Enhanced high resolution PWM module (EHRPWM) hardware can be used to
generate PWM output over 2 channels. This commit adds PWM driver support
for EHRPWM device present on AM33XX SOC. Current implementation supports
simple PWM functionality.
Reviewed-by: NVaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: NPhilip, Avinash <avinashphilip@ti.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

ECAP hardware on AM33XX SOC supports auxiliary PWM (APWM) feature. This
commit adds PWM driver support for ECAP hardware on AM33XX SOC.

In the ECAP hardware, each PWM pin can also be configured to be in
capture mode. Current implementation only supports PWM mode of
operation. Also, hardware supports sync between multiple PWM pins but
the driver supports simple independent PWM functionality.
Reviewed-by: NVaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: NPhilip, Avinash <avinashphilip@ti.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Some versions of GCC don't seem no notice that the initialization of the
index variable is tied to that of the chip variable and falsely report
it as potentially being used uninitialized. However, to save anybody
else from tripping over this, we now initialize the index variable
unconditionally.
Originally-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Add lpc32xx SOC PWM driver.
Signed-off-by: NAlexandre Pereira da Silva <aletes.xgr@gmail.com>
Acked-by: NRoland Stigge <stigge@antcom.de>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Replace printk with pr_* functions to avoid checkpatch warnings.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Also return proper error in tegra_pwm_remove() if pwmchip_remove()
fails.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Acked-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

If the pwmchip_remove() call fails, propagate the error to the driver's
remove callback. This is required to prevent the module from being
unloaded if a PWM provided by the driver is still in use.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

In order to avoid duplicate symbols with legacy PWM API implementations,
the new PWM framework needs to conflict with any of the existing legacy
implementations. This is done in two ways: for implementations provided
by drivers, a conflict is added to the driver to ensure it will have to
be ported to the PWM subsystem before it can coexist with other PWM
providers. For architecture-specific code, the conflict is added to the
PWM symbol to avoid confusion when a previously picked platform or
machine can no longer be selected because of the PWM subsystem being
included.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Call pinctrl subsystem to set up pwm pin.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Use devm_* managed functions to have a clean fail-out.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Use global reset function stmp_reset_block instead of mxs_reset_block
to remove <mach/common.h> inclusion.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Encode soc name in the compatible string to know the specific version
hardware block.  This is the general approach adopted for most bindings.
Change mxs-pwm binding to use the approach.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Add generic PWM framework driver (DT only) for Freescale MXS.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Move the driver to drivers/pwm/ and convert it to use the framework.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Move the driver to drivers/pwm/ and convert it to use the framework.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
[eric@eukrea.com: fix pwmchip_add return code test]
Signed-off-by: NEric Bénard <eric@eukrea.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Move the driver to drivers/pwm/ and convert it to use the framework.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
[eric@eukrea.com: set chip.dev to prevent probe failure]
[eric@eukrea.com: fix pwmchip_add return code test]
Signed-off-by: NEric Bénard <eric@eukrea.com>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This commit moves the PXA PWM driver to the drivers/pwm subdirectory and
converts it to use the new PWM framework.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This commit moves the Blackfin PWM driver to the drivers/pwm sub-
directory and converts it to register with the new PWM framework.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

Add auxdata to instantiate the PWFM controller from a device tree,
include the corresponding nodes in the dtsi files for Tegra 20 and
Tegra 30 and add binding documentation.
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>

This commit adds a generic PWM framework driver for the PWFM controller
found on NVIDIA Tegra SoCs. The driver is based on code from the
Chromium kernel tree and was originally written by Gary King (NVIDIA)
and later modified by Simon Que (Chromium).
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
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>