The WFHWSIZE constant defines the maximum size for the hardware-specific
waveform representation buffer. It is currently local to
drivers/pwm/core.c, which makes it inaccessible to external tools like
bindgen.

Move the constant to include/linux/pwm.h to make it part of the public
API. As part of this change, rename it to PWM_WFHWSIZE to follow
standard kernel conventions for namespacing macros in public headers.

This allows bindgen to automatically generate a corresponding constant
for the Rust PWM abstractions, ensuring the value remains synchronized
between the C core and Rust code and preventing future maintenance
issues.

Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
Link: https://lore.kernel.org/r/20250702-rust-next-pwm-working-fan-for-sending-v7-1-67ef39ff1d29@samsung.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

With this change each pwmchip defining the new-style waveform callbacks
can be accessed from userspace via a character device. Compared to the
sysfs-API this is faster and allows to pass the whole configuration in a
single ioctl allowing atomic application and thus reducing glitches.

On an STM32MP13 I see:

	root@DistroKit:~ time pwmtestperf
	real	0m 1.27s
	user	0m 0.02s
	sys	0m 1.21s
	root@DistroKit:~ rm /dev/pwmchip0
	root@DistroKit:~ time pwmtestperf
	real	0m 3.61s
	user	0m 0.27s
	sys	0m 3.26s

pwmtestperf does essentially:

	for i in 0 .. 50000:
		pwm_set_waveform(duty_length_ns=i, period_length_ns=50000, duty_offset_ns=0)

and in the presence of /dev/pwmchip0 is uses the ioctls introduced here,
without that device it uses /sys/class/pwm/pwmchip0.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/ad4a4e49ae3f8ea81e23cac1ac12b338c3bf5c5b.1746010245.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Add Return and (where interesting) Context sections, fix some formatting
and drop documenting the internal function __pwm_apply().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250417181611.2693599-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

dev_get_drvdata()'s parameter is a const pointer, so the chip passed to
pwmchip_get_drvdata() can be const, too.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250403151134.266388-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Preparing CONFIG_PWM becoming tristate the right magic to check for the
availability of the pwm functions is using IS_REACHABLE() and not
IS_ENABLED(). The latter gives the wrong result for built-in code with
CONFIG_PWM=m.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250217102504.687916-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

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>