pwm: Changes for v5.17-rc1

This contains a number of nice cleanups and improvements for the core
 and various drivers as well as a minor tweak to the json-schema device
 tree bindings.
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Merge tag 'pwm/for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This contains a number of nice cleanups and improvements for the core
  and various drivers, as well as a minor tweak to the json-schema
  device tree bindings"

* tag 'pwm/for-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  dt-bindings: pwm: Avoid selecting schema on node name match
  pwm: img: Use only a single idiom to get a runtime PM reference
  pwm: vt8500: Implement .apply() callback
  pwm: img: Implement .apply() callback
  pwm: twl: Implement .apply() callback
  pwm: Restore initial state if a legacy callback fails
  pwm: Prevent a glitch for legacy drivers
  pwm: Move legacy driver handling into a dedicated function

Documentation/devicetree/bindings/pwm/pwm.yaml

@@ -9,6 +9,8 @@ title: PWM controllers (providers)
 maintainers:
   - Thierry Reding <thierry.reding@gmail.com>
 
+select: false
+
 properties:
   $nodename:
     pattern: "^pwm(@.*|-[0-9a-f])*$"

drivers/pwm/core.c

@@ -548,6 +548,73 @@ static void pwm_apply_state_debug(struct pwm_device *pwm,
 	}
 }
 
+static int pwm_apply_legacy(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	int err;
+	struct pwm_state initial_state = pwm->state;
+
+	if (state->polarity != pwm->state.polarity) {
+		if (!chip->ops->set_polarity)
+			return -EINVAL;
+
+		/*
+		 * Changing the polarity of a running PWM is only allowed when
+		 * the PWM driver implements ->apply().
+		 */
+		if (pwm->state.enabled) {
+			chip->ops->disable(chip, pwm);
+
+			/*
+			 * Update pwm->state already here in case
+			 * .set_polarity() or another callback depend on that.
+			 */
+			pwm->state.enabled = false;
+		}
+
+		err = chip->ops->set_polarity(chip, pwm, state->polarity);
+		if (err)
+			goto rollback;
+
+		pwm->state.polarity = state->polarity;
+	}
+
+	if (!state->enabled) {
+		if (pwm->state.enabled)
+			chip->ops->disable(chip, pwm);
+
+		return 0;
+	}
+
+	/*
+	 * We cannot skip calling ->config even if state->period ==
+	 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
+	 * because we might have exited early in the last call to
+	 * pwm_apply_state because of !state->enabled and so the two values in
+	 * pwm->state might not be configured in hardware.
+	 */
+	err = chip->ops->config(pwm->chip, pwm,
+				state->duty_cycle,
+				state->period);
+	if (err)
+		goto rollback;
+
+	pwm->state.period = state->period;
+	pwm->state.duty_cycle = state->duty_cycle;
+
+	if (!pwm->state.enabled) {
+		err = chip->ops->enable(chip, pwm);
+		if (err)
+			goto rollback;
+	}
+
+	return 0;
+
+rollback:
+	pwm->state = initial_state;
+	return err;
+}
+
 /**
  * pwm_apply_state() - atomically apply a new state to a PWM device
  * @pwm: PWM device
@@ -580,70 +647,22 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 	    state->usage_power == pwm->state.usage_power)
 		return 0;
 
-	if (chip->ops->apply) {
+	if (chip->ops->apply)
 		err = chip->ops->apply(chip, pwm, state);
-		if (err)
-			return err;
+	else
+		err = pwm_apply_legacy(chip, pwm, state);
+	if (err)
+		return err;
 
-		trace_pwm_apply(pwm, state);
+	trace_pwm_apply(pwm, state);
 
-		pwm->state = *state;
+	pwm->state = *state;
 
-		/*
-		 * only do this after pwm->state was applied as some
-		 * implementations of .get_state depend on this
-		 */
-		pwm_apply_state_debug(pwm, state);
-	} else {
-		/*
-		 * FIXME: restore the initial state in case of error.
-		 */
-		if (state->polarity != pwm->state.polarity) {
-			if (!chip->ops->set_polarity)
-				return -EINVAL;
-
-			/*
-			 * Changing the polarity of a running PWM is
-			 * only allowed when the PWM driver implements
-			 * ->apply().
-			 */
-			if (pwm->state.enabled) {
-				chip->ops->disable(chip, pwm);
-				pwm->state.enabled = false;
-			}
-
-			err = chip->ops->set_polarity(chip, pwm,
-						      state->polarity);
-			if (err)
-				return err;
-
-			pwm->state.polarity = state->polarity;
-		}
-
-		if (state->period != pwm->state.period ||
-		    state->duty_cycle != pwm->state.duty_cycle) {
-			err = chip->ops->config(pwm->chip, pwm,
-						state->duty_cycle,
-						state->period);
-			if (err)
-				return err;
-
-			pwm->state.duty_cycle = state->duty_cycle;
-			pwm->state.period = state->period;
-		}
-
-		if (state->enabled != pwm->state.enabled) {
-			if (state->enabled) {
-				err = chip->ops->enable(chip, pwm);
-				if (err)
-					return err;
-			} else {
-				chip->ops->disable(chip, pwm);
-			}
-
-			pwm->state.enabled = state->enabled;
-		}
-	}
+	/*
+	 * only do this after pwm->state was applied as some
+	 * implementations of .get_state depend on this
+	 */
+	pwm_apply_state_debug(pwm, state);
 
 	return 0;
 }

drivers/pwm/pwm-img.c

@@ -128,11 +128,9 @@ static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
 
-	ret = pm_runtime_get_sync(chip->dev);
-	if (ret < 0) {
-		pm_runtime_put_autosuspend(chip->dev);
+	ret = pm_runtime_resume_and_get(chip->dev);
+	if (ret < 0)
 		return ret;
-	}
 
 	val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
 	val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
@@ -184,10 +182,33 @@ static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	pm_runtime_put_autosuspend(chip->dev);
 }
 
