The pwm_enable() function didn't clear the enabled bit if a call to the
driver's ->enable() callback returned an error. The result was that the
state of the PWM core was wrong. Clearing the bit when enable returns
an error ensures the state is properly set.
Tested-by: NJonathan Richardson <jonathar@broadcom.com>
Reviewed-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NJonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: add missing kerneldoc for the lock]
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Clean up kerneldoc in preparation for including the PWM documentation in
DocBook.
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Remove useless tabs used for padding in structure definitions as well as
some blank lines.
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Some drivers are directly accessing the ->polarity field in pwm_device.
Add a helper to retrieve the current polarity so that we can easily move
this field elsewhere (required to support atomic update).
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

The PWM argument is not modified in PWM property accessors, make it a
const argument so that the accessors can be used from sysfs.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

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

Add a new function to register a PWM chip with channels that have their
initial polarity as specified by an additional parameter. This benefits
drivers of controllers that by default operate with inversed polarity
by removing the need to modify the polarity during initialization.
Signed-off-by: NTim Kryger <tim.kryger@gmail.com>
Signed-off-by: NJonathan Richardson <jonathar@broadcom.com>
[thierry.reding@gmail.com: export pwmchip_add_with_polarity()]
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

In case some drivers are unloading, they can remove lookup tables which
they had registered during their load time to avoid redundant entries if
loaded again.

CC: Samuel Ortiz <sameo@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: NShobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Now that PWM_LOOKUP is not used anymore, modify it to initialize all the
members of struct pwm_lookup.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Add period and polarity members to struct pwm_lookup so that platforms
using the lookup table can be treated the same way as those using the
device tree.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Before we had the PWM framework we used to have a barebone PWM api. The
HAVE_PWM Kconfig symbol used to be selected by the PWM drivers to specify
the PWM API is present in the kernel. Since the last legacy driver is gone
the HAVE_PWM symbol can go aswell.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-pwm@vger.kernel.orig
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

Add a simple sysfs interface to the generic PWM framework.

  /sys/class/pwm/
  `-- pwmchipN/           for each PWM chip
      |-- export          (w/o) ask the kernel to export a PWM channel
      |-- npwm            (r/o) number of PWM channels in this PWM chip
      |-- pwmX/           for each exported PWM channel
      |   |-- duty_cycle  (r/w) duty cycle (in nanoseconds)
      |   |-- enable      (r/w) enable/disable PWM
      |   |-- period      (r/w) period (in nanoseconds)
      |   `-- polarity    (r/w) polarity of PWM (normal/inversed)
      `-- unexport        (w/o) return a PWM channel to the kernel

Based on work by Lars Poeschel.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Lars Poeschel <poeschel@lemonage.de>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

When booted with DT users can use devm version of of_pwm_get() to benefit
from automatic resource release.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: NThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NBryan Wu <cooloney@gmail.com>

Allow client driver to use of_pwm_get() to get the PWM they need. This
is needed for drivers which handle more than one PWM separately, like
leds-pwm driver, which have:

pwmleds {
	compatible = "pwm-leds";
	kpad {
		label = "omap4::keypad";
		pwms = <&twl_pwm 0 7812500>;
		max-brightness = <127>;
	};

	charging {
		label = "omap4:green:chrg";
		pwms = <&twl_pwmled 0 7812500>;
		max-brightness = <255>;
	};
};

in the dts files.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: NThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NBryan Wu <cooloney@gmail.com>

To synchronize the header file definition and the actual code. In the code
the consumer parameter is named as con_id, change the header file and replace
consumer -> con_id in the parameter list.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Ackedy-by: NThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NBryan Wu <cooloney@gmail.com>

Calls to some external PWM chips can sleep. To help users,
add pwm_can_sleep() API.

