pwm: lpss-*: Make use of devm_pwmchip_alloc() function

This prepares the pwm-lpss drivers to further changes of the pwm core
outlined in the commit introducing devm_pwmchip_alloc(). There is no
intended semantical change and the driver should behave as before.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/b567ab5dd992e361eb884fa6c2cac11be9c7dde3.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: lpss-*: Don't set driver data

The drivers don't make use of driver data, neither in the variant
pci_get_drvdata() nor as platform_get_drvdata() nor as
dev_get_drvdata(). Drop setting driver data accordingly.

Link: https://lore.kernel.org/r/25671b7562d96b67fd05b3fa6fc76538ddf5914f.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: lpss-platform: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Rename pwm_lpss_probe() --> devm_pwm_lpss_probe()

The pwm_lpss_probe() uses managed resources. Show this to
the users explicitly by adding devm prefix to its name.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: lpss: Use device_get_match_data() to get device data

device_get_match_data() in ACPI case calls similar to the
acpi_match_device(). We may simplify the code and make it
generic by replacing the latter with the former.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Move resource mapping to the glue drivers

Move resource mapping to the glue drivers which helps
to transform pwm_lpss_probe() to pure library function
that may be used by others without need of specific
resource management.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Move exported symbols to PWM_LPSS namespace

Avoid unnecessary pollution of the global symbol namespace by
moving library functions in to a specific namespace and import
that into the drivers that make use of the functions.

For more info: https://lwn.net/Articles/760045/

Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Deduplicate board info data structures

Move the board info structures from the glue drivers to the
common library and hence deduplicate configuration data.

For the Intel Braswell case the ACPI version should be used.
Because switch to ACPI/PCI is done in BIOS while quite likely
the rest of AML code is the same, meaning similar issue might
be observed. There is no bug report due to no PCI enabled device
in the wild, Andy thinks, and only reference boards can be tested,
so nobody really cares about Intel Braswell PCI case.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Simplify using devm_pwmchip_add()

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Set DPM_FLAG_SMART_SUSPEND on Cherry Trail devices

As the comment above the code setting the DPM_FLAG_NO_DIRECT_COMPLETE
flag explains:

/*
* On Cherry Trail devices the GFX0._PS0 AML checks if the controller
* is on and if it is not on it turns it on and restores what it
* believes is the correct state to the PWM controller.
* Because of this we must disallow direct-complete, which keeps the
* controller (runtime)suspended, on resume to avoid 2 issues:
* 1. The controller getting turned on without the linux-pm code
* knowing about this. On devices where the controller is unused
* this causes it to stay on during the next suspend causing high
* battery drain (because S0i3 is not reached)
* 2. The state restoring code unexpectedly messing with the controller
*/

The pm-core must not skip resume to avoid the GFX0._PS0 AML code messing
with the PWM controller behind our back. But leaving the controller
runtime-suspended (skipping runtime-resume + normal-suspend) during
suspend is fine. Set the DPM_FLAG_SMART_SUSPEND flag to allow this.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Use DPM_FLAG_NO_DIRECT_COMPLETE instead of declaring a prepare handler

ACPI LPSS devices use direct-complete style suspend/resume handling by
default. We set the DPM_FLAG_SMART_PREPARE and define a prepare handler
to disable this on Cherry Trail devices.

Clean this up a bit by setting the DPM_FLAG_NO_DIRECT_COMPLETE flag for
Cherry Trail devices, instead of defining a prepare handler.

While at it also improve the comment explaining why this is necessary.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Remove suspend/resume handlers

PWM controller drivers should not restore the PWM state on resume. The
convention is that PWM consumers do this by calling pwm_apply_state(),
so that it can be done at the exact moment when the consumer needs
the state to be stored, avoiding e.g. backlight flickering.

The only in kernel consumers of the pwm-lpss code, the i915 driver
and the pwm-class sysfs interface code both correctly restore the
state on resume, so there is no need to do this in the pwm-lpss code.

More-over the removed resume handler is buggy, since it blindly
restores the ctrl-register contents without setting the update
bit, which is necessary to get the controller to actually use/apply
the restored base-unit and on-time-div values.

Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200903112337.4113-8-hdegoede@redhat.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

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 <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

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

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 <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Add ACPI HID for second PWM controller on Cherry Trail devices

The second PWM controller on Cherry Trail devices uses a separate ACPI
HID: "80862289", add this so that the driver will properly bind to the
second PWM controller.

The second PWM controller is usually not used, the main thing gained by
this is properly putting the PWM controller in D3 on suspend.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: platform: Save/restore the ctrl register over a suspend/resume

On some devices the contents of the ctrl register get lost over a
suspend/resume and the PWM comes back up disabled after the resume.

This is seen on some Bay Trail devices with the PWM in ACPI enumerated
mode, so it shows up as a platform device instead of a PCI device.

If we still think it is enabled and then try to change the duty-cycle
after this, we end up with a "PWM_SW_UPDATE was not cleared" error and
the PWM is stuck in that state from then on.

This commit adds suspend and resume pm callbacks to the pwm-lpss-platform
code, which save/restore the ctrl register over a suspend/resume, fixing
this.

Note that:

1) There is no need to do this over a runtime suspend, since we
only runtime suspend when disabled and then we properly set the enable
bit and reprogram the timings when we re-enable the PWM.

2) This may be happening on more systems then we realize, but has been
covered up sofar by a bug in the acpi-lpss.c code which was save/restoring
the regular device registers instead of the lpss private registers due to
lpss_device_desc.prv_offset not being set. This is fixed by a later patch
in this series.

Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Set enable-bit before waiting for update-bit to go low

At least on cherrytrail, the update bit will never go low when the
enabled bit is not set.

This causes the backlight on my cube iwork8 air tablet to never turn on
again after being turned off because in the pwm_lpss_apply enable path
pwm_lpss_update will fail causing an error exit and the enable-bit to
never get set. Any following pwm_lpss_apply calls will fail the
pwm_lpss_is_updating check.

Since the docs say that the update bit should be set before the
enable-bit, split pwm_lpss_update into setting the update-bit and
pwm_lpss_wait_for_update, and move the pwm_lpss_wait_for_update call
in the enable path to after setting the enable-bit.

Fixes: 10d56a4 ("pwm: lpss: Avoid reconfiguring while UPDATE bit...")
Cc: Ilkka Koskinen <ilkka.koskinen@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Do not export board infos for different PWM types

The PWM LPSS probe drivers just pass a pointer to the exported board
info structures to pwm_lpss_probe() based on device PCI or ACPI ID.

In order to remove the knowledge of specific devices from library part of
the driver and reduce noise in exported namespace just duplicate the
board info structures and stop exporting them.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Add support for runtime PM

To be able to save some power when PWM is not in use, add support for
runtime PM for this driver. This also allows the platform to transition to
low power S0ix states when the system is idle.

Signed-off-by: Huiquan Zhong <huiquan.zhong@intel.com>
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Add more Intel Broxton IDs

Add more Intel Broxton ACPI and PCI IDs to the driver supported devices
list.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Properly split driver to parts

The driver consists of core, PCI, and platform parts. It would be better
to split them into separate files.

The platform driver is now called pwm-lpss-platform. Thus, previously
set CONFIG_PWM_LPSS=m is not enough to build it. But we are on the safe
side since it seems no one from outside Intel is using it for now.

While here, move to use macros module_pci_driver() and
module_platform_driver().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
[thierry.reding: change select to depends on PWM_LPSS, cleanup]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>