1 files changed, 213 insertions, 21 deletions

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 5a095eb46b54..bbe7bfdb1549 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -49,6 +49,102 @@ static void pwmchip_unlock(struct pwm_chip *chip)
 
 DEFINE_GUARD(pwmchip, struct pwm_chip *, pwmchip_lock(_T), pwmchip_unlock(_T))
 
+static void pwm_wf2state(const struct pwm_waveform *wf, struct pwm_state *state)
+{
+	if (wf->period_length_ns) {
+		if (wf->duty_length_ns + wf->duty_offset_ns < wf->period_length_ns)
+			*state = (struct pwm_state){
+				.enabled = true,
+				.polarity = PWM_POLARITY_NORMAL,
+				.period = wf->period_length_ns,
+				.duty_cycle = wf->duty_length_ns,
+			};
+		else
+			*state = (struct pwm_state){
+				.enabled = true,
+				.polarity = PWM_POLARITY_INVERSED,
+				.period = wf->period_length_ns,
+				.duty_cycle = wf->period_length_ns - wf->duty_length_ns,
+			};
+	} else {
+		*state = (struct pwm_state){
+			.enabled = false,
+		};
+	}
+}
+
+static void pwm_state2wf(const struct pwm_state *state, struct pwm_waveform *wf)
+{
+	if (state->enabled) {
+		if (state->polarity == PWM_POLARITY_NORMAL)
+			*wf = (struct pwm_waveform){
+				.period_length_ns = state->period,
+				.duty_length_ns = state->duty_cycle,
+				.duty_offset_ns = 0,
+			};
+		else
+			*wf = (struct pwm_waveform){
+				.period_length_ns = state->period,
+				.duty_length_ns = state->period - state->duty_cycle,
+				.duty_offset_ns = state->duty_cycle,
+			};
+	} else {
+		*wf = (struct pwm_waveform){
+			.period_length_ns = 0,
+		};
+	}
+}
+
+static bool pwm_check_rounding(const struct pwm_waveform *wf,
+			       const struct pwm_waveform *wf_rounded)
+{
+	if (!wf->period_length_ns)
+		return true;
+
+	if (wf->period_length_ns < wf_rounded->period_length_ns)
+		return false;
+
+	if (wf->duty_length_ns < wf_rounded->duty_length_ns)
+		return false;
+
+	if (wf->duty_offset_ns < wf_rounded->duty_offset_ns)
+		return false;
+
+	return true;
+}
+
+static int __pwm_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm,
+				     const struct pwm_waveform *wf, void *wfhw)
+{
+	const struct pwm_ops *ops = chip->ops;
+
+	return ops->round_waveform_tohw(chip, pwm, wf, wfhw);
+}
+
+static int __pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
+				       const void *wfhw, struct pwm_waveform *wf)
+{
+	const struct pwm_ops *ops = chip->ops;
+
+	return ops->round_waveform_fromhw(chip, pwm, wfhw, wf);
+}
+
+static int __pwm_read_waveform(struct pwm_chip *chip, struct pwm_device *pwm, void *wfhw)
+{
+	const struct pwm_ops *ops = chip->ops;
+
+	return ops->read_waveform(chip, pwm, wfhw);
+}
+
+static int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, const void *wfhw)
+{
+	const struct pwm_ops *ops = chip->ops;
+
+	return ops->write_waveform(chip, pwm, wfhw);
+}
+
+#define WFHWSIZE 20
+
 static void pwm_apply_debug(struct pwm_device *pwm,
 			    const struct pwm_state *state)
 {
@@ -182,6 +278,7 @@ static bool pwm_state_valid(const struct pwm_state *state)
 static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
 {
 	struct pwm_chip *chip;
+	const struct pwm_ops *ops;
 	int err;
 
 	if (!pwm || !state)
@@ -205,6 +302,7 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
 	}
 
 	chip = pwm->chip;
+	ops = chip->ops;
 
 	if (state->period == pwm->state.period &&
 	    state->duty_cycle == pwm->state.duty_cycle &&
@@ -213,18 +311,69 @@ static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
 	    state->usage_power == pwm->state.usage_power)
 		return 0;
 
-	err = chip->ops->apply(chip, pwm, state);
-	trace_pwm_apply(pwm, state, err);
-	if (err)
-		return err;
+	if (ops->write_waveform) {
+		struct pwm_waveform wf;
+		char wfhw[WFHWSIZE];
 
