pwm: dwc: split pci out of core driver

Moving towards adding non-pci support for the driver, move the pci
parts out of the core into their own module. This is partly due to
the module_driver() code only being allowed once in a module and also
to avoid a number of #ifdef if we build a single file in a system
without pci support.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230907161242.67190-2-ben.dooks@codethink.co.uk
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add Renesas RZ/G2L MTU3a PWM driver

The RZ/G2L Multi-Function Timer Pulse Unit 3 (a.k.a MTU3a) uses
one counter and two match components to configure duty_cycle
and period to generate PWM output waveform.

Add basic support for RZ/G2L MTU3a PWM driver by creating separate
PWM channels for each IOs.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: add microchip soft ip corePWM driver

Add a driver that supports the Microchip FPGA "soft" PWM IP core.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add Apple PWM controller

Adds the Apple PWM controller driver.

Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Acked-by: Sven Peter <sven@svenpeter.dev>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add clock based PWM output driver

Some systems have clocks exposed to external devices. If the clock
controller supports duty-cycle configuration, such clocks can be used as
pwm outputs. In fact PWM and CLK subsystems are interfaced with in a
similar way and an "opposite" driver already exists (clk-pwm). Add a
driver that would enable pwm devices to be used via clk subsystem.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: sunplus-pwm: Add Sunplus SoC SP7021 PWM Driver

Add Sunplus SoC SP7021 PWM Driver

Signed-off-by: Hammer Hsieh <hammerh0314@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add support for Xilinx AXI Timer

This adds PWM support for Xilinx LogiCORE IP AXI soft timers commonly
found on Xilinx FPGAs. At the moment clock control is very basic: we
just enable the clock during probe and pin the frequency. In the future,
someone could add support for disabling the clock when not in use.

Some common code has been specially demarcated. While currently only
used by the PWM driver, it is anticipated that it may be split off in
the future to be used by the timer driver as well.

This driver was written with reference to Xilinx DS764 for v1.03.a [1].

[1] https://www.xilinx.com/support/documentation/ip_documentation/axi_timer/v1_03_a/axi_timer_ds764.pdf

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: visconti: Add Toshiba Visconti SoC PWM support

Add driver for the PWM controller on Toshiba Visconti ARM SoC.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix up a couple of checkpatch warnings]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: ntxec: Add driver for PWM function in Netronix EC

The Netronix EC provides a PWM output which is used for the backlight
on some ebook readers. This patches adds a driver for the PWM output.

The .get_state callback is not implemented, because the PWM state can't
be read back from the hardware.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: Add Raspberry Pi Firmware based PWM bus

Adds support to control the PWM bus available in official Raspberry Pi
PoE HAT. Only RPi's co-processor has access to it, so commands have to
be sent through RPi's firmware mailbox interface.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Remove ZTE ZX driver

The ZTE ZX platform is getting removed, so this driver is no longer
needed.

Cc: Jun Nie <jun.nie@linaro.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add PWM fan controller driver for LGM SoC

Intel Lightning Mountain(LGM) SoC contains a PWM fan controller. This
PWM controller does not have any other consumer, it is a dedicated PWM
controller for fan attached to the system. Add driver for this PWM fan
controller.

Signed-off-by: Rahul Tanwar <rahul.tanwar@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add DesignWare PWM Controller Driver

Introduce driver for Synopsys DesignWare PWM Controller used on Intel
Elkhart Lake.

Initial implementation is done by Felipe Balbi while he was working at
Intel with later changes from Raymond Tan and me.

Co-developed-by: Felipe Balbi (Intel) <balbi@kernel.org>
Signed-off-by: Felipe Balbi (Intel) <balbi@kernel.org>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add PWM driver for Intel Keem Bay

The Intel Keem Bay SoC requires PWM support.
Add the pwm-keembay driver to enable this.

Signed-off-by: Lai, Poey Seng <poey.seng.lai@intel.com>
Co-developed-by: Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Signed-off-by: Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Co-developed-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add support for sl28cpld PWM controller

Add support for the PWM controller of the sl28cpld board management
controller. This is part of a multi-function device driver.

The controller has one PWM channel and can just generate four distinct
frequencies.

Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: remove pwm-puv3 driver

The unicore32 port is removed from the kernel.
There is no point to keep stale PWM driver for this architecture.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>

pwm: Add support for Azoteq IQS620A PWM generator

This patch adds support for the Azoteq IQS620A, capable of generating
a 1-kHz PWM output with duty cycle between ~0.4% and 100% (inclusive).

