a bit more ambicious, the idea is let
>> > decide the driver the brightness-levels required in function of the PWM
>> > resolution. To do this create a brightness-levels table filled with the
>> > CIE 1931 algorithm values to convert brightness to PWM duty cycle.
>> >
>> > More detailed info is available in the commit message of every patch.
>> >
>> > Both functionalities were tested on a Samsung Chromebook Plus (that has
>> > a 16 bits PWM) and a SL50 device (with a 8 bits PWM)
>> >
>> > Waiting for your feedback.
>> >
>> > Best regards,
>> >
>> > Enric Balletbo i Serra (4):
>> > backlight: pwm_bl: linear interpolation between brightness-levels
>> > dt-bindings: pwm-backlight: add a num-interpolation-steps property.
>> > backlight: pwm_bl: compute brightness of LED linearly to human eye.
>> > dt-bindings: pwm-backlight: move brightness-levels to optional.
>> >
>> > .../bindings/leds/backlight/pwm-backlight.txt | 34 ++-
>> > drivers/video/backlight/pwm_bl.c | 232 +++++++++++++++++++--
>> > 2 files changed, 246 insertions(+), 20 deletions(-)
>> >
>> > --
>> > 2.15.1
>> >
next prev parent reply other threads:[~2018-03-20 12:13 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-08 11:30 [PATCH v3 0/4] backlight: pwm_bl: support linear interpolation and brightness to human eye Enric Balletbo i Serra
2018-02-08 11:30 ` [PATCH v3 1/4] backlight: pwm_bl: linear interpolation between brightness-levels Enric Balletbo i Serra
2018-04-06 15:46 ` Daniel Thompson
2018-02-08 11:30 ` [PATCH v3 2/4] dt-bindings: pwm-backlight: add a num-interpolation-steps property Enric Balletbo i Serra
2018-02-18 22:49 ` Rob Herring
2018-02-08 11:30 ` [PATCH v3 3/4] backlight: pwm_bl: compute brightness of LED linearly to human eye Enric Balletbo i Serra
2018-04-06 15:51 ` Daniel Thompson
2019-06-07 22:19 ` Matthias Kaehlcke
2019-06-08 21:02 ` Pavel Machek
2019-06-10 10:00 ` Enric Balletbo i Serra
2019-06-10 20:39 ` Matthias Kaehlcke
2019-06-10 21:02 ` Enric Balletbo i Serra
2019-06-10 21:54 ` Matthias Kaehlcke
2019-06-10 20:52 ` Matthias Kaehlcke
2019-06-11 10:49 ` Daniel Thompson
2019-06-11 16:55 ` Brian Norris
2019-06-11 22:30 ` Matthias Kaehlcke
2019-06-12 9:54 ` Pavel Machek
2019-06-12 11:03 ` Daniel Thompson
2019-06-12 19:26 ` Matthias Kaehlcke
2019-06-12 19:47 ` Daniel Thompson
2019-06-12 21:59 ` Matthias Kaehlcke
2019-06-17 13:01 ` Pavel Machek
2019-06-17 20:03 ` Matthias Kaehlcke
[not found] ` <20180208113032.27810-1-enric.balletbo-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
2018-02-08 11:30 ` [PATCH v3 4/4] dt-bindings: pwm-backlight: move brightness-levels to optional Enric Balletbo i Serra
2018-03-19 16:04 ` [PATCH v3 0/4] backlight: pwm_bl: support linear interpolation and brightness to human eye Enric Balletbo Serra
2018-03-20 11:22 ` Daniel Thompson
2018-03-20 12:13 ` Enric Balletbo Serra [this message]
2018-04-06 15:54 ` Daniel Thompson
2018-04-09 8:17 ` Lee Jones
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