Commit Graph

61 Commits

Author SHA1 Message Date
Arvind Yadav
62cdfe6585 backlight: pwm_bl: Make of_device_ids const
of_device_ids are not supposed to change at runtime. All functions
working with of_device_ids provided by <linux/of.h> work with const
of_device_ids. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2017-08-07 17:04:18 +01:00
Geert Uytterhoeven
892c7788c7 backlight: pwm_bl: Fix GPIO out for unimplemented .get_direction()
Commit 7613c92231 ("backlight: pwm_bl: Move the checks for initial
power state to a separate function") not just moved some code, but made
slight changes in semantics.

If a gpiochip doesn't implement the optional .get_direction() callback,
gpiod_get_direction always returns -EINVAL, which is never equal to
GPIOF_DIR_IN, leading to the GPIO not being configured for output.

To avoid this, invert the test and check for not GPIOF_DIR_OUT instead,
like the original code did.

This restores the display on r8a7740/armadillo.

Fixes: 7613c92231 ("backlight: pwm_bl: Move the checks for initial power state to a separate function")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2017-04-19 19:59:44 +01:00
Peter Ujfalusi
d1b8129457 backlight: pwm_bl: Check the PWM state for initial backlight power state
If the PWM is not enabled the backlight initially should not be enabled
either if we have booted with DT and there is a phandle pointing to the
backlight node.

The patch extends the checks to decide if we should keep the backlight off
initially.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2017-01-04 11:37:38 +00:00
Peter Ujfalusi
7613c92231 backlight: pwm_bl: Move the checks for initial power state to a separate function
Move the checks to select the initial state for the backlight to a new
function and document the checks we are doing.

With the separate function it is going to be easier to fix or improve the
initial power state configuration later and it is easier to read the code.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2017-01-04 11:37:38 +00:00
Maxime Ripard
0c9501f823 backlight: pwm_bl: Handle gpio that can sleep
Some backlight GPIOs might be connected to some i2c based expanders whose
access might sleep.

Since it's not in any critical path, use the cansleep variant of the GPIO
API.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2016-10-06 09:27:26 +01:00
Boris Brezillon
6cb9644db7 backlight: pwm_bl: Use pwm_get_args() where appropriate
The PWM framework has clarified the concept of reference PWM config (the
platform dependent config retrieved from the DT or the PWM lookup table)
and real PWM state.

Use pwm_get_args() when the PWM user wants to retrieve this reference
config and not the current state.

This is part of the rework allowing the PWM framework to support
hardware readout and expose real PWM state even when the PWM has just
been requested (before the user calls pwm_config/enable/disable()).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17 14:45:03 +02:00
Boris BREZILLON
7f044b09b6 backlight: pwm_bl: Remove useless call to pwm_set_period()
The PWM period will be set when calling pwm_config. Remove this useless
call to pwm_set_period(), which might mess up the internal PWM state.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-05-17 14:44:58 +02:00
Vladimir Zapolskiy
60d613d6ae backlight: pwm_bl: Free PWM requested by legacy API on error path
If pwm is requested by legacy pwm_request() and if the following
backlight_device_register() call fails, add pwm_free() clean-up.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2016-01-11 10:45:24 +00:00
Philipp Zabel
8777078015 backlight: pwm_bl: Fix broken PWM backlight for non-dt platforms
Commit ee65ad0e2a9e ("backlight: pwm_bl: Avoid backlight flicker when
probed from DT") tries to dereference the device of_node pointer
unconditionally, causing a NULL pointer dereference on non-dt platforms.
Fix it by replacing the phandle variable with a node variable and
by checking that for NULL before dereferencing it.

Reported-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2016-01-11 06:36:43 +00:00
Philipp Zabel
3698d7e7d2 backlight: pwm_bl: Avoid backlight flicker when probed from DT
If the driver is probed from the device tree, and there is a phandle
property set on it, and the enable GPIO is already configured as output,
and the backlight is currently disabled, keep it disabled.
If all these conditions are met, assume there will be some other driver
that can enable the backlight at the appropriate time.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2016-01-11 05:56:22 +00:00
Vladimir Zapolskiy
dc881123aa backlight: pwm: Reject legacy PWM request for device defined in DT
Platform PWM backlight data provided by board's device tree should be
complete enough to successfully request a pwm device using pwm_get()
API. This change fixes a bug, when an arbitrary (first found) PWM is
connected to a "pwm-backlight" compatible device, when explicit PWM
device reference is not given.

Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
already describes "pwms" as a required property, instead of blind
selection of a potentially wrong PWM reject legacy PWM device
registration request, leave legacy API only for non-dt cases.

Based on initial implementation done by Dmitry Eremin-Solenikov.

Reported-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2015-10-15 12:06:28 +01:00
Linus Torvalds
d59b92f93d == Changes to existing drivers ==
- Supply MODULE_DEVICE_TABLE() to ensure probing
  - Constify struct; da9052_bl
  - Enable compile test; lcd_l4f00242t03, lcd_lms283fg05, backlight_gpio
  - Suspend/resume bugfix; lp855x_bl
  - devm_gpiod_get_optional() API fixup; pwm_bl
  - Error handling fixup; backlight
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Merge tag 'backlight-for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "Changes to existing drivers:

   - supply MODULE_DEVICE_TABLE() to ensure probing
   - constify struct; da9052_bl
   - enable compile test; lcd_l4f00242t03, lcd_lms283fg05, backlight_gpio
   - suspend/resume bugfix; lp855x_bl
   - devm_gpiod_get_optional() API fixup; pwm_bl
   - error handling fixup; backlight"

* tag 'backlight-for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: Change the return type of backlight_update_status() to int
  backlight: pwm_bl: Simplify usage of devm_gpiod_get_optional
  backlight: lp855x: Don't clear level on suspend/blank
  backlight: Allow compile test of GPIO consumers if !GPIOLIB
  video: backlight: da9052: Constify platform_device_id
  gpio-backlight: Discover driver during boot time
2015-06-24 18:57:00 -07:00
Axel Lin
cdaefccefa backlight: pwm_bl: Simplify usage of devm_gpiod_get_optional
Since 39b2bbe3d7 (gpio: add flags argument to gpiod_get*() functions),
the gpiod_get* functions take an additional parameter that allows to
specify direction and initial value for output.
Simplify the usage of devm_gpiod_get_optional accordingly.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2015-06-23 15:47:34 +01:00
Nicolas Ferre
68feaca0b1 backlight: pwm: Handle EPROBE_DEFER while requesting the PWM
When trying to request the PWM device with devm_pwm_get(), the EPROBE_DEFER
flag is not handled properly. It can lead to the PWM not being found.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2015-05-26 08:44:59 +01:00
Vladimir Zapolskiy
edf387b6d1 backlight: pwm: Clean-up pwm requested using legacy API
If PWM device is requested by means of legacy API pwm_request(), its
resources are not freed on module unbind, which may cause an oops on
access, e.g. by reading /sys/kernel/debug/pwm.

Reported-by: Dmitry Eremin-Solenikov <dmitry_eremin@mentor.com>
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-11-10 14:42:18 +00:00
Linus Torvalds
4e0b7fe383 Changes to existing drivers
- Checkpatch fixes
   - Removal of unused code in generic_bl
   - Removal of superfluous .owner attribute
 
 New drivers/supported devices
   - None
 
 (Re-)moved drivers
   - None
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Merge tag 'backlight-for-linus-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight driver updates from Lee Jones:
 "Changes to existing drivers:
   - Checkpatch fixes
   - Removal of unused code in generic_bl
   - Removal of superfluous .owner attribute

  No new or removed drivers/supported devices"

