The IS31FL32xx family of LED controllers are I2C devices with multiple
constant-current channels, each with independent 256-level PWM control.

Datasheets: http://www.issi.com/US/product-analog-fxled-driver.shtml

This has been tested on the IS31FL3236 and IS31FL3216, on an ARM
(TI am335x) platform.

The programming paradigm of these devices is similar in the following
ways:
 - All registers are 8 bit
 - All LED control registers are write-only
 - Each LED channel has a PWM register (0-255)
 - PWM register writes are shadowed until an Update register is poked
 - All have a concept of Software Shutdown, which disables output

However, there are some differences in devices:
 - 3236/3235 have a separate Control register for each LED,
   (3218/3216 pack the enable bits into fewer registers)
 - 3236/3235 have a per-channel current divisor setting
 - 3236/3235 have a Global Control register that can turn off all LEDs
 - 3216 is unique in a number of ways
    - OUT9-OUT16 can be configured as GPIOs instead of LED controls
    - LEDs can be programmed with an 8-frame animation, with
      programmable delay between frames
    - LEDs can be modulated by an input audio signal
    - Max output current can be adjusted from 1/4 to 2x globally
    - Has a Configuration register instead of a Shutdown register

This driver currently only supports the base PWM control function
of these devices. The following features of these devices are not
implemented, although it should be possible to add them in the future:
 - All devices are capable of going into a lower-power "software
   shutdown" mode.
 - The is31fl3236 and is31fl3235 can reduce the max output current
   per-channel with a divisor of 1, 2, 3, or 4.
 - The is31fl3216 can use some LED channels as GPIOs instead.
 - The is31fl3216 can animate LEDs in hardware.
 - The is31fl3216 can modulate LEDs according to an audio input.
 - The is31fl3216 can reduce/increase max output current globally.

Signed-off-by: David Rivshin <drivshin@allworx.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

Fixes the following randconfig problem

leds-sead3.c:(.text+0x7dc): undefined reference to `led_classdev_unregister'
leds-sead3.c:(.text+0x7e8): undefined reference to `led_classdev_unregister'

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Bryan Wu <cooloney@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-leds@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

Pull backlight updates from Lee Jones:
 - Stop using LP855X Platform Data to control regulators
 - Move PWM8941 WLED driver into Backlight
 - Remove invalid use of IS_ERR_VALUE() macro
 - Remove duplicate check for NULL data before unregistering
 - Export I2C Device ID structure

* tag 'backlight-for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: tosa: Export I2C module alias information
  backlight: lp8788_bl: Delete a check before backlight_device_unregister()
  backlight: sky81452: Remove unneeded use of IS_ERR_VALUE() macro
  backlight: pm8941-wled: Move PM8941 WLED driver to backlight
  backlight: lp855x: Use private data for regulator control

The Qualcomm PM8941 WLED block is used for backlight and should therefor
be in the backlight framework and not in the LED framework. This moves
the driver and adapts to the backlight api instead.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Tested-by: Rob Clark <robdclark@gmail.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

This patch implements LED driver for PowerNV platform using the existing
generic LED class framework.

PowerNV platform has below type of LEDs:
  - System attention
      Indicates there is a problem with the system that needs attention.
  - Identify
      Helps the user locate/identify a particular FRU or resource in the
      system.
  - Fault
      Indicates there is a problem with the FRU or resource at the
      location with which the indicator is associated.

We register classdev structures for all individual LEDs detected on the
system through LED specific device tree nodes. Device tree nodes specify
what all kind of LEDs present on the same location code. It registers
LED classdev structure for each of them.

All the system LEDs can be found in the same regular path /sys/class/leds/.
We don't use LED colors. We use LED node and led-types property to form
LED classdev. Our LEDs have names in this format.

        <location_code>:<attention|identify|fault>

Any positive brightness value would turn on the LED and a zero value would
turn off the LED. The driver will return LED_FULL (255) for any turned on
LED and LED_OFF (0) for any turned off LED.

The platform level implementation of LED get and set state has been
achieved through OPAL calls. These calls are made available for the
driver by exporting from architecture specific codes.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Tested-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This adds support for the LED controller on Broadcom's BCM6358.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

This patch adds a driver to support the ktd2692 flash LEDs.
ktd2692 can control flash current by ExpressWire interface.

Signed-off-by: Ingi Kim <ingi2.kim@samsung.com>
Acked-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

This adds support for the LED controller on Broadcom's BCM6328.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

This patch adds a driver for the 1.5A Step-Up Current Regulator
for Flash LEDs. The device is programmed through a Skyworks proprietary
AS2Cwire serial digital interface.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

This patch adds led-flash support to Maxim max77693 chipset.
A device can be exposed to user space through LED subsystem
sysfs interface. Device supports up to two leds which can
work in flash and torch mode. The leds can be triggered
externally or by software.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>