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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-08 22:18:04 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-08 22:18:04 +0300 |
commit | 8c1bfd746030a14435c9b60d08a81af61332089b (patch) | |
tree | 91f3cf34eac8b319342dd54c600d3adf8cf3e0b3 /Documentation/driver-api | |
parent | b0dfd9af28b60d7ec42c359ae84c1ba97e093100 (diff) | |
parent | bebedf2bb4a9e0cb4ffa72cbc960728051b338a4 (diff) | |
download | linux-8c1bfd746030a14435c9b60d08a81af61332089b.tar.xz |
Merge tag 'pwm/for-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding:
"This contains mostly various fixes, cleanups and some conversions to
the atomic API. One noteworthy change is that PWM consumers can now
pass a hint to the PWM core about the PWM usage, enabling PWM
providers to implement various optimizations.
There's also a fair bit of simplification here with the addition of
some device-managed helpers as well as unification between the DT and
ACPI firmware interfaces"
* tag 'pwm/for-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (50 commits)
pwm: Remove redundant assignment to pointer pwm
pwm: ep93xx: Fix read of uninitialized variable ret
pwm: ep93xx: Prepare clock before using it
pwm: ep93xx: Unfold legacy callbacks into ep93xx_pwm_apply()
pwm: ep93xx: Implement .apply callback
pwm: vt8500: Only unprepare the clock after the pwmchip was removed
pwm: vt8500: Drop if with an always false condition
pwm: tegra: Assert reset only after the PWM was unregistered
pwm: tegra: Don't needlessly enable and disable the clock in .remove()
pwm: tegra: Don't modify HW state in .remove callback
pwm: tegra: Drop an if block with an always false condition
pwm: core: Simplify some devm_*pwm*() functions
pwm: core: Remove unused devm_pwm_put()
pwm: core: Unify fwnode checks in the module
pwm: core: Reuse fwnode_to_pwmchip() in ACPI case
pwm: core: Convert to use fwnode for matching
docs: firmware-guide: ACPI: Add a PWM example
dt-bindings: pwm: pwm-tiecap: Add compatible string for AM64 SoC
dt-bindings: pwm: pwm-tiecap: Convert to json schema
pwm: sprd: Don't check the return code of pwmchip_remove()
...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/driver-model/devres.rst | 3 | ||||
-rw-r--r-- | Documentation/driver-api/pwm.rst | 7 |
2 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst index 0fe1fffa295e..650096523f4f 100644 --- a/Documentation/driver-api/driver-model/devres.rst +++ b/Documentation/driver-api/driver-model/devres.rst @@ -400,7 +400,8 @@ POWER PWM devm_pwm_get() - devm_pwm_put() + devm_of_pwm_get() + devm_fwnode_pwm_get() REGULATOR devm_regulator_bulk_get() diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst index a7ca4f58305a..ccb06e485756 100644 --- a/Documentation/driver-api/pwm.rst +++ b/Documentation/driver-api/pwm.rst @@ -40,7 +40,8 @@ after usage with pwm_free(). New users should use the pwm_get() function and pass to it the consumer device or a consumer name. pwm_put() is used to free the PWM device. Managed -variants of these functions, devm_pwm_get() and devm_pwm_put(), also exist. +variants of the getter, devm_pwm_get(), devm_of_pwm_get(), +devm_fwnode_pwm_get(), also exist. After being requested, a PWM has to be configured using:: @@ -48,6 +49,10 @@ After being requested, a PWM has to be configured using:: This API controls both the PWM period/duty_cycle config and the enable/disable state. +There is also a usage_power setting: If set, the PWM driver is only required to +maintain the power output but has more freedom regarding signal form. +If supported by the driver, the signal can be optimized, for example to improve +EMI by phase shifting the individual channels of a chip. The pwm_config(), pwm_enable() and pwm_disable() functions are just wrappers around pwm_apply_state() and should not be used if the user wants to change |