Export the pwm_get_state_hw() function. This is useful in cases where we want to know what the hardware is actually doing, rather than what what we requested it should do. Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx> --- v4 changes: new patch in v4 And FYI for Uwe and Jonathan, there are a couple of other series introducing PWM conversion triggers that could make use of this so that the sampling_frequency attribute can return the actual rate rather than the requested rate. Already applied: https://lore.kernel.org/linux-iio/20241015-ad7606_add_iio_backend_support-v5-4-654faf1ae08c@xxxxxxxxxxxx/ Under review: https://lore.kernel.org/linux-iio/aea7f92b-3d12-4ced-b1c8-90bcf1d992d3@xxxxxxxxxxxx/T/#m1377d5acd7e996acd1f59038bdd09f0742d3ac35 --- drivers/pwm/core.c | 55 +++++++++++++++++++++++++++++++++++++---------------- include/linux/pwm.h | 1 + 2 files changed, 40 insertions(+), 16 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 634be56e204b..a214d0165d09 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -718,7 +718,7 @@ int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state) } EXPORT_SYMBOL_GPL(pwm_apply_atomic); -static int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) +static int __pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) { struct pwm_chip *chip = pwm->chip; const struct pwm_ops *ops = chip->ops; @@ -730,29 +730,50 @@ static int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) BUG_ON(WFHWSIZE < ops->sizeof_wfhw); - scoped_guard(pwmchip, chip) { - - ret = __pwm_read_waveform(chip, pwm, &wfhw); - if (ret) - return ret; + ret = __pwm_read_waveform(chip, pwm, &wfhw); + if (ret) + return ret; - ret = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf); - if (ret) - return ret; - } + ret = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf); + if (ret) + return ret; pwm_wf2state(&wf, state); } else if (ops->get_state) { - scoped_guard(pwmchip, chip) - ret = ops->get_state(chip, pwm, state); - + ret = ops->get_state(chip, pwm, state); trace_pwm_get(pwm, state, ret); } return ret; } +/** + * pwm_get_state_hw() - get the current PWM state from hardware + * @pwm: PWM device + * @state: state to fill with the current PWM state + * + * Similar to pwm_get_state() but reads the current PWM state from hardware + * instead of the requested state. + * + * Returns: 0 on success or a negative error code on failure. + * Context: May sleep. + */ +int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) +{ + struct pwm_chip *chip = pwm->chip; + + might_sleep(); + + guard(pwmchip)(chip); + + if (!chip->operational) + return -ENODEV; + + return __pwm_get_state_hw(pwm, state); +} +EXPORT_SYMBOL_GPL(pwm_get_state_hw); + /** * pwm_adjust_config() - adjust the current PWM config to the PWM arguments * @pwm: PWM device @@ -906,9 +927,11 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) */ struct pwm_state state = { 0, }; - err = pwm_get_state_hw(pwm, &state); - if (!err) - pwm->state = state; + scoped_guard(pwmchip, chip) { + err = __pwm_get_state_hw(pwm, &state); + if (!err) + pwm->state = state; + } if (IS_ENABLED(CONFIG_PWM_DEBUG)) pwm->last = pwm->state; diff --git a/include/linux/pwm.h b/include/linux/pwm.h index f1cb1e5b0a36..5bcbcf2911c3 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -370,6 +370,7 @@ int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf int pwm_set_waveform_might_sleep(struct pwm_device *pwm, const struct pwm_waveform *wf, bool exact); int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state); int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state); +int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state); int pwm_adjust_config(struct pwm_device *pwm); /** -- 2.43.0