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NFlorian Vaussard <florian.vaussard@epfl.ch>
Reviewed-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Add support for encoding PWM properties in bit encoded form with
of_pwm_xlate_with_flags() function support. Platforms require platform
specific PWM properties has to populate in 3rd cell of the pwm-specifier
and PWM driver should also set .of_xlate support with this function.
Currently PWM property polarity encoded in bit position 0 of the third
cell in pwm-specifier.
Signed-off-by: NPhilip, Avinash <avinashphilip@ti.com>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Add dummy implemention of public symbols for compilation-safe inclusion
of include/linux/pwm.h file when CONFIG_PWM is not defined.
Reported-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NTushar Behera <tushar.behera@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Add resource managed variants of pwm_get() and pwm_put() for
convenience. Code is largely inspired by the equivalent devm functions
of the regulator framework.
Signed-off-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Some hardware supports inverting the polarity of the PWM signal. This
commit adds support to the PWM framework to allow users of the PWM API
to configure the polarity. Note that in order to reduce complexity,
changing the polarity of a PWM signal is only allowed while the PWM is
disabled.

A practical example where this can prove useful is to simulate inversion
of the duty cycle. While inversion of polarity and duty cycle are not
exactly the same, the differences for most use-cases are negligible.
Signed-off-by: NPhilip, Avinash <avinashphilip@ti.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This patch adds helpers to support device tree bindings for the generic
PWM API. Device tree binding documentation for PWM controllers is also
provided.
Acked-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

In order to get rid of the global namespace for PWM devices, this commit
provides an alternative method, similar to that of the regulator or
clock frameworks, for registering a static mapping for PWM devices. This
works by providing a table with a provider/consumer map in the board
setup code.

With the new pwm_get() and pwm_put() functions available, usage of
pwm_request() and pwm_free() becomes deprecated.
Reviewed-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This commit adds a debugfs interface that can be used to list the
current internal state of the PWM devices registered with the PWM
framework.
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Many PWM controllers provide access to more than a single PWM output and
may even share some resource among them. Allowing a PWM chip to provide
multiple PWM devices enables better sharing of those resources. As a
side-effect this change allows easy integration with the device tree
where a given PWM can be looked up based on the PWM chip's phandle and a
corresponding index.

This commit modifies the PWM core to support multiple PWMs per struct
pwm_chip. It achieves this in a similar way to how gpiolib works, by
allowing PWM ranges to be requested dynamically (pwm_chip.base == -1) or
starting at a given offset (pwm_chip.base >= 0). A chip specifies how
many PWMs it controls using the npwm member. Each of the functions in
the pwm_ops structure gets an additional argument that specified the PWM
number (it can be converted to a per-chip index by subtracting the
chip's base).

The total maximum number of PWM devices is currently fixed to 1024 while
the data is actually stored in a radix tree, thus saving resources if
not all of them are used.
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: NShawn Guo <shawn.guo@linaro.org>
[eric@eukrea.com: fix error handling in pwmchip_add]
Signed-off-by: NEric Bénard <eric@eukrea.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This patch adds framework support for PWM (pulse width modulation) devices.

The is a barebone PWM API already in the kernel under include/linux/pwm.h,
but it does not allow for multiple drivers as each of them implements the
pwm_*() functions.

There are other PWM framework patches around from Bill Gatliff. Unlike
his framework this one does not change the existing API for PWMs so that
this framework can act as a drop in replacement for the existing API.

Why another framework?

Several people argue that there should not be another framework for PWMs
but they should be integrated into one of the existing frameworks like led
or hwmon. Unlike these frameworks the PWM framework is agnostic to the
purpose of the PWM. In fact, a PWM can drive a LED, but this makes the
LED framework a user of a PWM, like already done in leds-pwm.c. The gpio
framework also is not suitable for PWMs. Every gpio could be turned into
a PWM using timer based toggling, but on the other hand not every PWM hardware
device can be turned into a gpio due to the lack of hardware capabilities.

This patch does not try to improve the PWM API yet, this could be done in
subsequent patches.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Acked-by: NKurt Van Dijck <kurt.van.dijck@eia.be>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NMatthias Kaehlcke <matthias@kaehlcke.net>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: NShawn Guo <shawn.guo@linaro.org>
[thierry.reding@avionic-design.de: fixup typos, kerneldoc comments]
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NMark Vels <mark.vels@team-embedded.nl>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>