* tag 'backlight-for-linus-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: omap1: add blank line after declarations
  backlight: jornada720: Remove 'else' after a return
  backlight: jornada720: Remove 'else' after a return
  backlight: wm831x_bl: Add blank line after declarations
  backlight: tdo24m: Add blank line after declarations
  backlight: s6e63m0: Remove 'else' after a return
  backlight: pcf50633: Add blank line after declarations
  backlight: lp855x: Add blank line after declarations
  backlight: lms501kf03: Remove 'else' after a return
  backlight: lm3639: Remove unnecessary return statements
  backlight: ld9040: Remove 'else' after a return
  backlight: ili922x: Remove 'else' after a return
  backlight: cr_bllcd: Add blank line after declarations
  backlight: corgi_lcd: Add blank line after declarations
  backlight: ams369fg06: Remove 'else' after a return
  backlight: adp8870: Add blank line after declarations
  backlight: adp8860: Add blank line after declarations
  backlight: adp5520: Add blank line after declarations
  backlight: generic_bl: Remove unused function
  backlight: Remove .owner field for drivers using module_platform_driver
2014-10-11 06:38:33 -04:00
Peter Griffin
6728f2b109 backlight: Remove .owner field for drivers using module_platform_driver
This patch removes the superflous .owner field for drivers which
use the module_platform_driver or platform_driver_register api,
as this is overriden in __platform_driver_register.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-08-28 14:09:48 +01:00
Lothar Waßmann
937222c4dd pwm-backlight: Fix bogus request for GPIO#0 when instantiated from DT
commit 257462dbf3 ("pwm-backlight: switch to gpiod interface")
introduced a regression leading to acquiring a bogus GPIO-0 when
configured from DT without an 'enable-gpios' property.
The driver will happily accept the 0 initialized 'enable_gpio' member
of the struct platform_pwm_backlight_data as valid gpio number, and
request this GPIO as enable pin. In case of multiple driver instances,
the second will fail to register with the error message:
pwm-backlight backlight1.23: failed to request GPIO#0: -16

Fix this by setting enable_gpio in the pdata struct to -EINVAL.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-08-20 13:23:00 +01:00
Alexandre Courbot
ff9c5422d8 backlight: pwm-backlight: Use devm_gpiod_get_optional()
Make use of the new devm_gpiod_get_optional() to simplify the probe
code.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-07-18 08:40:06 +01:00
Andrzej Hajda
a5d8e2e73c backlight: Remove trivial get_brightness implementations
Since backlight core returns props.brightness in case get_brightness
is not implemented trivial implementations are not needed anymore.

Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2014-06-23 13:24:22 +01:00
Alexandre Belloni
16fc3352ea pwm-backlight: retrieve configured PWM period
The PWM core is now able to initialize the PWM period from a lookup
table defined by board files. Use it if available and fallback to the
value supplied in pwm_period_ns.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-21 11:19:45 +02:00
Alexandre Courbot
257462dbf3 pwm-backlight: switch to gpiod interface
Switch to the new gpiod interface, which allows to handle GPIO
properties such as active low transparently and removes a whole bunch of
code.

There are still a couple of users of this driver that rely on passing
the enable GPIO number through platform data, so a fallback mechanism
using a GPIO number is still available to avoid breaking them. It will
be removed once current users have switched to the GPIO lookup tables
provided by the gpiod interface.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-05-07 10:15:31 +02:00
Thierry Reding
5f33b89624 pwm-backlight: Disable backlight on shutdown
When a device is shut down, make sure to disable the backlight. If it
stays lit, it gives the impression that the device hasn't turned off.
Furthermore keeping the backlight on may consume power, which is not
what users expect when they shut down a device.

Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-05-02 13:25:59 +02:00
Fabio Estevam
ca7a97add4 backlight: pwm_bl: Remove error message upon devm_kzalloc() failure
No need to have a specific OOM message, since there is generic MM out of memory
message in place.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-12-17 10:18:25 +01:00
Linus Torvalds
0bde7294e2 pwm: Changes for v3.13-rc1
Mostly bug fixes and clean up. There is a new driver, which is actually
 moving a custom PWM driver from drivers/misc.
 
 The majority of the patches are enhancements to the device tree support
 in the pwm-backlight driver. Backlights can now additionally be powered
 using a regulator and enabled using a GPIO in addition to just the PWM
 input.
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Merge tag 'pwm/for-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm changes from Thierry Reding:
 "Mostly bug fixes and clean up.  There is a new driver, which is
  actually moving a custom PWM driver from drivers/misc.

