106 lines
2.6 KiB
Diff
106 lines
2.6 KiB
Diff
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diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
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index d333e7422f4a..f586deaf9d38 100644
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--- a/drivers/pwm/core.c
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+++ b/drivers/pwm/core.c
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@@ -236,7 +236,14 @@ EXPORT_SYMBOL_GPL(pwm_get_chip_data);
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static bool pwm_ops_check(const struct pwm_chip *chip)
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{
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const struct pwm_ops *ops = chip->ops;
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+ /* driver supports legacy, non-atomic operation */
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+ if (ops->config && ops->enable && ops->disable) {
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+ if (IS_ENABLED(CONFIG_PWM_DEBUG))
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+ dev_warn(chip->dev,
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+ "Driver needs updating to atomic API\n");
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+ return true;
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+ }
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if (!ops->apply)
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return false;
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@@ -538,6 +545,73 @@ static void pwm_apply_state_debug(struct pwm_device *pwm,
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}
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}
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+static int pwm_apply_legacy(struct pwm_chip *chip, struct pwm_device *pwm,
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+ const struct pwm_state *state)
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+{
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+ int err;
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+ struct pwm_state initial_state = pwm->state;
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+
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+ if (state->polarity != pwm->state.polarity) {
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+ if (!chip->ops->set_polarity)
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+ return -EINVAL;
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+
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+ /*
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+ * Changing the polarity of a running PWM is only allowed when
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+ * the PWM driver implements ->apply().
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+ */
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+ if (pwm->state.enabled) {
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+ chip->ops->disable(chip, pwm);
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+
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+ /*
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+ * Update pwm->state already here in case
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+ * .set_polarity() or another callback depend on that.
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+ */
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+ pwm->state.enabled = false;
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+ }
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+
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+ err = chip->ops->set_polarity(chip, pwm, state->polarity);
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+ if (err)
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+ goto rollback;
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+
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+ pwm->state.polarity = state->polarity;
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+ }
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+
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+ if (!state->enabled) {
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+ if (pwm->state.enabled)
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+ chip->ops->disable(chip, pwm);
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+
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+ return 0;
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+ }
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+
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+ /*
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+ * We cannot skip calling ->config even if state->period ==
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+ * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
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+ * because we might have exited early in the last call to
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+ * pwm_apply_state because of !state->enabled and so the two values in
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+ * pwm->state might not be configured in hardware.
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+ */
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+ err = chip->ops->config(pwm->chip, pwm,
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+ state->duty_cycle,
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+ state->period);
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+ if (err)
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+ goto rollback;
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+
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+ pwm->state.period = state->period;
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+ pwm->state.duty_cycle = state->duty_cycle;
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+
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+ if (!pwm->state.enabled) {
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+ err = chip->ops->enable(chip, pwm);
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+ if (err)
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+ goto rollback;
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+ }
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+
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+ return 0;
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+
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+rollback:
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+ pwm->state = initial_state;
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+ return err;
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+}
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+
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/**
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* pwm_apply_state() - atomically apply a new state to a PWM device
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* @pwm: PWM device
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@@ -570,7 +644,10 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
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state->usage_power == pwm->state.usage_power)
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return 0;
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- err = chip->ops->apply(chip, pwm, state);
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+ if (chip->ops->apply)
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+ err = chip->ops->apply(chip, pwm, state);
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+ else
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+ err = pwm_apply_legacy(chip, pwm, state);
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if (err)
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return err;
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