kernel/linux.git/drivers/pwm, branch linux-4.20.y

pwm: lpss: Only set update bit if we are actually changing the settings

2018-10-16T11:16:15+00:00

According to the datasheet the update bit must be set if the on-time-div or the base-unit changes. Now that we properly order device resume on Cherry Trail so that the GFX0 _PS0 method no longer exits with an error, we end up with a sequence of events where we are writing the same values twice in a row. First the _PS0 method restores the duty cycle of 0% the GPU driver set on suspend and then the GPU driver first updates just the enabled bit in the pwm_state from 0 to 1, causing us to write the same values again, before restoring the pre-suspend duty-cycle in a separate pwm_apply call. When writing the update bit the second time, without changing any of the values the update bit clears immediately / instantly, instead of staying 1 for a while as usual. After this the next setting of the update bit seems to be ignored, causing the restoring of the pre-suspend duty-cycle to not get applied. This makes the backlight come up with a 0% dutycycle after suspend/resume. Any further brightness changes after this do work. This commit moves the setting of the update bit into pwm_lpss_prepare() and only sets the bit if we have actually changed any of the values. This avoids the setting of the update bit the second time we configure the PWM to 0% dutycycle, this fixes the backlight coming up with 0% duty-cycle after a suspend/resume. Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding

pwm: lpss: Force runtime-resume on suspend on Cherry Trail

2018-10-16T11:15:57+00:00

On Cherry Trail devices under Windows the PWM controller used for the backlight is considered part of the GPU even though it is part of the LPSS block and thus is an entirely different independent hardware unit. Because of this on Cherry Trail the GPU's (GFX0 ACPI node) _PS3 and _PS0 methods save and restore the PWM controller registers. If userspace blanks the screen before suspending, such as e.g. GNOME does, then the PWM controller will be runtime-suspended when the suspend starts. This causes the GFX0 _PS? methods to save a value of 0xffffffff for the PWM control register and to restore this value on resume. 0xffffffff is not a valid value for the register and writing this causes problems such as e.g. a flickering backlight. This commit adds a prepare method to the dev_pm_ops and makes it return 0 on Cherry Trail devices forcing a runtime-resume before other device's suspend methods run. This fixes the reading and writing back of 0xffffffff. Since we now always runtime-resume the device on suspend, it will be resumed on resume too and we no longer need to check for the GFX0 _PS0 method having resumed it underneath us, so this commit removes the now no longer necessary complete dev_pm_op. Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding

pwm: Enable TI ECAP driver for ARCH_K3

2018-10-16T11:14:52+00:00

K3 devices have the same ECAP IP as OMAP SoCs. Enable driver to be built for K3 devices. Also, drop reference to AM33xx in help text, as IP is found on multiple TI SoCs. Signed-off-by: Vignesh R Signed-off-by: Thierry Reding

pwm: Send a uevent on the pwmchip device upon channel sysfs (un)export

2018-10-12T11:51:33+00:00

This patch sends a uevent (KOBJ_CHANGE) on the pwmchipN device, everytime a pwmX channel has been exported/unexported via sysfs. This allows udev to implement rules on such events, like: SUBSYSTEM=="pwm*", PROGRAM="/bin/sh -c '\ chown -R root:gpio /sys/class/pwm && chmod -R 770 /sys/class/pwm;\ chown -R root:gpio /sys/devices/platform/soc/*.pwm/pwm/pwmchip* && chmod -R 770 /sys/devices/platform/soc/*.pwm/pwm/pwmchip*\ '" This is a replacement patch for commit 7e5d1fd75c3d ("pwm: Set class for exported channels in sysfs"), see [1]. basic testing: $ udevadm monitor --environment & $ echo 0 > /sys/class/pwm/pwmchip0/export KERNEL[197.321736] change /devices/.../pwm/pwmchip0 (pwm) ACTION=change DEVPATH=/devices/.../pwm/pwmchip0 EXPORT=pwm0 SEQNUM=2045 SUBSYSTEM=pwm [1] https://lkml.org/lkml/2018/9/25/713 Signed-off-by: Fabrice Gasnier Tested-by: Gottfried Haider Tested-by: Michal Vokáč Signed-off-by: Thierry Reding

