pwm: img: fix pwm clock lookup

22e8e19 has introduced a regression in the imgchip->pwm_clk lookup, whereas
the clock name has also been renamed to "imgchip". This causes the driver
failing to load:

[ 0.546905] img-pwm 18101300.pwm: failed to get imgchip clock
[ 0.553418] img-pwm: probe of 18101300.pwm failed with error -2

Fix this lookup by reverting the clock name back to "pwm".

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>
Link: https://lore.kernel.org/r/20240320083602.81592-1-wigyori@uid0.hu
Fixes: 22e8e19a46f7 ("pwm: img: Rename variable pointing to driver private data")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: img: Make use of devm_pwmchip_alloc() function

This prepares the pwm-img driver 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.

Link: https://lore.kernel.org/r/d99e00af2ff09cd3587d9a7c51dc8e0e13f85208.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: img: Prepare removing pwm_chip from driver data

This prepares the driver for further changes that will drop struct
pwm_chip chip from struct img_pwm_chip. Use the pwm_chip as driver data
instead of the img_pwm_chip to get access to the pwm_chip in
img_pwm_remove() and the PM callbacks without using imgchip->chip.

Link: https://lore.kernel.org/r/2ddf76d127f69eca7d9faa6475091e432e890ac9.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: img: Make use of pwmchip_parent() accessor

struct pwm_chip::dev is about to change. To not have to touch this
driver in the same commit as struct pwm_chip::dev, use the accessor
function provided for exactly this purpose.

Link: https://lore.kernel.org/r/bbea7e6e4c5412c6b0773faa9f165b6311cd53b6.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: img: Drop write-only variable from driver private data

struct img_pwm_chip::dev is only assigned to, but the member variable is
never used. So drop it.

Link: https://lore.kernel.org/r/7b7de753caa453c7fe591228c9a45d0baf8b5878.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: Stop referencing pwm->chip

Drivers have access to the chip via a function argument already, so
there is no need to reference it via the PWM device.

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

pwm: Use device_get_match_data()

Use preferred device_get_match_data() instead of of_match_device() to
get the driver match data. With this, adjust the includes to explicitly
include the correct headers.

As these drivers only do DT based matching, of_match_device() will never
return NULL if we've gotten to probe(). Therefore, the NULL check and
error returns can be dropped.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Manage owner assignment implicitly for drivers

Instead of requiring each driver to care for assigning the owner member
of struct pwm_ops, handle that implicitly using a macro. Note that the
owner member has to be moved to struct pwm_chip, as the ops structure
usually lives in read-only memory and so cannot be modified.

The upside is that new low level drivers cannot forget the assignment and
save one line each. The pwm-crc driver didn't assign .owner, that's not
a problem in practice though as the driver cannot be compiled as a
module.

Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # Intel LPSS
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com> # pwm-{bcm,brcm}*.c
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> # sun4i
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Acked-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> # pwm-visconti
Acked-by: Heiko Stuebner <heiko@sntech.de> # pwm-rockchip
Acked-by: Michael Walle <michael@walle.cc> # pwm-sl28cpld
Acked-by: Neil Armstrong <neil.armstrong@linaro.org> # pwm-meson
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230804142707.412137-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: 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: img: Use regmap_clear_bits and regmap_set_bits where applicable

Found using coccinelle and the following semantic patch:

@@
expression map, reg, bits;
@@

- regmap_update_bits(map, reg, bits, bits)
+ regmap_set_bits(map, reg, bits)

@@
expression map, reg, bits;
@@

- regmap_update_bits(map, reg, bits, 0)
+ regmap_clear_bits(map, reg, bits)

Link: https://lore.kernel.org/r/20221115111347.3705732-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: Rename variable pointing to driver private data

Status quo is that variables of type struct img_pwm_chip * are named
"pwm_chip", "pwm" or "chip" which are all not optimal because there is a
struct pwm_chip in the core, usually only struct pwm_device * variables are
named "pwm" and "chip" is usually used for variabled of type struct
pwm_chip *.

So consistently use the same and non-conflicting name "imgchip".

