linux-stable.git/drivers/pwm, branch v4.3.3

Merge tag 'pwm/for-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

2015-09-09T17:55:32+00:00

Pull pwm updates from Thierry Reding:
 "This set of changes introduces the beginnings of a new API that's
  based around the concept of states that can be atomically applied.
  Drivers go to various lengths to implement something similar, which
  indicates that the core should really be providing the necessary
  framework.

  On top of that, there is a bit of cleanup as well as improved
  kerneldoc and integration into the device-drivers DocBook.

  Regarding drivers there is a new one for the NXP LPC18xx family of
  SoCs and a couple of fixes for existing drivers (pca9685, Broadcom
  Kona and Atmel HLCDC)"

* tag 'pwm/for-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  ARM: at91: pwm: atmel-hlcdc: Add at91sam9n12 errata
  pwm: Add NXP LPC18xx PWM/SCT DT binding documentation
  pwm: NXP LPC18xx PWM/SCT driver
  pwm-pca9685: Support changing the output frequency
  pwm-pca9685: Fix several driver bugs
  pwm: kona: Modify settings application sequence
  pwm: pca9685: Drop owner assignment
  pwm: Add to device-drivers documentation
  pwm: Clean up kerneldoc
  pwm: Remove useless whitespace
  pwm: sysfs: Remove unnecessary padding
  pwm: sysfs: Properly convert from enum to string
  pwm: Make use of pwm_get_xxx() helpers where appropriate
  pwm: Add pwm_get_polarity() helper function
  pwm: Constify PWM device where possible
  pwm: Add the pwm_is_enabled() helper

ARM: at91: pwm: atmel-hlcdc: Add at91sam9n12 errata

2015-09-09T13:16:01+00:00

The errata for HLCDC PWM of at91sam9n12 are the same as for at91sam9x5.

Signed-off-by: Josh Wu 
Acked-by: Alexandre Belloni 
Signed-off-by: Thierry Reding

pwm: NXP LPC18xx PWM/SCT driver

2015-09-09T13:00:33+00:00

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 
[thierry.reding@gmail.com: remove excessive padding of fields]
Signed-off-by: Thierry Reding

pwm-pca9685: Support changing the output frequency

2015-08-17T14:35:46+00:00

Previously, period_ns and duty_ns were only used to determine the
ratio of ON and OFF time, the default frequency of 200 Hz was never
changed.
The PCA9685 however is capable of changing the PWM output frequency,
which is expected when changing the period.

This patch configures the prescaler accordingly, using the formula
and notes provided in the PCA9685 datasheet.
Bounds checking for the minimum and maximum frequencies, last updated
in revision v.4 of said datasheet, is also added.

The prescaler is only touched if the period changed, because we have to
put the chip into sleep mode to unlock the prescale register.
If it is changed, the PWM output frequency changes for all outputs,
because there is one prescaler per chip. This is documented in the
PCA9685 datasheet and in the comments.

If the duty cycle is not changed at the same time as the period, then
we restart the PWM output using the duty cycle to period ratio from
before the period change.
When using LEDs for example, previously set brightness levels stay the
same when the frequency changes.

Cc: Thierry Reding 
Cc: Steffen Trumtrar 
Signed-off-by: Clemens Gruber 
Signed-off-by: Thierry Reding

pwm-pca9685: Fix several driver bugs

2015-08-17T14:35:13+00:00

Problems:
- When duty_ns == period_ns, the full OFF bit was not cleared and the
  PWM output of the PCA9685 stayed off.
- When duty_ns == period_ns and the catch-all channel was used, the
  ALL_LED_OFF_L register was not cleared.
- The full ON bit was not cleared when setting the OFF time, therefore
  the exact OFF time was ignored when setting a duty_ns < period_ns

Solution: Clear both OFF registers when setting full ON and clear the
full ON bit when changing the OFF registers.

Cc: Thierry Reding 
Cc: Steffen Trumtrar 
Signed-off-by: Clemens Gruber 
Signed-off-by: Thierry Reding

pwm: kona: Modify settings application sequence

2015-08-17T14:19:41+00:00

Update the driver so that settings are applied in accordance with the
most recent version of the hardware spec.  The revised sequence clears
the trigger bit, waits 400ns, writes settings, sets the trigger bit,
and waits another 400ns.  This corrects an issue where occasionally a
requested change was not properly reflected in the PWM output.

Reviewed-by: Arun Ramamurthy 
Reviewed-by: Scott Branden 
Tested-by: Scott Branden 
Reviewed-by: Tim Kryger 
Signed-off-by: Jonathan Richardson 
Signed-off-by: Thierry Reding

pwm: pca9685: Drop owner assignment

2015-08-17T13:56:01+00:00

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.

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

pwm: Clean up kerneldoc

2015-08-17T13:40:20+00:00

Clean up kerneldoc in preparation for including the PWM documentation in
DocBook.

Signed-off-by: Thierry Reding

pwm: Remove useless whitespace

2015-08-17T13:40:19+00:00

Remove useless tabs used for padding in structure definitions as well as
some blank lines.

Signed-off-by: Thierry Reding

pwm: sysfs: Remove unnecessary padding

2015-07-27T10:03:38+00:00

Padding initializers so that assignment operators align is bound to lead
to inconsistencies or churn. Single spaces around the assignment is just
fine.

Signed-off-by: Thierry Reding