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Diffstat (limited to 'Documentation/driver-api/pwm.rst')
| -rw-r--r-- | Documentation/driver-api/pwm.rst | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst index ccb06e485756..8c71a2055d27 100644 --- a/Documentation/driver-api/pwm.rst +++ b/Documentation/driver-api/pwm.rst @@ -40,8 +40,7 @@ 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 the getter, devm_pwm_get(), devm_of_pwm_get(), -devm_fwnode_pwm_get(), also exist. +variants of the getter, devm_pwm_get() and devm_fwnode_pwm_get(), also exist. After being requested, a PWM has to be configured using:: @@ -49,6 +48,12 @@ 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. + +As a consumer, don't rely on the output's state for a disabled PWM. If it's +easily possible, drivers are supposed to emit the inactive state, but some +drivers cannot. If you rely on getting the inactive state, use .duty_cycle=0, +.enabled=true. + 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 |