pwm: stm32: Make use of devm_pwmchip_alloc() function

This prepares the pwm-stm32 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/59e5dfff2b878cc8590e286572672e4f10e35380.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: stm32: Change prototype of helper that detects npwm to prepare further changes

When the stm32 pwm driver is converted to pwmchip_alloc(), the number of
available PWM lines must be known before the driver private data can be
allocated. So rework the helper function that determines this number to
not take the driver private data struct as input parameter.

Link: https://lore.kernel.org/r/13d4d3e90a9ee1bcd04674dfdc16f242615b8320.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: stm32: Prepare removing pwm_chip from driver data

This prepares the driver for further changes that will drop struct
pwm_chip chip from struct stm32_pwm. Use the pwm_chip as driver
data instead of the stm32_pwm to get access to the pwm_chip in
stm32_pwm_suspend() without using priv->chip.

Link: https://lore.kernel.org/r/3db96cd915d9d8fc350a7193c0d55dd109b1f035.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: stm32: Change prototype of a helper to prepare further changes

This prepares the driver for further changes that will make it harder to
determine the pwm_chip from a given stm32_pwm. To just not have to do
that, rework stm32_pwm_raw_capture() to take a pwm_chip.

Link: https://lore.kernel.org/r/33790c64563cb0434d7156d96f189c6037b3eb0b.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: stm32: Simplify code to determine the pwmchip's parent device

There is already a pointer to the pwmchip, make use of it directly
instead of using the struct stm32_pwm *priv just obtained from it. This
also has the advantage of not using struct stm32_pwm::chip any more
which will be dropped soon.

Link: https://lore.kernel.org/r/54ace92a3c02d22f15a79c7ecf00c29f28386a33.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: stm32: Fix enable count for clk in .probe()

Make the driver take over hardware state without disabling in .probe()
and enable the clock for each enabled channel.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
[ukleinek: split off from a patch that also implemented .get_state()]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Implement .get_state()

Implement the &pwm_ops->get_state callback so drivers can inherit PWM
state set by the bootloader.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
[ukl: split off from a patch that also fixes clk enable count in .probe()]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Use hweight32 in stm32_pwm_detect_channels

Use hweight32() to count the CCxE bits in stm32_pwm_detect_channels().
Since the return value is assigned to chip.npwm, change it to unsigned
int as well.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Make ch parameter unsigned

The channel parameter is only ever set to pwm->hwpwm.
Make it unsigned int as well.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Replace write_ccrx with regmap_write

The TIM_CCR1...4 registers are consecutive, so replace the switch
case with a simple calculation. Since ch is known to be in the 0...3
range (it is set to hwpwm < npwm <= 4), drop the unnecessary error
handling. The return value was not checked anyway. What remains does
not warrant keeping the write_ccrx() function around, so instead call
regmap_write() directly at the singular call site.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Use DEFINE_SIMPLE_DEV_PM_OPS for PM functions

This macro has the advantage over SIMPLE_DEV_PM_OPS that we don't have to
care about when the functions are actually used, so the corresponding
__maybe_unused can be dropped.

Also make use of pm_ptr() to discard all PM related stuff if CONFIG_PM
isn't enabled.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
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: stm32: Simplify using devm_pwmchip_add()

This allows to drop the platform_driver's remove function.

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

pwm: stm32: 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: stm32: Enforce settings for PWM capture

The PWM capture assumes that the input selector is set to default
input and that the slave mode is disabled. Force reset state for
TISEL and SMCR registers to match this requirement.

Note that slave mode disabling is not a pre-requisite by itself
for capture mode, as hardware supports it for PWM capture.
However, the current implementation of the driver does not
allow slave mode for PWM capture. Setting slave mode for PWM
capture results in wrong capture values.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: 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: stm32: 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)

Tested-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20221115111347.3705732-6-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: Simplify all drivers with explicit of_pwm_n_cells = 3

With the previous commit there is no need for the lowlevel driver any
more to specify it it uses two or three cells. So simplify accordingly.

The only non-trival change affects the pwm-rockchip driver: It used to only
support three cells if the hardware supports polarity. Now the default
number depends on the device tree which has to match hardware anyhow
(and if it doesn't the error is just a bit delayed as a PWM handle with
an inverted setting is catched when pwm_apply_state() is called).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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: stm32: Remove automatic output enable

Don't use AOE (automatic output enable) by default. In case of break
events, PWM is automatically re-enabled on next PWM cycle otherwise.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Pass breakinput instead of its values

Instead of passing the individual values of the breakpoint, pass a
pointer to the breakpoint.

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

pwm: stm32: Remove clutter from ternary operator

Remove usage of the ternary operator to assign values for register
fields. Instead, parameterize the register and field offset macros
and pass the index to them.

This removes clutter and improves readability.

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

pwm: stm32: Validate breakinput data from DT

Both index and level can only be either 0 or 1 and the filter value is
limited to values between (and including) 0 and 15. Validate that the
device tree node contains values that are within these ranges.

