linux-stable.git/drivers/pwm, branch v4.1

pwm: img: Impose upper and lower timebase steps value

2015-05-19T14:07:40+00:00

The PWM hardware on Pistachio platform has a maximum timebase steps
value to 255. To fix it, let's introduce a compatible-specific
data structure to contain the SoC-specific details and use it to
specify a maximum timebase.

Also, let's limit the minimum timebase to 16 steps, to allow a sane
range of duty cycle steps.

Fixes: 277bb6a29e00 ("pwm: Imagination Technologies PWM DAC driver")
Signed-off-by: Naidu Tellapati 
Signed-off-by: Ezequiel Garcia 
Signed-off-by: Thierry Reding

pwm: Remove __init initializer for pwm_add_table()

2015-04-23T12:50:52+00:00

For platforms that don't support DT, some early MFD modules can register
lookup tables. Remove the __init annotation so that this works. This is
similar to gpio_add_lookup_table() which allows late additions.

CC: Samuel Ortiz 
Cc: Linus Walleij 
Cc: Alexandre Courbot 
Cc: Thierry Reding 
Signed-off-by: Shobhit Kumar 
Signed-off-by: Thierry Reding

pwm: samsung: Fix output race on disabling

2015-03-27T12:06:47+00:00

When disabling the Samsung PWM the output state remains at the level it
was at the end of a PWM cycle. In other words, calling pwm_disable()
when at 100% duty cycle will keep the output active, while at all other
settings the output will go/stay inactive. On top of that the Samsung
PWM settings are double-buffered, which means the new settings only get
applied at the start of a new PWM cycle.

This results in a race if the PWM is at 100% duty cycle and a driver
calls:

  pwm_config(pwm, 0, period);
  pwm_disable(pwm);

In this case the PWMs output will unexpectedly stay active, unless a new
PWM cycle happened to start between the register writes in pwm_config()
and pwm_disable(). As far as I can tell this is a regression introduced
by 3bdf878, before that a call to pwm_config() would call
pwm_samsung_enable() which, while heavy-handed, made sure the expected
settings were live.

To resolve this, while not re-introducing the issues 3bdf878 (flickering
as the PWM got reset while in a PWM cycle) fixed, only force an update
of the settings when at 100% duty cycle, which shouldn't have any
noticeable effect on the output but is enough to ensure the behaviour is
as expected on disable.

Signed-off-by: Sjoerd Simons 
Reviewed-by: Javier Martinez Canillas 
Acked-by: Lukasz Majewski 
Signed-off-by: Thierry Reding

pwm: mxs: Fix period divider computation

2015-03-11T12:11:16+00:00

The driver computes which clock divider it sould be using from the
requested period. This computation assumes that the link between the
register value and the actual divider value is raising 2 to the power of
the registry value.

    div = 1 << regvalue

This is true only for the first 5 values out of 8. Next values are 64,
256 and, 1024 - instead of 32, 64, 128.
This affects only the users requesting a period > 0.04369s.

Replace the computation with a look-up table.

Signed-off-by: Gaetan Hug 
Acked-by: Shawn Guo 
Signed-off-by: Thierry Reding

pwm: atmel-hlcdc: Add errata handling for sama5d4

2015-03-11T10:59:54+00:00

sama5d4 SoC also has an errata on the HLCDC PWM. It is the same as the
sama5d3 that is forbidding the use of div1 prescaler.

Signed-off-by: Nicolas Ferre 
Acked-by: Boris Brezillon 
Signed-off-by: Thierry Reding

pwm: pca9685: Constify struct regmap_config

2015-03-11T09:25:13+00:00

The regmap_config struct may be const because it is not modified by the
driver and regmap_init() accepts pointer to const.

Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Thierry Reding

pwm: tegra: Use NSEC_PER_SEC

2015-02-18T07:40:29+00:00

Instead of using the literal value for the number of nanoseconds per
second, use the macro instead to increase readability.

Signed-off-by: Thierry Reding

pwm: Remove unnecessary check before of_node_put()

2015-02-03T11:56:54+00:00

The of_node_put() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Thierry Reding

pwm: Imagination Technologies PWM DAC driver

2015-01-30T11:16:04+00:00

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 
Signed-off-by: Naidu Tellapati 
Signed-off-by: Sai Masarapu 
Signed-off-by: Ezequiel Garcia 
Reviewed-by: Vladimir Zapolskiy 
[thierry.reding: fixup license header as discussed on list]
Signed-off-by: Thierry Reding

pwm: sti: Maintain a bitmap of configured devices

2015-01-30T11:16:03+00:00

This patch introduces a bitmap which is used to keep track of the
pwm channels which have been configured in a pwm chip.

The method used earlier to find the number of configured channels,
was to count the pwmdevices with PWMF_REQUESTED field set
and period value configured. This was not correct and failed
when of_pwm_get()/pwm_get() and then pwm_config() was used.

Signed-off-by: Ajit Pal Singh 
Signed-off-by: Thierry Reding