pwm: atmel: Make use of devm_pwmchip_alloc() function

This prepares the pwm-atmel 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/f2a83af5660de461b4dcaf76929e9813bddfeff1.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: atmel: 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/f8ca10033204111e4eb2e7a4dad0bd1f7586c735.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: atmel: 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 atmel_pwm_chip. To just not have to
do that, rework atmel_pwm_enable_clk_if_on() to take a pwm_chip.

Link: https://lore.kernel.org/r/c9a92f77760e401debfe0c9bfc086222f31fb3c4.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

pwm: atmel: Don't use pwm consumer API

Lowlevel driver callbacks are not supposed to use the consumer API
functions. Currently this works, but with the upcoming locking changes
this probably results in dead locks.

Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Link: https://lore.kernel.org/r/20240129085627.2386470-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

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: atmel: Remove redundant of_match_ptr()

The driver depends on CONFIG_OF, it is not necessary to use
of_match_ptr() here.

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

pwm: atmel: Simplify using devm functions

For all resources used by the driver there is a devm variant to allocate
these. This simplifies the error path in the probe callback and allows
to drop the remove callback.

While at it also use dev_err_probe() to compact returning an error.

With the remove callback gone, there is no user of driver data left, so
the call to platform_set_drvdata() can also be dropped.

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

pwm: atmel: Enable clk when pwm already enabled in bootloader

The driver would never call clk_enable() if the PWM channel was already
enabled in bootloader which lead to dump the warning message "the PWM
clock already disabled" when turning off the PWM channel.

Add atmel_pwm_enable_clk_if_on() in probe function to enable clock if
the PWM channel was already enabled in bootloader.

Signed-off-by: Guiting Shen <aarongt.shen@gmail.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

docs: update some straggling Documentation/arm references

The Arm documentation has moved to Documentation/arch/arm; update the
last remaining references to match.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Samuel Holland <samuel@sholland.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # for pwm
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

pwm: atmel: 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>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Make .get_state() callback return an error code

.get_state() might fail in some cases. To make it possible that a driver
signals such a failure change the prototype of .get_state() to return an
error code.

This patch was created using coccinelle and the following semantic patch:

@p1@
identifier getstatefunc;
identifier driver;
@@
struct pwm_ops driver = {
...,
.get_state = getstatefunc
,...
};

@p2@
identifier p1.getstatefunc;
identifier chip, pwm, state;
@@
-void
+int
getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state)
{
...
- return;
+ return 0;
...
}

plus the actual change of the prototype in include/linux/pwm.h (plus some
manual fixing of indentions and empty lines).

So for now all drivers return success unconditionally. They are adapted
in the following patches to make the changes easier reviewable.

Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221130152148.2769768-2-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: atmel: Remove redundant initialization of variable timeout

The variable timeout is being initialized with a value that is never
read, it is being re-assigned the same value later on. Remove the
redundant initialization and keep the latter assignment because it's
closer to the use of the variable.

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

pwm: atmel: Drop unused header

Since commit 52eaba4cedbd ("pwm: atmel: Rework tracking updates pending
in hardware") the driver doesn't make use of mutexes any more, so the
header defining these doesn't need to be included.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Rework tracking updates pending in hardware

This improves the driver's behavior in several ways:

- The lock is held for shorter periods and so a channel that is currently
waited for doesn't block disabling another channel.

- It's easier to understand because the procedure is split into more
semantic units and documentation is improved

- A channel is only set to pending when such an event is actually
scheduled in hardware (by writing the CUPD register).

- Also wait in .get_state() to report the last configured state instead
of (maybe) the previous one. This fixes the read back duty cycle and so
prevents a warning being emitted when PWM_DEBUG is on.

Tested on an AriettaG25.

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: atmel: Improve duty cycle calculation in .apply()

In the calculation of the register value determining the duty cycle the
requested period is used instead of the actually implemented period which
results in suboptimal settings.