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

pwm: stm32: Add power management support

Add suspend/resume PM sleep ops. When going to low power, enforce the PWM
channel isn't active. Let the PWM consumers disable it during their own
suspend sequence, see [1]. So, perform a check here, and handle the
pinctrl states. Also restore the break inputs upon resume, as registers
content may be lost when going to low power mode.

[1] https://lkml.org/lkml/2019/2/5/770

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Split breakinput apply routine to ease PM support

Split breakinput routine that configures STM32 timers 'break' safety
feature upon probe, into two routines:
- stm32_pwm_apply_breakinputs() sets all the break inputs into registers.
- stm32_pwm_probe_breakinputs() probes the device tree break input settings
before calling stm32_pwm_apply_breakinputs()

This is a precursor patch to ease PM support. Registers content may get
lost during low power. So, break input settings applied upon probe need
to be restored upon resume (e.g. by calling stm32_pwm_apply_breakinputs()).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Ensure pwm_apply_state() doesn't modify the state argument

It is surprising for a PWM consumer when the variable holding the
requested state is modified by pwm_apply_state(). Consider for example a
driver doing:

#define PERIOD 5000000
#define DUTY_LITTLE 10
...
struct pwm_state state = {
.period = PERIOD,
.duty_cycle = DUTY_LITTLE,
.polarity = PWM_POLARITY_NORMAL,
.enabled = true,
};

pwm_apply_state(mypwm, &state);
...
state.duty_cycle = PERIOD / 2;
pwm_apply_state(mypwm, &state);

For sure the second call to pwm_apply_state() should still have
state.period = PERIOD and not something the hardware driver chose for a
reason that doesn't necessarily apply to the second call.

So declare the state argument as a pointer to a const type and adapt all
drivers' .apply callbacks.

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

pwm: stm32: Use 3 cells ->of_xlate()

STM32 Timers support generic 3 cells PWM to encode PWM number, period
and polarity.

Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Fix build warning with CONFIG_DMA_ENGINE disabled

Without dmaengine support, we get a harmless warning about an unused
function:

drivers/pwm/pwm-stm32.c:166:12: error: 'stm32_pwm_capture' defined but not used [-Werror=unused-function]

Changing the #ifdef to an IS_ENABLED() check shuts up that warning and
is slightly nicer to read.

Fixes: 53e38fe73f94 ("pwm: stm32: Add capture support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Initialize raw local variables

This removes build warning when COMPILE_TEST=y and MFD_STM32_TIMERS=n
in drivers/pwm/pwm-stm32.c. In function 'stm32_pwm_capture' 'raw_prd' and
'raw_dty' may be used uninitialized in this function
[-Wmaybe-uninitialized]

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: stm32: Use input prescaler to improve period capture

Using input prescaler, capture unit will trigger DMA once every
configurable /2, /4 or /8 events (rising edge). This helps improve
period (only) capture accuracy at high rates.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: stm32: Improve capture by tuning counter prescaler

Currently, capture is based on timeout window to configure prescaler.
PWM capture framework provides 1s window at the time of writing.

There's place for improvement, after input signal has been captured once:
- Finer tune counter clock prescaler, by using 1st capture result (with
arbitrary margin).
- Do a 2nd capture, with scaled capture window.
This increases accuracy, especially at high rates.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: stm32: Add capture support

Add support for PMW input mode on pwm-stm32. STM32 timers support
period and duty cycle capture as long as they have at least two PWM
channels. One capture channel is used for period (rising-edge), one
for duty-cycle (falling-edge).
When there's only one channel available, only period can be captured.
Duty-cycle is simply zero'ed in such a case.

Capture requires exclusive access (e.g. no pwm output running at the
same time, to protect common prescaler).
Timer DMA burst mode (from MFD core) is being used, to take two
snapshots of capture registers (upon each period rising edge).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: stm32: Protect common prescaler for all channels

There may be a race, when configuring two PWM channels, with different
prescaler values, when there's no active channel yet.
Add mutex lock to avoid concurrent access on PWM apply state.
This is also precursor patch for PWM capture support.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Remove unused struct device

dev is never assigned or used. Remove it.

Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: stm32: Adopt SPDX identifier

Add SPDX identifier to make it easier to determine the license of the
file.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add driver for STM32 plaftorm

This driver adds support for PWM driver on STM32 platform.
The SoC have multiple instances of the hardware IP and each
of them could have small differences: number of channels,
complementary output, auto reload register size...

version 9:
- fix commit message header
- remove one space MODULE_ALIAS

version 8:
- fix comments done by Thierry on version 7

version 6:
- change st,breakinput parameter to make it usuable for stm32f7 too.

version 4:
- detect at probe time hardware capabilities
- fix comments done on v2 and v3
- use PWM atomic ops

version 2:
- only keep one comptatible
- use DT parameters to discover hardware block configuration

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>