  The majority of the patches are enhancements to the device tree
  support in the pwm-backlight driver.  Backlights can now additionally
  be powered using a regulator and enabled using a GPIO in addition to
  just the PWM input"

* tag 'pwm/for-3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (30 commits)
  Documentation/pwm: Update supported SoC name for pwm-samsung
  pwm: samsung: Fix kernel warning while unexporting a channel
  MAINTAINERS: Move PWM subsystem tree to kernel.org
  Documentation/pwm: Fix trivial typos
  pwm-backlight: Remove unused variable
  pwm_backlight: avoid short blank screen while doing hibernation
  pwm-backlight: Fix brightness adjustment
  pwm: add ep93xx PWM support
  pwm-backlight: Allow for non-increasing brightness levels
  pwm-backlight: Add power supply support
  pwm-backlight: Use new enable_gpio field
  unicore32: Initialize PWM backlight enable_gpio field
  ARM: shmobile: Initialize PWM backlight enable_gpio field
  ARM: SAMSUNG: Initialize PWM backlight enable_gpio field
  ARM: pxa: Initialize PWM backlight enable_gpio field
  ARM: OMAP: Initialize PWM backlight enable_gpio field
  pwm-backlight: Add optional enable GPIO
  pwm-backlight: Track enable state
  pwm-backlight: Refactor backlight power on/off
  pwm-backlight: Improve readability
  ...
2013-11-16 12:21:40 -08:00
Jingoo Han
c512794cad backlight: use dev_get_platdata()
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.  This is a cosmetic change to
make the code simpler and enhance the readability.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:16 +09:00
Thierry Reding
73d4e2b82b pwm-backlight: Remove unused variable
I forgot to remove this during earlier cleanup patches and only checked
various builds for errors, not warnings.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-10-22 09:37:05 +02:00
Huayi Li
1dea1fd092 pwm_backlight: avoid short blank screen while doing hibernation
Use SIMPLE_DEV_PM_OPS macro will initialize the member "freeze"
and "thaw" of pwm_backlight_pm_ops as below,
	.freeze = suspend_fn,
	.thaw = resume_fn,
then during the process of making hibernation snapshot, screen
will be blank at the moment of freezing, and then light at the
moment of thawing.
this is not the right user experience for suspending to disk.

so this patch drops freeze and thaw callback, make the LCD is
always lighting before the final shutdown.

Signed-off-by: Huayi Li <huayi.li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-10-22 09:26:12 +02:00
Thierry Reding
e4bfeda968 pwm-backlight: Fix brightness adjustment
Split adjustment of the brightness (by changing the PWM duty cycle) from
the power on sequence. This fixes an issue where the brightness can no
longer be updated once the backlight has been enabled.

Reported-by: Marc Dietrich <marvin24@gmx.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-18 10:50:46 +02:00
Mike Dunn
8f43e18e27 pwm-backlight: Allow for non-increasing brightness levels
Currently the driver assumes that the values specified in the
brightness-levels device tree property increase as they are parsed from
left to right.  But boards that invert the signal between the PWM output
and the backlight will need to specify decreasing brightness-levels.
This patch removes the assumption that the last element of the array is
the maximum value, and instead searches the array for the maximum value
and uses that in the duty cycle calculation.

Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-16 09:20:09 +02:00
Thierry Reding
22ceeee16e pwm-backlight: Add power supply support
Backlights require a power supply to work properly. This commit adds a
regulator to power up and power down the backlight.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-16 09:20:09 +02:00
Thierry Reding
8265b2e4e6 pwm-backlight: Use new enable_gpio field
Make use of the new enable_gpio field and allow it to be set from DT as
well. Now that all legacy users of platform data have been converted to
initialize this field to an invalid value, it is safe to use the field
from the driver.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-16 09:20:09 +02:00
Thierry Reding
97c3843711 pwm-backlight: Track enable state
Follow up patches will add support for more complex means of powering
the backlight on and off such as using a regulator. To prevent calls to
the regulator API from becoming unbalanced, keep track of the enabled
state internally.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-16 09:05:57 +02:00
Thierry Reding
62b744a87c pwm-backlight: Refactor backlight power on/off
In preparation for adding an optional regulator and enable GPIO to the
driver, split the power on and power off sequences into separate
functions to reduce code duplication at the multiple call sites.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-16 09:05:56 +02:00
Thierry Reding
668e63c670 pwm-backlight: Improve readability
Add more blank lines to increase readability. While at it, remove a
trailing blank line at the end of the file.

