linux-toradex.git/Documentation/driver-api/pwm.rst, branch v6.4-rc2

pwm: Delete deprecated functions pwm_request() and pwm_free()

2023-04-13T12:27:53+00:00

Since commit 5a7fbe452ad9 ("backlight: pwm_bl: Drop support for legacy PWM
probing") the last user of pwm_request() and pwm_free() is gone. So remove
these functions that were deprecated over 10 years ago in commit
8138d2ddbcca ("pwm: Add table-based lookup for static mappings").

Signed-off-by: Uwe Kleine-König 
[thierry.reding@gmail.com: clean up a bit after removal]
Signed-off-by: Thierry Reding

pwm: core: Get rid of unused devm_of_pwm_get()

2022-09-19T13:17:05+00:00

The devm_of_pwm_get() has recently lost its single user, drop
the dead API as well.

Note, the new code should use either plain pwm_get() or managed
devm_pwm_get() or devm_fwnode_pwm_get() APIs.

Signed-off-by: Andy Shevchenko 
Acked-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20220826172642.16404-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Guenter Roeck

pwm: Document that the pinstate of a disabled PWM isn't reliable

2022-05-20T14:36:07+00:00

Some (most?) drivers emit the inactive state when the PWM is disabled.
However there are exceptions, so document that a consumer better doesn't
depend on this behaviour.

Some known exceptions:

  - imx27 emits 0 independent of the configured polarity
  - mxs just drives the output to the last emitted state.
  - iqs620a makes the output tristated on disable, so an external
    pull-down would be required.

Signed-off-by: Uwe Kleine-König 
Acked-by: Alexander Stein 
Signed-off-by: Thierry Reding

pwm: core: Remove unused devm_pwm_put()

2021-06-30T17:12:19+00:00

There are no users and seems no will come of the devm_pwm_put().
Remove the function.

While at it, slightly update documentation.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: core: Support new usage_power setting in PWM state

2021-06-04T09:43:52+00:00

If usage_power is set, the PWM driver is only required to maintain
the power output but has more freedom regarding signal form.

If supported, the signal can be optimized, for example to
improve EMI by phase shifting individual channels.

Signed-off-by: Clemens Gruber 
Signed-off-by: Thierry Reding

pwm: Reword docs about pwm_apply_state()

2021-04-26T06:49:48+00:00

The main issue is that the current documentation talks about the
non-existent function pwm_get_last_applied_state. (This was right in the
context of
https://lore.kernel.org/linux-pwm/20210406073036.26857-1-u.kleine-koenig@pengutronix.de/
but was then missed to adapt when this patch was reduced to a
documentation update.)

While at is also clarify "last applied PWM state" to "PWM state that was
passed to the last invocation of pwm_apply_state()" to better
distinguish to the last actually implemented state and reword to drop a
word repetition.

Fixes: 1a7a6e8072ea ("pwm: Clarify which state pwm_get_state() returns")
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

pwm: Clarify which state pwm_get_state() returns

2021-04-09T12:17:03+00:00

Given that lowlevel drivers usually cannot implement exactly what a
consumer requests with pwm_apply_state() there is some rounding
involved.

pwm_get_state() returns the setting that was requested most recently by
the consumer (opposed to what was actually implemented in hardware in
reply to the last request). Clarify this in the function kerneldoc.

Signed-off-by: Uwe Kleine-König 
Signed-off-by: Thierry Reding

docs: driver-api: add a series of orphaned documents

2019-07-15T14:03:02+00:00

There are lots of documents under Documentation/*.txt and a few other
orphan documents elsehwere that belong to the driver-API book.

Move them to their right place.

Reviewed-by: Cornelia Huck  # vfio-related parts
Acked-by: Logan Gunthorpe  # switchtec
Signed-off-by: Mauro Carvalho Chehab