The following example assumes an input clock of 133333333 Hz on one of
the SoCs with 16 bit period.

When the following state is to be applied:

.period = 414727681
.duty_cycle = 652806

the following register values used to be calculated:

PRES = 10
CPRD = 54000
CDTY = 53916

which yields an actual duty cycle of a bit more than 645120 ns.

The setting

PRES = 10
CPRD = 54000
CDTY = 53915

however yields a duty of 652800 ns which is between the current result
and the requested value and so is a better approximation.

The reason for this error is that for the calculation of CDTY the
requested period was used instead of the actually implemented one.

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

pwm: atmel: Fix duty cycle calculation in .get_state()

The CDTY register contains the number of inactive cycles. .apply() does
this correctly, however .get_state() got this wrong.

Fixes: 651b510a74d4 ("pwm: atmel: Implement .get_state()")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Free resources only after pwmchip_remove()

Before pwmchip_remove() returns the PWM is expected to be functional. So
remove the pwmchip before disabling the clock.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Claudiu Beznea <claudiu.beznea@microchip.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: atmel: Convert to devm_platform_ioremap_resource()

Use devm_platform_ioremap_resource() to simplify code.

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

pwm: atmel: Implement .get_state()

This function reads back the configured parameters from the hardware. As
.apply() rounds down (mostly) I'm rounding up in .get_state() to achieve
that applying a state just read from hardware is a no-op.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Use register accessors for channels

This makes it a bit easier when instrumenting register access to only
have to add code in one place.

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

pwm: atmel: Document known weaknesses of both hardware and software

This documents the my findings while reading through the driver and the
reference manual.

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

pwm: atmel: Replace loop in prescale calculation by ad-hoc calculation

The calculated values are the same with the modified algorithm. The only
difference is that the calculation is a bit more efficient.

Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Use a constant for maximum prescale value

The maximal prescale value is 10 for all supported variants. So drop the
member in the variant description and introduce a global constant
instead.

This reduces the size of the variant descriptions and the .apply()
callback can be compiled a bit more effectively.

Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Add a hint where to find hardware documentation

Most Microchip (formerly Atmel) chips have publicly available manuals.
A comprehensive list is already contained in the documentation folder.
Reference this list in the header of the driver to allow reviewers to
find the relevant manuals.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Consolidate driver data initialization

This helps readability by separating the driver-specific bits from the
PWM framework bits.

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

pwm: atmel: Remove unneeded check for match data

Since the driver is now exclusively DT, it only binds if it finds a
match in the of_device_id table. But in that case the associated data
can never be NULL, so drop the unnecessary check.

While at it, drop the extra local variable and store the pointer to
this per-SoC data in the driver data directly.

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

pwm: atmel: Remove platform_device_id and use only dt bindings

Since commit 26202873bb51 ("avr32: remove support for AVR32
architecture") there is no more user of platform_device_id and we
should only use dt bindings

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 191

Based on 1 normalized pattern(s):

licensed under gplv2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 99 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170027.163048684@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

pwm: atmel: Remove useless symbolic definitions

The values that these symbols define are only assigned to the per-SoC
structure where the context is clear, so there's no need for the extra
symbolic name.

Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Add support for SAM9X60's PWM controller

Add support for SAM9X60's PWM controller.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Rename objects of type atmel_pwm_data

Rename objects of type atmel_pwm_data to contain chip name instead of
version number.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Add support for controllers with 32 bit counters

SAM9X60's PWM controller uses 32 bits counters thus it could generate
signals with higher period and duty cycles than the old ones. Prepare
the current driver to be able to work with old controllers (that uses
16 bits counters) and with the new SAM9X60's controller, by providing
counters information based on compatible string.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Add struct atmel_pwm_data

Add struct atmel_pwm_data to embed different per controller information.
It prepares adding support for another similar controller that needs
additional information. At this stage, embed a member of type struct
atmel_pwm_registers in it.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Enable PWM on sama5d2

sama5d2 can use the same atmel_pwm_data as sama5d3.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Switch to atomic PWM