Signed-off-by: Thierry Reding <treding@nvidia.com>
2013-10-16 09:05:56 +02:00
Jingoo Han
c791126b93 pwm_backlight: remove unnecessary ifdefs
When the macro such as SIMPLE_DEV_PM_OPS is used, there is
no need to use '#ifdef CONFIG_PM' to prevent build error. Thus,
this patch removes unnecessary ifdefs.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2013-03-08 08:30:13 +01:00
Linus Torvalds
3eb05225ee pwm: Changes for v3.9-rc1
A new driver has been added to support the PWM mode of the timer counter
 blocks found on Atmel AT91 SoCs. The VT8500 driver now supports changing
 the PWM signal polarity and the TI drivers (EHRPWM and ECAP) gained
 suspend and resume functionality.
 
 User drivers can now query the core for whether access to a PWM device
 will sleep (if the PWM chip is on a slow bus such as I2C or SPI).
 
 The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK state
 in addition to the FB layer's blanking states.
 
 To round things off, a few fixes and cleanups are also included.
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Merge tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm

Pull PWM changes from Thierry Reding:
 "A new driver has been added to support the PWM mode of the timer
  counter blocks found on Atmel AT91 SoCs.  The VT8500 driver now
  supports changing the PWM signal polarity and the TI drivers (EHRPWM
  and ECAP) gained suspend and resume functionality.

  User drivers can now query the core for whether access to a PWM device
  will sleep (if the PWM chip is on a slow bus such as I2C or SPI).

  The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK
  state in addition to the FB layer's blanking states.

  To round things off, a few fixes and cleanups are also included"

* tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm:
  pwm: twl: Use to_twl() instead of container_of()
  pwm: tegra: assume CONFIG_OF
  pwm_backlight: Validate dft_brightness in main probe function
  pwm: Export pwm_{set,get}_chip_data()
  pwm: Make Kconfig entries more consistent
  pwm: Add can_sleep property to drivers
  pwm: Add pwm_can_sleep() as exported API to users
  pwm-backlight: handle BL_CORE_FBBLANK state
  pwm: pwm-tiecap: Low power sleep support
  pwm: pwm-tiehrpwm: Low power sleep support
  pwm: pwm-tiehrpwm: Update the clock handling of pwm-tiehrpwm driver
  pwm: vt8500: Add polarity support
  pwm: vt8500: Register write busy test performed incorrectly
  pwm: atmel: add Timer Counter Block PWM driver
2013-02-26 09:34:29 -08:00
Jingoo Han
e6e3dbf95c pwm_backlight: use bl_get_data instead of dev_get_drvdata
Use the wrapper function for getting the driver data using
backlight_device instead of using dev_get_drvdata with &bd->dev, so we can
directly pass a struct backlight_device.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21 17:22:24 -08:00
Peter Ujfalusi
83cfd72669 pwm_backlight: Validate dft_brightness in main probe function
Move the dft_brightness validity check from the DT parsing function to the
main probe. In this way we can validate it in case we are booting with or
without DT.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2013-01-31 13:47:51 +01:00
Alexandre Courbot
0132267d65 pwm-backlight: handle BL_CORE_FBBLANK state
According to include/linux/backlight.h, the fb_blank field is to be
removed and blank status should preferably be set by setting the
BL_CORE_FBBLANK bit of the state field. This patch ensures this
condition is also taken into account when updating the backlight state.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2013-01-30 08:52:00 +01:00
Sachin Kamat
60ce70285b pwm-backlight: Use devm_pwm_get() instead of pwm_get()
Managed versions of the pwm_get() and pwm_put() functions were recently
added to the PWM framework. They can be used to simplify cleanup in the
error paths and the device removal callback.