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

bus/ti-pwmss: move TI PWMSS driver from PWM to bus subsystem

The TI PWMSS driver is a simple bus driver for providing power
power management for the PWM peripherals on TI AM33xx SoCs, namely
eCAP, eHRPWM and eQEP. The eQEP is a counter rather than a PWM, so
it does not make sense to have the bus driver in the PWM subsystem
since the PWMSS is not exclusive to PWM devices.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

pwm: sprd: Add Spreadtrum PWM support

This patch adds the Spreadtrum PWM support, which provides maximum 4
channels.

Signed-off-by: Neo Hou <neo.hou@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: sifive: Add a driver for SiFive SoC PWM

Adds a PWM driver for PWM chip present in SiFive's HiFive Unleashed SoC.

Signed-off-by: Wesley W. Terpstra <wesley@sifive.com>
[Atish: Various fixes and code cleanup]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Yash Shah <yash.shah@sifive.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add i.MX TPM PWM driver support

i.MX7ULP has TPM(Low Power Timer/Pulse Width Modulation Module) inside,
it can support multiple PWM channels, all the channels share same
counter and period setting, but each channel can configure its duty and
polarity independently.

There are several TPM modules in i.MX7ULP, the number of channels in TPM
modules are different, it can be read from each TPM module's PARAM
register.

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

pwm: imx: Split into two drivers

The two PWM implementations called v1 (for i.MX1 and i.MX21) and v2 (for
i.MX27 and later) have nothing in common apart from needing two clocks
named "per" and "ipg" and being integrated in a SoC named i.MX.

So split the file containing the two disjunct drivers into two files and
two complete separate drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix a modular build issue]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: remove pwm-bfin driver

The blackfin architecture is getting removed, so this driver is now
obsolete as well.

Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Aaron Wu <aaron.wu@analog.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

pwm: Add STM32 LPTimer PWM driver

Add support for single PWM channel on Low-Power Timer, that can be
found on some STM32 platforms.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: Add ZTE ZX PWM device driver

It adds PWM device driver for ZTE ZX family SoCs. The PWM controller
supports 4 devices with polarity configuration.

The driver has been tested with pwm-regulator support to scale core
voltage via cpufreq.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add MediaTek PWM support

This patch adds support for the PWM core found on current ARM base SoCs
made by MediaTek. This IP core supports 5 channels and has 2 operational
modes. There is the old mode, which is a classical PWM and the new mode
which allows the user to define bitmasks that get clocked out on the
pins. As the subsystem currently only supports PWM cores with the "old"
mode, we can safely ignore the "new" mode for now.

Signed-off-by: John Crispin <john@phrozen.org>
[thierry.reding@gmail.com: minor cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add driver for STM32 plaftorm

This driver adds support for PWM driver on STM32 platform.
The SoC have multiple instances of the hardware IP and each
of them could have small differences: number of channels,
complementary output, auto reload register size...

version 9:
- fix commit message header
- remove one space MODULE_ALIAS

version 8:
- fix comments done by Thierry on version 7

version 6:
- change st,breakinput parameter to make it usuable for stm32f7 too.

version 4:
- detect at probe time hardware capabilities
- fix comments done on v2 and v3
- use PWM atomic ops

version 2:
- only keep one comptatible
- use DT parameters to discover hardware block configuration

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

pwm: Add PWM driver for HiSilicon BVT SOCs

Add PWM driver for the PWM controller found on HiSilicon BVT SoCs such
as Hi3519V100, Hi3516CV300, etc. The PWM controller is primarily in
charge of controlling the P-Iris lens.

Reviewed-by: Jiancheng Xue <xuejiancheng@hisilicon.com>
Signed-off-by: Jian Yuan <yuanjian12@hisilicon.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add support for Meson PWM Controller

Add support for the PWM controller found in the Amlogic SoCs. This
driver supports the Meson8b and GXBB SoCs.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add ChromeOS EC PWM driver

Use the new ChromeOS EC EC_CMD_PWM_{GET,SET}_DUTY commands to control
one or more PWMs attached to the Embedded Controller. Because the EC
allows us to modify the duty cycle (as a percentage, where U16_MAX is
100%) but not the period, we assign the period a fixed value of
EC_PWM_MAX_DUTY and reject all attempts to change it.

