linux-toradex.git/include/linux/pwm.h, branch v4.9.16

pwm: Unexport children before chip removal

2016-09-05T14:45:39+00:00

Exported pwm channels aren't removed before the pwmchip and are
leaked. This results in invalid sysfs files. This fix removes
all exported pwm channels before chip removal.

Signed-off-by: David Hsu 
Fixes: 76abbdde2d95 ("pwm: Add sysfs interface")
Signed-off-by: Thierry Reding

Merge branch 'for-4.8/capture' into for-next

2016-07-25T14:23:39+00:00

Merge branch 'for-4.8/core' into for-next

2016-07-25T14:23:37+00:00

pwm: Remove gratuitous blank line

2016-07-08T16:11:51+00:00

Commit 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic
updates") introduced this double blank line by mistake.

Signed-off-by: Thierry Reding

pwm: Add relative duty cycle manipulation helpers

2016-07-08T15:52:19+00:00

The PWM framework expects PWM users to configure the duty cycle in nano-
seconds, but many users want to express the duty cycle relatively to the
period value (i.e. duty_cycle = 33% of the period).

Add the pwm_{get,set}_relative_duty_cycle() helpers to ease this kind of
conversion.

Signed-off-by: Boris Brezillon 
Tested-by: Heiko Stuebner 
Signed-off-by: Thierry Reding

pwm: Add a helper to prepare a new PWM state

2016-07-08T15:52:18+00:00

The pwm_init_state() helper prepares a new state object containing the
current PWM state except for the polarity and period fields which are
set to the reference values (those in struct pwm_args).

This is particularly useful for PWM users who want to apply a new duty-
cycle expressed relatively to the reference period without changing the
enable state.

Signed-off-by: Boris Brezillon 
Tested-by: Heiko Stuebner 
Signed-off-by: Thierry Reding

pwm: Fix pwm_apply_args()

2016-06-23T16:37:05+00:00

Commit 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic
updates"), implemented pwm_disable() as a wrapper around
pwm_apply_state(), and then, commit ef2bf4997f7d ("pwm: Improve args
checking in pwm_apply_state()") added missing checks on the ->period
value in pwm_apply_state() to ensure we were not passing inappropriate
values to the ->config() or ->apply() methods.

The conjunction of these 2 commits led to a case where pwm_disable()
was no longer succeeding, thus preventing the polarity setting done
in pwm_apply_args().

Set a valid period in pwm_apply_args() to ensure polarity setting
won't be rejected.

Signed-off-by: Boris Brezillon 
Reported-by: Geert Uytterhoeven 
Suggested-by: Brian Norris 
Fixes: 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates")
Tested-by: Geert Uytterhoeven 
Reviewed-by: Brian Norris 
Signed-off-by: Thierry Reding

pwm: Add PWM capture support

2016-06-10T14:01:35+00:00

Supply a PWM capture callback op in order to pass back information
obtained by running analysis on a PWM signal. This would normally (at
least during testing) be called from the sysfs routines with a view to
printing out PWM capture data which has been encoded into a string.

Signed-off-by: Lee Jones 
[thierry.reding@gmail.com: make capture data unsigned int for symmetry]
Signed-off-by: Thierry Reding

pwm: Improve args checking in pwm_apply_state()

2016-06-10T12:21:00+00:00

It seems like in the process of refactoring pwm_config() to utilize the
newly-introduced pwm_apply_state() API, some args/bounds checking was
dropped.

In particular, I noted that we are now allowing invalid period
selections, e.g.:

  # echo 1 > /sys/class/pwm/pwmchip0/export
  # cat /sys/class/pwm/pwmchip0/pwm1/period
  100
  # echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
  [... driver may or may not reject the value, or trigger some logic bug ...]

It's better to see:

  # echo 1 > /sys/class/pwm/pwmchip0/export
  # cat /sys/class/pwm/pwmchip0/pwm1/period
  100
  # echo 101 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
  -bash: echo: write error: Invalid argument

This patch reintroduces some bounds checks in both pwm_config() (for its
signed parameters; we don't want to convert negative values into large
unsigned values) and in pwm_apply_state() (which fix the above described
behavior, as well as other potential API misuses).

Fixes: 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates")
Signed-off-by: Brian Norris 
Acked-by: Boris Brezillon 
Signed-off-by: Thierry Reding

pwm: Add core infrastructure to allow atomic updates

2016-05-17T12:48:03+00:00

Add an ->apply() method to the pwm_ops struct to allow PWM drivers to
implement atomic updates. This method is preferred over the ->enable(),
->disable() and ->config() methods if available.

Add the pwm_apply_state() function to the PWM user API.

Note that the pwm_apply_state() does not guarantee the atomicity of the
update operation, it all depends on the availability and implementation
of the ->apply() method.

pwm_enable/disable/set_polarity/config() are now implemented as wrappers
around the pwm_apply_state() function.

pwm_adjust_config() is allowing smooth handover between the bootloader
and the kernel. This function tries to adapt the current PWM state to
the PWM arguments coming from a PWM lookup table or a DT definition
without changing the duty_cycle/period proportion.

Signed-off-by: Boris Brezillon 
[thierry.reding@gmail.com: fix a couple of typos]
Signed-off-by: Thierry Reding