The currently Atmel PWM controllers supported by this driver could
change period or duty factor without channel disable, for regular
channels (sama5d3 support this by using period or duty factor update
registers, sam9rl support this by writing channel update register and
select the corresponding update: period or duty factor). The chip
doesn't support run time changings of signal polarity. To take advantage
of atomic PWM framework and let controller works without glitches, in
this patch only the duty factor could be changed without disabling PWM
channel. For period and signal polarity the atomic PWM is simulated by
disabling + enabling the right PWM channel.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Remove .can_sleep from struct pwm_chip

All PWM devices have been marked as "might sleep" since v4.5, there is
no longer a need to differentiate on a per-chip basis.

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

pwm: atmel: Use of_device_get_match_data()

Use of_device_get_match_data() instead of an open-coded variant.

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

pwm: atmel: Fix checkpatch warnings

Avoid an overly long line by moving a comment around, and remove a use
of else-after-return.

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

pwm: atmel: Fix disabling of PWM channels

When disabling a PWM channel, the PWM clock was being stopped
immediately after writing to PWM_DIS. As a result, the disabling
of the PWM channel did not complete properly, and the PWM output
might be left at the wrong level.

Fix this by waiting for the channel to be effectively disabled
(by checking the PWM_SR register) before disabling the clock.

Signed-off-by: Guillermo Rodriguez <guille.rodriguez@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Make use of pwm_get_xxx() helpers where appropriate

Use the pwm_get_xxx() helpers instead of directly accessing the fields
in struct pwm_device. This will allow us to smoothly move to the atomic
update approach.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add the pwm_is_enabled() helper

Some PWM drivers are testing the PWMF_ENABLED flag. Create a helper
function to hide the logic behind enabled test. This will allow us to
smoothly move from the current approach to an atomic PWM update
approach.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Fix incorrect CDTY value after disabling

pwm-leds calls .config() and .disable() in a row. This exhibits that it
may happen that the channel gets disabled before CDTY has been updated
with CUPD. The issue gets quite worse with long periods. So, ensure that
at least one period has past before disabling the channel by polling
ISR.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Gaël PORTAY <gael.portay@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Fix incorrect CDTY value after enabling

CUPD is not flushed before enabling the channel so it will update
CDTY/CPRD just after one period. So we always set CUPD, even when the
channel is not enabled.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Fix calculation of prescale value

The prescale value used for calculating the period was incremented
afterwards, thus the resulting prescale value is by one too high.
This resulted in a PWM frequency only half as high as requested.

This patch moves the 64 bit division out of the prescale loop to
correct the above issue and make the calculation more efficient.

Signed-off-by: Nikolaus Voss <n.voss@weinmann-emt.de>
Tested-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: set pwm_chip can_sleep flag

atmel_pwm_config() calls clk_get_rate() which might sleep, so we need to
set pwm_chip can_sleep flag.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: correct CDTY calculation

From the datasheet, the actual duty cycle is:

(period - (1 / clk) * CDTY) / period

This actually correct the polarity of the PWM and solves the issue that
pwm-leds exhibits: when setting a duty cycle of 0 and then disabling a
channel, the level was wrong (1 when the polarity was normal and 0 when
the polarity was inversed).

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: Fix polarity handling

When atmel_pwm_config() calculates and then sets the prescaler, it is
overwriting the channel's CMR register so we are losing the CPOL
configuration.

As atmel_pwm_config() is always called before enabling a channel,
inverting the polarity doesn't work.

Fix that by reading CMR first and only overwriting the prescaler bits.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel-pwm: Do not unprepare clock after successful registration

When the PWM controller is registered successfully, the clock can not
unprepare, so fix it.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel-pwm: Add Atmel PWM controller driver

Add a PWM framework driver for the PWM controller found on Atmel SoCs.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
[thierry.reding: coding style and other minor cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>