This driver supports only device tree at the moment, because that
provides a very flexible way of describing the relationship between PWMs
and their consumer devices (e.g., backlight). On a non-DT system, we'll
probably want to use the non-GENERIC addressing (i.e., we'll need to
make special device instances that will use EC_PWM_TYPE_KB_LIGHT or
EC_PWM_TYPE_DISPLAY_LIGHT), as well as the relatively inflexible
pwm_lookup infrastructure for matching devices. Defer that work for now.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add a driver for the STMPE PWM

This adds a driver for the PWM block found in chips of the STMPE 24xx
series of multi-purpose I2C expanders. (I think STMPE means ST
Microelectronics Multi-Purpose Expander.) This PWM was designed in
accordance with Nokia specifications and is kind of weird and usually
just switched between max and zero duty cycle. However it is indeed a
PWM so it needs to live in the PWM subsystem.

This PWM is mostly used for white LED backlight.

Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add support for Broadcom iProc PWM controller

Add support for the PWM controller present in Broadcom's iProc family of
SoCs. It has been tested on the Northstar+ bcm958625HR board.

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
[thierry.reding@gmail.com: bunch of coding style fixes, cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add PWM driver for OMAP using dual-mode timers

Adds support for using a OMAP dual-mode timer with PWM capability
as a Linux PWM device. The driver controls the timer by using the
dmtimer API.

Add a platform_data structure for each pwm-omap-dmtimer nodes containing
the dmtimers functions in order to get driver not rely on platform
specific functions.

Cc: Grant Erickson <marathon96@gmail.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Tony Lindgren <tony@atomide.com>
[thierry.reding@gmail.com: coding style bikeshed, fix timer leak]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add MediaTek display PWM driver support

Add display PWM driver support to modify backlight for MT8173 and
MT6595. The PWM has one channel to control the brightness of the
display. When the (high_width / period) is closer to 1, the screen
is brighter; otherwise, it is darker.

Signed-off-by: YH Huang <yh.huang@mediatek.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add Broadcom BCM7038 PWM controller support

Add support for the BCM7038-style PWM controller found in all BCM7xxx STB SoCs.
This controller has a hardcoded 2 channels per controller, and cascades a
variable frequency generator on top of a fixed frequency generator which offers
a range of a 148ns period all the way to ~622ms periods.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add support for R-Car PWM Timer

This patch adds support for R-Car SoCs PWM Timer. The PWM timer of
R-Car H2 has 7 channels. So, we can use the channels if we describe
device tree nodes.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add support for the Berlin PWM controller

Add a PWM controller driver for the Marvell Berlin SoCs. This PWM
controller has 4 channels.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: NXP LPC18xx PWM/SCT driver

This commit adds support for NXP LPC18xx PWM/SCT.

NXP LPC SoCs family, which includes LPC18xx/LPC43xx, provides a State
Configurable Timer (SCT) which can be configured as a Pulse Width
Modulator. Other SoCs in that family may share the same hardware.

The PWM supports a total of 16 channels, but only 15 can be simultaneously
requested. There's only one period, global to all the channels, thus PWM
driver will refuse setting different values to it, unless there's only one
channel requested.

Signed-off-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
[thierry.reding@gmail.com: remove excessive padding of fields]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: crc: Add Crystalcove (CRC) PWM driver

The Crystalcove PMIC provides three PWM signals and this driver exports
one of them on the BYT platform which is used to control backlight for
DSI panel. This is platform device implementation of the drivers/mfd
cell device for CRC PMIC.

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>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

pwm: Imagination Technologies PWM DAC driver

The Pistachio SOC from Imagination Technologies includes a Pulse Width
Modulation DAC which produces 1 to 4 digital bit-outputs which represent
digital waveforms. These PWM outputs are primarily in charge of controlling
backlight LED devices.

Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Sai Masarapu <Sai.Masarapu@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
[thierry.reding: fixup license header as discussed on list]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add Allwinner SoC support

This adds a generic PWM framework driver for the PWM controller
found on Allwinner SoCs.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: add support for atmel-hlcdc-pwm device

The HLCDC IP available in some Atmel SoCs (i.e. at91sam9x5, at91sam9n12
or sama5d3 families for instance) provides a PWM device.

This driver add support for a PWM chip exposing a single PWM device (which
will most likely be used to drive a backlight device).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Anthony Harivel <anthony.harivel@emtrion.de>
Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add BCM2835 PWM driver

Add PWM driver for Broadcom BCM2835 processor (Raspberry Pi)

Signed-off-by: Bart Tanghe <bart.tanghe@thomasmore.be>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: lpss: Properly split driver to parts

The driver consists of core, PCI, and platform parts. It would be better
to split them into separate files.