+static int img_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			 const struct pwm_state *state)
+{
+	int err;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		if (pwm->state.enabled)
+			img_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = img_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!pwm->state.enabled)
+		err = img_pwm_enable(chip, pwm);
+
+	return err;
+}
+
 static const struct pwm_ops img_pwm_ops = {
-	.config = img_pwm_config,
-	.enable = img_pwm_enable,
-	.disable = img_pwm_disable,
+	.apply = img_pwm_apply,
 	.owner = THIS_MODULE,
 };
 

drivers/pwm/pwm-twl.c

@@ -58,9 +58,9 @@ static inline struct twl_pwm_chip *to_twl(struct pwm_chip *chip)
 }
 
 static int twl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			      int duty_ns, int period_ns)
+			  u64 duty_ns, u64 period_ns)
 {
-	int duty_cycle = DIV_ROUND_UP(duty_ns * TWL_PWM_MAX, period_ns) + 1;
+	int duty_cycle = DIV64_U64_ROUND_UP(duty_ns * TWL_PWM_MAX, period_ns) + 1;
 	u8 pwm_config[2] = { 1, 0 };
 	int base, ret;
 
@@ -279,19 +279,65 @@ static void twl6030_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	mutex_unlock(&twl->mutex);
 }
 
+static int twl4030_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			     const struct pwm_state *state)
+{
+	int err;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		if (pwm->state.enabled)
+			twl4030_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = twl_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!pwm->state.enabled)
+		err = twl4030_pwm_enable(chip, pwm);
+
+	return err;
+}
+
+static int twl6030_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			     const struct pwm_state *state)
+{
+	int err;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		if (pwm->state.enabled)
+			twl6030_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = twl_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!pwm->state.enabled)
+		err = twl6030_pwm_enable(chip, pwm);
+
+	return err;
+}
+
 static const struct pwm_ops twl4030_pwm_ops = {
-	.config = twl_pwm_config,
-	.enable = twl4030_pwm_enable,
-	.disable = twl4030_pwm_disable,
+	.apply = twl4030_pwm_apply,
 	.request = twl4030_pwm_request,
 	.free = twl4030_pwm_free,
 	.owner = THIS_MODULE,
 };
 
 static const struct pwm_ops twl6030_pwm_ops = {
-	.config = twl_pwm_config,
-	.enable = twl6030_pwm_enable,
-	.disable = twl6030_pwm_disable,
+	.apply = twl6030_pwm_apply,
 	.owner = THIS_MODULE,
 };
 

drivers/pwm/pwm-vt8500.c

@@ -70,7 +70,7 @@ static inline void vt8500_pwm_busy_wait(struct vt8500_chip *vt8500, int nr, u8 b
 }
 
 static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-		int duty_ns, int period_ns)
+		u64 duty_ns, u64 period_ns)
 {
 	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);
 	unsigned long long c;
@@ -102,8 +102,8 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 	c = (unsigned long long)pv * duty_ns;
-	do_div(c, period_ns);
-	dc = c;
+
+	dc = div64_u64(c, period_ns);
 
 	writel(prescale, vt8500->base + REG_SCALAR(pwm->hwpwm));
 	vt8500_pwm_busy_wait(vt8500, pwm->hwpwm, STATUS_SCALAR_UPDATE);
@@ -176,11 +176,54 @@ static int vt8500_pwm_set_polarity(struct pwm_chip *chip,
 	return 0;
 }
 
+static int vt8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	int err;
+	bool enabled = pwm->state.enabled;
+
+	if (state->polarity != pwm->state.polarity) {
+		/*
+		 * Changing the polarity of a running PWM is only allowed when
+		 * the PWM driver implements ->apply().
+		 */
+		if (enabled) {
+			vt8500_pwm_disable(chip, pwm);
+
+			enabled = false;
+		}
+
+		err = vt8500_pwm_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			vt8500_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	/*
+	 * We cannot skip calling ->config even if state->period ==
+	 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
+	 * because we might have exited early in the last call to
+	 * pwm_apply_state because of !state->enabled and so the two values in
+	 * pwm->state might not be configured in hardware.
+	 */
+	err = vt8500_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!enabled)
+		err = vt8500_pwm_enable(chip, pwm);
+
+	return err;
+}
+
 static const struct pwm_ops vt8500_pwm_ops = {
-	.enable = vt8500_pwm_enable,
-	.disable = vt8500_pwm_disable,
-	.config = vt8500_pwm_config,
-	.set_polarity = vt8500_pwm_set_polarity,
+	.apply = vt8500_pwm_apply,
 	.owner = THIS_MODULE,
 };