-	pwm->state = *state;
+		BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
 
-	/*
-	 * only do this after pwm->state was applied as some
-	 * implementations of .get_state depend on this
-	 */
-	pwm_apply_debug(pwm, state);
+		pwm_state2wf(state, &wf);
+
+		/*
+		 * The rounding is wrong here for states with inverted polarity.
+		 * While .apply() rounds down duty_cycle (which represents the
+		 * time from the start of the period to the inner edge),
+		 * .round_waveform_tohw() rounds down the time the PWM is high.
+		 * Can be fixed if the need arises, until reported otherwise
+		 * let's assume that consumers don't care.
+		 */
+
+		err = __pwm_round_waveform_tohw(chip, pwm, &wf, &wfhw);
+		if (err) {
+			if (err > 0)
+				/*
+				 * This signals an invalid request, typically
+				 * the requested period (or duty_offset) is
+				 * smaller than possible with the hardware.
+				 */
+				return -EINVAL;
+
+			return err;
+		}
+
+		if (IS_ENABLED(CONFIG_PWM_DEBUG)) {
+			struct pwm_waveform wf_rounded;
+
+			err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
+			if (err)
+				return err;
+
+			if (!pwm_check_rounding(&wf, &wf_rounded))
+				dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
+					wf.duty_length_ns, wf.period_length_ns, wf.duty_offset_ns,
+					wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
+		}
+
+		err = __pwm_write_waveform(chip, pwm, &wfhw);
+		if (err)
+			return err;
+
+		pwm->state = *state;
+
+	} else {
+		err = ops->apply(chip, pwm, state);
+		trace_pwm_apply(pwm, state, err);
+		if (err)
+			return err;
+
+		pwm->state = *state;
+
+		/*
+		 * only do this after pwm->state was applied as some
+		 * implementations of .get_state() depend on this
+		 */
+		pwm_apply_debug(pwm, state);
+	}
 
 	return 0;
 }
@@ -292,6 +441,41 @@ 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)
+{
+	struct pwm_chip *chip = pwm->chip;
+	const struct pwm_ops *ops = chip->ops;
+	int ret = -EOPNOTSUPP;
+
+	if (ops->read_waveform) {
+		char wfhw[WFHWSIZE];
+		struct pwm_waveform wf;
+
+		BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
+
+		scoped_guard(pwmchip, chip) {
+
+			ret = __pwm_read_waveform(chip, pwm, &wfhw);
+			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);
+
+		trace_pwm_get(pwm, state, ret);
+	}
+
+	return ret;
+}
+
 /**
  * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
  * @pwm: PWM device
@@ -435,7 +619,7 @@ err_get_device:
 		}
 	}
 
-	if (ops->get_state) {
+	if (ops->read_waveform || ops->get_state) {
 		/*
 		 * Zero-initialize state because most drivers are unaware of
 		 * .usage_power. The other members of state are supposed to be
@@ -445,11 +629,7 @@ err_get_device:
 		 */
 		struct pwm_state state = { 0, };
 
-		scoped_guard(pwmchip, chip)
-			err = ops->get_state(chip, pwm, &state);
-
-		trace_pwm_get(pwm, &state, err);
-
+		err = pwm_get_state_hw(pwm, &state);
 		if (!err)
 			pwm->state = state;
 
@@ -1136,12 +1316,24 @@ static bool pwm_ops_check(const struct pwm_chip *chip)
 {
 	const struct pwm_ops *ops = chip->ops;
 
-	if (!ops->apply)
-		return false;
+	if (ops->write_waveform) {
+		if (!ops->round_waveform_tohw ||
+		    !ops->round_waveform_fromhw ||
+		    !ops->write_waveform)
+			return false;
 
-	if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
-		dev_warn(pwmchip_parent(chip),
-			 "Please implement the .get_state() callback\n");
+		if (WFHWSIZE < ops->sizeof_wfhw) {
+			dev_warn(pwmchip_parent(chip), "WFHWSIZE < %zu\n", ops->sizeof_wfhw);
+			return false;
+		}
+	} else {
+		if (!ops->apply)
+			return false;
+
+		if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
+			dev_warn(pwmchip_parent(chip),
+				 "Please implement the .get_state() callback\n");
+	}
 
 	return true;
 }