The platform driver is now called pwm-lpss-platform. Thus, previously
set CONFIG_PWM_LPSS=m is not enough to build it. But we are on the safe
side since it seems no one from outside Intel is using it for now.

While here, move to use macros module_pci_driver() and
module_platform_driver().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
[thierry.reding: change select to depends on PWM_LPSS, cleanup]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: sti: Add new driver for ST's PWM IP

This driver supports all current STi platforms' PWM IPs.

Signed-off-by: Ajit Pal Singh <ajitpal.singh@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[thierry.reding: rename module to pwm-sti, fix build breakage]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: add Rockchip SoC PWM support

This commit adds a driver for the PWM controller found on Rockchip
RK29, RK30 and RK31 SoCs.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: kona: Introduce Kona PWM controller support

Add support for the six-channel Kona PWM controller found on Broadcom
mobile SoCs like bcm281xx.

Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: add support for Intel Low Power Subsystem PWM

Add support for Intel Low Power I/O subsystem PWM controllers found on
Intel BayTrail SoC.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Chew, Kean Ho <kean.ho.chew@intel.com>
Signed-off-by: Chang, Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add CLPS711X PWM support

Add a new driver for the ARM CLPS711X Pulse Width Modulator (PWM) interface.
This CPU contain two 4-bit PWM outputs with constant period, based on CPU
PLL frequency. PWM polarity is determined by hardware by power on reset.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add Freescale FTM PWM driver support

The FTM PWM device can be found on Vybrid VF610 Tower and
Layerscape LS-1 SoCs.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Jingchang Lu <b35083@freescale.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add LP3943 PWM driver

This is the other of the LP3943 MFD driver.
LP3943 can be used as a PWM generator, up to 2 channels.

* Two PWM generators supported

* Supported PWM operations
request, free, config, enable and disable

* Pin assignment
A driver data, 'pin_used' is checked when a PWM is requested.
If the output pin is already assigned, then returns as failure.
If the pin is available, 'pin_used' is set.
When the PWM is not used anymore, then it is cleared.
It is defined as unsigned long type for atomic bit operation APIs,
but only LSB 16bits are used because LP3943 has 16 outputs.

Signed-off-by: Milo Kim <milo.kim@ti.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

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>

pwm: add ep93xx PWM support

Remove the non-standard EP93xx PWM driver in drivers/misc and add
a new driver for the PWM controllers on the EP93xx platform based
on the PWM framework.

These PWM controllers each support 1 PWM channel with programmable
duty cycle, frequency, and polarity inversion.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Remove superseded pwm-samsung-legacy driver

This patch removes the now unused pwm-samsung-legacy driver, which was
replaced by new pwm-samsung driver.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Mark Brown <broonie@linaro.org>
Tested-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add new pwm-samsung driver

This patch introduces new Samsung PWM driver, which is completely
rewritten to be multiplatform- and DeviceTree-aware.

In addition, remaining problems of old driver are fixed, such as:
- proper handling of hardware variants,
- synchronization on SMP systems,
- handling of boundary parameter values,
- hardware sharing with PWM clocksource driver,
- undefined state of PWM output after stopping PWM channel.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Mark Brown <broonie@linaro.org>
Tested-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>

pwm: samsung: Rename to pwm-samsung-legacy

This patch renames the old pwm-samsung driver to pwm-samsung-legacy to
create place for the new, rewritten, DT-aware pwm-samsung driver.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Mark Brown <broonie@linaro.org>
Tested-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add Renesas TPU PWM driver

The Timer Pulse Unit (TPU) is a 4-channels 16-bit timer used to generate
waveforms. This driver exposes PWM functions through the PWM API for
other drivers to use.

The code is loosely based on the leds-renesas-tpu driver by Magnus Damm
and the TPU PWM driver shipped in the Armadillo EVA 800 kernel sources.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Tested-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: Add sysfs interface

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: H 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: Thierry Reding <thierry.reding@gmail.com>

pwm: add pca9685 driver

Add pwm driver for the NXP pca9685 16 channel pwm-led controller.

The driver is really barebones at this stage. E.g. the OE' pin and
therefore the corresponding registers are not supported.
The driver was tested on a HW where this pin is tied to GND.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
[thierry.reding@gmail.com: style and whitespace cleanups]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

pwm: atmel: add Timer Counter Block PWM driver

This patch adds a PWM driver based on Atmel Timer Counter Block. The
Timer Counter Block is used in Waveform generator mode.

A Timer Counter Block provides up to 6 PWM devices grouped by 2:
* group 0 = PWM 0 and 1
* group 1 = PWM 2 and 3
* group 2 = PMW 4 and 5

PWM devices in a given group must be configured with the same period
value. If a PWM device in a group tries to change the period value and
the other device is already configured with a different value an error
will be returned.