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-10-05 20:56:39 +02:00
Alexandre Courbot
9fb978b12f pwm_backlight: pass correct brightness to callback
pwm_backlight_update_status calls the notify() and notify_after()
callbacks before and after applying the new PWM settings. However, if
brightness levels are used, the brightness value will be changed from
the index into the levels array to the PWM duty cycle length before
being passed to notify_after(), which results in inconsistent behavior.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-23 13:24:04 +02:00
Thierry Reding
3e3ed6cdc4 pwm-backlight: Add rudimentary device tree support
This commit adds very basic support for device tree probing. Currently,
only a PWM and a list of distinct brightness levels can be specified.
Enabling or disabling backlight power via GPIOs is not yet supported.

Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-23 13:23:52 +02:00
Julia Lawall
ce969228fd drivers/video/backlight: use devm_ functions
The various devm_ functions allocate memory that is released when a driver
detaches.  This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 16:58:33 -07:00
Mark Brown
e2c17bc6f7 backlight: convert pwm_bl to dev_pm_ops
Should be no functional changes, mainly a reorganisation to support future
work.

[akpm@linux-foundation.org: fix CONFIG_PM=n build]
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:48 -08:00
Axel Lin
81178e0216 backlight: convert drivers/video/backlight/* to use module_platform_driver()
Convert the drivers in drivers/video/backlight/* to use the
module_platform_driver() macro which makes the code smaller and a bit
simpler.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>	[ep93xx_bl.c]
Cc: Mike Rapoport <mike@compulab.co.il>
Cc: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:48 -08:00
Dilan Lee
cc7993f643 backlight: add a callback 'notify_after' for backlight control
We need a callback to do some things after pwm_enable, pwm_disable
and pwm_config.

Signed-off-by: Dilan Lee <dilee@nvidia.com>
Reviewed-by: Robert Morell <rmorell@nvidia.com>
Reviewed-by: Arun Murthy <arun.murthy@stericsson.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-25 16:25:34 -07:00
Robert Morell
ef0a5e80f5 pwm_backlight: add check_fb() hook
In systems with multiple framebuffer devices, one of the devices might be
blanked while another is unblanked.  In order for the backlight blanking
logic to know whether to turn off the backlight for a particular
framebuffer's blanking notification, it needs to be able to check if a
given framebuffer device corresponds to the backlight.

This plumbs the check_fb hook from core backlight through the
pwm_backlight helper to allow platform code to plug in a check_fb hook.

Signed-off-by: Robert Morell <rmorell@nvidia.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Arun Murthy <arun.murthy@stericsson.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:00 -07:00
Matthew Garrett
bb7ca747f8 backlight: add backlight type
There may be multiple ways of controlling the backlight on a given
machine.  Allow drivers to expose the type of interface they are
providing, making it possible for userspace to make appropriate policy
decisions.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:43:59 -07:00
Arun Murthy
fef7764f8b backlight: add low threshold to pwm backlight
The intensity of the backlight can be varied from a range of
max_brightness to zero.  Though most, if not all the pwm based backlight
devices start flickering at lower brightness value.  And also for each
device there exists a brightness value below which the backlight appears
to be turned off though the value is not equal to zero.

If the range of brightness for a device is from zero to max_brightness.  A
graph is plotted for brightness Vs intensity for the pwm based backlight
device has to be a linear graph.

intensity
	  |   /
	  |  /
	  | /
	  |/
	  ---------
	 0	max_brightness

But pratically on measuring the above we note that the intensity of
backlight goes to zero(OFF) when the value in not zero almost nearing to
zero(some x%).  so the graph looks like

intensity
	  |    /
	  |   /
	  |  /
	  |  |
	  ------------
	 0   x	 max_brightness

In order to overcome this drawback knowing this x% i.e nothing but the low
threshold beyond which the backlight is off and will have no effect, the
brightness value is being offset by the low threshold value(retaining the
linearity of the graph).  Now the graph becomes

intensity
	  |     /
	  |    /
	  |   /
	  |  /
	  -------------
	   0	  max_brightness

With this for each and every digit increment in the brightness from zero
there is a change in the intensity of backlight.  Devices having this
behaviour can set the low threshold brightness(lth_brightness) and pass
the same as platform data else can have it as zero.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Arun Murthy <arun.murthy@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-12 07:55:33 -08:00