@@ -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;
@@ -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);
/**
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@baylibre.com> --- 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@baylibre.com/ Under review: https://lore.kernel.org/linux-iio/aea7f92b-3d12-4ced-b1c8-90bcf1d992d3@baylibre.com/T/#m1377d5acd7e996acd1f59038bdd09f0742d3ac35 --- drivers/pwm/core.c | 55 +++++++++++++++++++++++++++++++++++++---------------- include/linux/pwm.h | 1 + 2 files changed, 40 insertions(+), 16 deletions(-)