This driver requires device tree support. The Timer Counter Block number
used to create a PWM chip is given by the tc-block field in an
"atmel,tcb-pwm" compatible node.

This patch was tested on kizbox board (at91sam9g20 SoC) with pwm-leds.

Signed-off-by: Boris BREZILLON <linux-arm@overkiz.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Remove pwm-twl6030 driver

This driver only supported the Charging indicator LED.
New set of drivers going to provide support for both PWMs and LEDs for twl4030
and twl6030 series of PMICs.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: New driver to support PWM driven LEDs on TWL4030/6030 series of PMICs

The driver supports the following LED outputs as generic PWM driver:
TWL4030 LEDA and LEDB (PWMA and PWMB)
TWL6030 Charging indicator LED (PWM LED)

On TWL6030 when the PWM requested LED is configured to be controlled by SW.
In this case the user can enable/disable and set the duty period freely.
When the PWM has been freed, the LED driver is put back to HW control.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: New driver to support PWMs on TWL4030/6030 series of PMICs

The driver supports the following PWM outputs:
TWL4030 PWM0 and PWM1
TWL6030 PWM1 and PWM2

On TWL4030 the PWM signals are muxed. Upon requesting the PWM the driver
will select the correct mux so the PWM can be used. When the PWM has been
freed the original configuration is going to be restored.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Add TI PWM subsystem driver

In some platforms (like am33xx), PWM sub modules (ECAP, EHRPWM, EQEP)
are integrated to PWM subsystem. These PWM submodules has resources
shared and only one register bit-field is provided to control
module/clock enable/disable, makes it difficult to handle common
resources from independent PWMSS submodule drivers.

So the solution here implemented in this patch is, to create driver for
PWMSS and take the role of parent driver for PWM submodules. PWMSS
parent driver enumerates all the child nodes under PWMSS module. Also
symbol "pwmss_submodule_state_change" exported to enable clock gating
for individual PWMSS submodules, and submodule drivers has to enable
clock gating from their drivers.

As this is only supported during DT boot, the parent/child relationship
is created and populated in DT execution flow. The only required change
is inside DTS file, making EHRPWM & ECAP as a child to PWMSS node.

Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Add SPEAr PWM chip driver support

Add support for PWM chips present on SPEAr platforms. These PWM
chips support 4 channel output with programmable duty cycle and
frequency.

More details on these PWM chips can be obtained from relevant
chapter of reference manual, present at following[1] location.

1. http://www.st.com/internet/mcu/product/251211.jsp

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Vipin Kumar <vipin.kumar@st.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Add Ingenic JZ4740 support

This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>

pwm: Move PUV3 PWM driver to PWM framework

This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Qin Rui <qinrui@mprc.pku.edu.cn>
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>

pwm: Move AB8500 PWM driver to PWM framework

This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arun Murthy <arun.murthy@stericsson.com>

pwm: Move TWL6030 PWM driver to PWM framework

This commit moves the driver to drivers/pwm and converts it to the new
PWM framework. In order for this to work properly, register the PWM as
child of the multi-function TWL6030 device.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

pwm: pwm-tiehrpwm: PWM driver support for EHRPWM

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: Vaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: pwm-tiecap: PWM driver support for ECAP APWM

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: Vaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: add lpc32xx PWM support

Add lpc32xx SOC PWM driver.

Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
Acked-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: add pwm-mxs support

Add generic PWM framework driver (DT only) for Freescale MXS.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

ARM vt8500: Move vt8500 pwm driver to pwm framework

Move the driver to drivers/pwm/ and convert it to use the framework.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

ARM Samsung: Move s3c pwm driver to pwm framework

Move the driver to drivers/pwm/ and convert it to use the framework.

Signed-off-by: Sascha 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: Eric Bénard <eric@eukrea.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

ARM i.MX: Move i.MX pwm driver to pwm framework

Move the driver to drivers/pwm/ and convert it to use the framework.

Signed-off-by: Sascha 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: Eric Bénard <eric@eukrea.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Move PXA PWM driver to PWM framework

This commit moves the PXA PWM driver to the drivers/pwm subdirectory and
converts it to use the new PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Move Blackfin PWM driver to PWM framework

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: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Add NVIDIA Tegra SoC support

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: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

pwm: Add PWM framework support

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: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
[thierry.reding@avionic-design.de: fixup typos, kerneldoc comments]
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>