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authorLinus Torvalds2021-07-08 12:18:04 -0700
committerLinus Torvalds2021-07-08 12:18:04 -0700
commit8c1bfd746030a14435c9b60d08a81af61332089b (patch)
tree91f3cf34eac8b319342dd54c600d3adf8cf3e0b3 /Documentation/driver-api
parentb0dfd9af28b60d7ec42c359ae84c1ba97e093100 (diff)
parentbebedf2bb4a9e0cb4ffa72cbc960728051b338a4 (diff)
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.rst3
-rw-r--r--Documentation/driver-api/pwm.rst7
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