Revert "pwm: Set class for exported channels in sysfs"

2018-10-12T11:51:11+00:00

This reverts commit 7e5d1fd75c3dde9fc10c4472b9368089d1b81d00 ("pwm: Set class for exported channels in sysfs") as it causes regression with multiple pwm chip[1], when exporting a pwm channel (echo X > export): - ABI (Documentation/ABI/testing/sysfs-class-pwm) states pwmX should be created in /sys/class/pwm/pwmchipN/pwmX - Reverted patch causes new entry to be also created directly in /sys/class/pwm/pwmX - 1st time, exporting pwmX will create an entry in /sys/class/pwm/pwmX - class attributes are added under pwmX folder, such as export, unexport npwm, symlinks. This is wrong as it belongs to pwmchipN. It may cause bad behavior and report wrong values. - when another export happens on another pwmchip, it can't be created (e.g. -EEXIST). This is causing the issue with multiple pwmchip. Example on stm32 (stm32429i-eval) platform: $ ls /sys/class/pwm pwmchip0 pwmchip4 $ cd /sys/class/pwm/pwmchip0/ $ echo 0 > export $ ls /sys/class/pwm pwm0 pwmchip0 pwmchip4 $ cd /sys/class/pwm/pwmchip4/ $ echo 0 > export sysfs: cannot create duplicate filename '/class/pwm/pwm0' ...Exception stack follows... This is also seen on other platform [2] [1] https://lkml.org/lkml/2018/9/25/713 [2] https://lkml.org/lkml/2018/9/25/447 Signed-off-by: Fabrice Gasnier Tested-by: Gottfried Haider Tested-by: Michal Vokáč Signed-off-by: Thierry Reding

pwm: Use SPDX identifier for Renesas drivers

2018-10-12T11:35:45+00:00

Signed-off-by: Wolfram Sang Reviewed-by: Simon Horman Signed-off-by: Thierry Reding

pwm: lpss: Add get_state callback

2018-10-12T10:33:02+00:00

Add a get_state callback so that the initial state correctly reflects the actual hardware state. Cc: Andy Shevchenko Acked-by: Jani Nikula Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding

pwm: lpss: Release runtime-pm reference from the driver's remove callback

2018-10-12T10:32:12+00:00

For each pwm output which gets enabled through pwm_lpss_apply(), we do a pm_runtime_get_sync(). This commit adds pm_runtime_put() calls to pwm_lpss_remove() to balance these when the driver gets removed with some of the outputs still enabled. Fixes: f080be27d7d9 ("pwm: lpss: Add support for runtime PM") Acked-by: Andy Shevchenko Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding

pwm: lpss: Check PWM powerstate after resume on Cherry Trail devices

2018-10-12T10:31:58+00:00

The _PS0 method for the integrated graphics on some Cherry Trail devices (observed on a HP Pavilion X2 10-p0XX) turns on the PWM chip (puts it in D0), causing an inconsistency between the state the pm-core thinks it is in (left runtime suspended as it was before the suspend/resume) and the state it actually is in. Interestingly enough this is done on a device where the pwm controller is not used for the backlight at all, since it uses an eDP panel. On devices where the PWM is used this is not a problem since we will resume it ourselves anyways. This inconsistency causes us to never suspend the pwm controller again, which causes the device to not be able to reach S0ix states when suspended. This commit adds a resume-complete handler, which when we think the device is still run-time suspended checks the actual power-state and if necessary updates the rpm-core's internal state. This fixes the Pavilion X2 10-p0XX not reaching S0ix states when suspended. Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding

pwm: lpss: Move struct pwm_lpss_chip definition to the header file

2018-10-12T10:31:01+00:00

Move struct pwm_lpss_chip definition from pwm-lpss.c to pwm-lpss.h, so that the pci/platform drivers can access the info member (struct pwm_lpss_boardinfo *). This is a preparation patch for adding platform specific quirks, which the drivers need access to, to pwm_lpss_boardinfo. Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede Signed-off-by: Thierry Reding