linux-kernel - [PATCH v4 0/3] leds: rgb: leds-qcom-lpg: PWM fixes

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Message-Id: <20250305-leds-qcom-lpg-fix-max-pwm-on-hi-res-v4-0-bfe124a53a9f@linaro.org>
Date: Wed, 05 Mar 2025 15:09:03 +0200
From: Abel Vesa <abel.vesa@...aro.org>
To: Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>, 
 Anjelique Melendez <anjelique.melendez@....qualcomm.com>
Cc: Uwe Kleine-König <ukleinek@...nel.org>, 
 Kamal Wadhwa <quic_kamalw@...cinc.com>, 
 Jishnu Prakash <jishnu.prakash@....qualcomm.com>, 
 Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>, Johan Hovold <johan@...nel.org>, 
 Sebastian Reichel <sre@...nel.org>, Pavel Machek <pavel@....cz>, 
 linux-leds@...r.kernel.org, linux-pwm@...r.kernel.org, 
 linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Abel Vesa <abel.vesa@...aro.org>, stable@...r.kernel.org
Subject: [PATCH v4 0/3] leds: rgb: leds-qcom-lpg: PWM fixes

The PWM allow configuring the PWM resolution from 8 bits PWM
values up to 15 bits values, for the Hi-Res PWMs, and then either
6-bit or 9-bit for the normal PWMs. The current implementation loops
through all possible resolutions (PWM sizes), for the PWM subtype, on top
of the already existing process of determining the prediv, exponent and
refclk.

The first and second issues are related to capping the computed PWM
value.

The third issue is that it uses the wrong maximum possible PWM
value for determining the best matched period.

Fix all of them.

Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
---
Changes in v4:
- Rebased on next-20250305
- Re-worded the commit messages for the first two patches to include an
  example that should better explain what the issue that is being fixed
  is. As per Uwe's request.
- Link to v3: https://lore.kernel.org/r/20250303-leds-qcom-lpg-fix-max-pwm-on-hi-res-v3-0-62703c0ab76a@linaro.org

Changes in v3:
- Added a new patch that fixes the normal PWMs, since they now support
  6-bit resolution as well. Added it as first patch.
- Re-worded the second patch. Included Bjorn's suggestion and R-b tag.
- Link to v2: https://lore.kernel.org/r/20250226-leds-qcom-lpg-fix-max-pwm-on-hi-res-v2-0-7af5ef5d220b@linaro.org

Changes in v2:
- Re-worded the commit to drop the details that are not important
  w.r.t. what the patch is fixing.
- Added another patch which fixes the resolution used for determining
  best matched period and PWM config.
- Link to v1: https://lore.kernel.org/r/20250220-leds-qcom-lpg-fix-max-pwm-on-hi-res-v1-1-a161ec670ea5@linaro.org

---
Abel Vesa (3):
      leds: rgb: leds-qcom-lpg: Fix pwm resolution max for normal PWMs
      leds: rgb: leds-qcom-lpg: Fix pwm resolution max for Hi-Res PWMs
      leds: rgb: leds-qcom-lpg: Fix calculation of best period Hi-Res PWMs

 drivers/leds/rgb/leds-qcom-lpg.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
---
base-commit: 7ec162622e66a4ff886f8f28712ea1b13069e1aa
change-id: 20250220-leds-qcom-lpg-fix-max-pwm-on-hi-res-067e8782a79b

Best regards,
-- 
Abel Vesa <abel.vesa@...aro.org>