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

pwm: img: Use only a single idiom to get a runtime PM reference

Currently there are two very similar approaches in use by this driver:
img_pwm_config() uses pm_runtime_get_sync() and calls
pm_runtime_put_autosuspend() in the error path; img_pwm_enable() calls
pm_runtime_resume_and_get() which already puts the reference in its own
error path.

Align pm_runtime usage and use the same idiom in both locations.

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

pwm: img: Implement .apply() callback

To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply(). This just pushes down a slightly
optimized variant of how legacy drivers are handled in the core.

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

pwm: img: Don't check the return code of pwmchip_remove()

pwmchip_remove() returns always 0. Don't use the value to make it
possible to eventually change the function to return void. Also the
driver core ignores the return value of pwm_imx_tpm_remove().

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

pwm: img: Don't modify HW state in .remove() callback

A consumer is expected to disable a PWM before calling pwm_put(). And if
they didn't there is hopefully a good reason (or the consumer needs
fixing). Also if disabling an enabled PWM was the right thing to do,
this should better be done in the framework instead of in each low level
driver.

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

pwm: img: Fix PM reference leak in img_pwm_enable()

pm_runtime_get_sync will increment pm usage counter even it failed.
Forgetting to putting operation will result in reference leak here.
Fix it by replacing it with pm_runtime_resume_and_get to keep usage
counter balanced.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Always allocate PWM chip base ID dynamically

Since commit 5e5da1e9fbee ("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.

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

pwm: img: Convert to devm_platform_ioremap_resource()

Use devm_platform_ioremap_resource() to simplify code.

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

pwm: img: Fix null pointer access in probe

dev_get_drvdata() is called in img_pwm_runtime_resume() before the
driver data is set.
When pm_runtime_enabled() returns false in img_pwm_probe() it calls
img_pwm_runtime_resume() which results in a null pointer access.

This patch fixes the problem by setting the driver data earlier in the
img_pwm_probe() function.

This crash was seen when booting the Imagination Technologies Creator
Ci40 (Marduk) with kernel 5.4 in OpenWrt.

Fixes: e690ae526216 ("pwm: img: Add runtime PM")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case

Even in failed case of pm_runtime_get_sync(), the usage_count is
incremented. In order to keep the usage_count with correct value call
appropriate pm_runtime_put().

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 178

Based on 1 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 as published by
the free software foundation either version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 24 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.162703968@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

pwm: img: Turn final 'else if' into 'else' in img_pwm_config

When building with -Wsometimes-uninitialized, Clang warns:

drivers/pwm/pwm-img.c:126:13: error: variable 'timebase' is used
uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]

The final else if functions as an else; make that explicit so that Clang
understands that timebase cannot be used uninitialized.

Link: https://github.com/ClangBuiltLinux/linux/issues/400
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: Add runtime PM

Add runtime PM to disable the clocks when the h/w is not in use.

Signed-off-by: Ed Blake <ed.blake@sondrel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: Add suspend / resume handling

The power may be disabled during suspend, so implement suspend and
resume callbacks to save and restore register state.

Signed-off-by: Ed Blake <ed.blake@sondrel.com>
[thierry.reding@gmail.com: guard using PM_SLEEP instead of PM]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: Test clock rate to avoid division by 0

The clk API may return 0 on clk_get_rate(), so we should check the
result before using it as a divisor.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: img: Impose upper and lower timebase steps value

The PWM hardware on Pistachio platform has a maximum timebase steps
value to 255. To fix it, let's introduce a compatible-specific
data structure to contain the SoC-specific details and use it to
specify a maximum timebase.

Also, let's limit the minimum timebase to 16 steps, to allow a sane
range of duty cycle steps.

Fixes: 277bb6a29e00 ("pwm: Imagination Technologies PWM DAC driver")
Signed-off-by: Naidu Tellapati <naidu.tellapati@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Imagination Technologies PWM DAC driver

The Pistachio SOC from Imagination Technologies includes a Pulse Width
Modulation DAC which produces 1 to 4 digital bit-outputs which represent
digital waveforms. These PWM outputs are primarily in charge of controlling
backlight LED devices.

Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Sai Masarapu <Sai.Masarapu@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
[thierry.reding: fixup license header as discussed on list]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>