Pull pwm fixes from Uwe Kleine-König:
 "Two fixes.

  Conor Dooley found and fixed a problem in the pwm-microchip-core
  driver that existed since the driver's birth in v6.5-rc1. It's about a
  corner case that only happens if two pwm devices of the same chip are
  set to the same long period.

  The other problem is about the new pwm API that currently is only
  supported by two hardware drivers. The fix prevents a NULL pointer
  exception if one of the new functions is called for a pwm device with
  a driver that only provides the old callbacks"

* tag 'pwm/for-6.14-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux:
  pwm: Ensure callbacks exist before calling them
  pwm: microchip-core: fix incorrect comparison with max period

If one of the waveform functions is called for a chip that only supports
.apply(), we want that an error code is returned and not a NULL pointer
exception.

Fixes: 6c5126c6406d ("pwm: Provide new consumer API functions for waveforms")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/20250123172709.391349-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Clean up the existing export namespace code along the same lines of
commit 33def8498fdd ("treewide: Convert macro and uses of __section(foo)
to __section("foo")") and for the same reason, it is not desired for the
namespace argument to be a macro expansion itself.

Scripted using

  git grep -l -e MODULE_IMPORT_NS -e EXPORT_SYMBOL_NS | while read file;
  do
    awk -i inplace '
      /^#define EXPORT_SYMBOL_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /^#define MODULE_IMPORT_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /MODULE_IMPORT_NS/ {
        $0 = gensub(/MODULE_IMPORT_NS\(([^)]*)\)/, "MODULE_IMPORT_NS(\"\\1\")", "g");
      }
      /EXPORT_SYMBOL_NS/ {
        if ($0 ~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+),/) {
  	if ($0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/ &&
  	    $0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(\)/ &&
  	    $0 !~ /^my/) {
  	  getline line;
  	  gsub(/[[:space:]]*\\$/, "");
  	  gsub(/[[:space:]]/, "", line);
  	  $0 = $0 " " line;
  	}

  	$0 = gensub(/(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/,
  		    "\\1(\\2, \"\\3\")", "g");
        }
      }
      { print }' $file;
  done

Requested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://mail.google.com/mail/u/2/#inbox/FMfcgzQXKWgMmjdFwwdsfgxzKpVHWPlc
Acked-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Export the pwm_get_state_hw() function. This is useful in cases where
we want to know what the hardware is actually doing, rather than what
what we requested it should do.

Locking had to be rearranged to ensure that the chip is still
operational before trying to access ops now that this can be called
from outside the pwm core.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20241029-pwm-export-pwm_get_state_hw-v2-1-03ba063a3230@baylibre.com
[ukleinek: Add dummy for !CONFIG_PWM]
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

The callbacks for lowlevel pwm drivers were expanded to handle the new
waveform abstraction. When doing that I missed to expand the kernel doc
description. This is catched up here.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/linux-next/20241001135207.125ca7af@canb.auug.org.au
Fixes: 17e40c25158f ("pwm: New abstraction for PWM waveforms")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20241001085138.1025818-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Provide API functions for consumers to work with waveforms.

Note that one relevant difference between pwm_get_state() and
pwm_get_waveform*() is that the latter yields the actually configured
hardware state, while the former yields the last state passed to
pwm_apply*() and so doesn't account for hardware specific rounding.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/6c97d27682853f603e18e9196043886dd671845d.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Up to now the configuration of a PWM setting is described exclusively by
a struct pwm_state which contains information about period, duty_cycle,
polarity and if the PWM is enabled. (There is another member usage_power
which doesn't completely fit into pwm_state, I ignore it here for
simplicity.)

Instead of a polarity the new abstraction has a member duty_offset_ns
that defines when the rising edge happens after the period start. This
is more general, as with a pwm_state the rising edge can only happen at
the period's start or such that the falling edge is at the end of the
period (i.e. duty_offset_ns == 0 or duty_offset_ns == period_length_ns -
duty_length_ns).

A disabled PWM is modeled by .period_length_ns = 0. In my eyes this is a
nice usage of that otherwise unusable setting, as it doesn't define
anything about the future which matches the fact that consumers should
consider the state of the output as undefined and it's just there to say
"No further requirements about the output, you can save some power.".

Further I renamed period and duty_cycle to period_length_ns and
duty_length_ns. In the past there was confusion from time to time about
duty_cycle being measured in nanoseconds because people expected a
percentage of period instead. With "length_ns" as suffix the semantic
should be more obvious to people unfamiliar with the pwm subsystem.
period is renamed to period_length_ns for consistency.

The API for consumers doesn't change yet, but lowlevel drivers can
implement callbacks that work with pwm_waveforms instead of pwm_states.
A new thing about these callbacks is that the calculation of hardware
settings needed to implement a certain waveform is separated from
actually writing these settings. The motivation for that is that this
allows a consumer to query the hardware capabilities without actually
modifying the hardware state.

The rounding rules that are expected to be implemented in the
round_waveform_tohw() are: First pick the biggest possible period not
bigger than wf->period_length_ns. For that period pick the biggest
possible duty setting not bigger than wf->duty_length_ns. Third pick the
biggest possible offset not bigger than wf->duty_offset_ns. If the
requested period is too small for the hardware, it's expected that a
setting with the minimal period and duty_length_ns = duty_offset_ns = 0
is returned and this fact is signaled by a return value of 1.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/df0faa33bf9e7c9e2e5eab8d31bbf61e861bd401.1726819463.git.u.kleine-koenig@baylibre.com
[ukleinek: Update pwm_check_rounding() to return bool instead of int.]
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

This ensures that a pwm_chip that has no corresponding driver isn't used
and that a driver doesn't go away while a callback is still running.

In the presence of device links this isn't necessary yet (so this is no
fix) but for pwm character device support this is needed.

To not serialize all pwm_apply_state() calls, this introduces a per chip
lock. An additional complication is that for atomic chips a mutex cannot
be used (as pwm_apply_atomic() must not sleep) and a spinlock cannot be
held while calling an operation for a sleeping chip. So depending on the
chip being atomic or not a spinlock or a mutex is used.

An additional change implemented here is that on driver remove the
.free() callback is called for each requested pwm_device. This is the
right time because later (e.g. when the consumer calls pwm_put()) the
free function is (maybe) not available any more.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/026aa891c8270a11723a1ba7e4256f456f7e1e86.1726819463.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

There is only a single caller of this function, and that's in
drivers/pwm/core.c itself. So don't export the function.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20240712171821.1470833-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

This function is not supposed to be used any more since commit
c748a6d77c06 ("pwm: Rename pwm_apply_state() to
pwm_apply_might_sleep()") that is included in v6.8-rc1. Two kernel
releases should be enough for everyone to adapt, so drop the old
function that was introduced as a compatibility stub for the transition.

Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>