Merge tag 'pwm/for-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This release cycle's changes include mostly updates and cleanups to
  existing drivers along with a few cleanups to the core, documentation
  and device tree bindings"

* tag 'pwm/for-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: cros-ec: Fix transposed param settings
  pwm: meson: Improve PWM calculation precision
  dt-bindings: pwm: meson: Add compatible for gxbb ao PWMs
  pwm: meson: Add compatible for the gxbb ao PWMs
  pwm: sun4i: Drop legacy callbacks
  pwm: sun4i: Switch to atomic PWM
  pwm: sun4i: Improve hardware read out
  pwm: hibvt: Constify hibvt_pwm_ops
  pwm: Silently error out on EPROBE_DEFER
  pwm: Standardize document format
  pwm: bfin: Remove unneeded error message
  dt-bindings: pwm: Update STM32 timers clock names
  dt-bindings: pwm: Add R-Car M3-W device tree bindings
  pwm: tegra: Set maximum pwm clock source per SoC tapeout

Documentation/devicetree/bindings/pwm/pwm-meson.txt

@@ -2,7 +2,9 @@ Amlogic Meson PWM Controller
 ============================
 
 Required properties:
-- compatible: Shall contain "amlogic,meson8b-pwm" or "amlogic,meson-gxbb-pwm".
+- compatible: Shall contain "amlogic,meson8b-pwm"
+                         or "amlogic,meson-gxbb-pwm"
+                         or "amlogic,meson-gxbb-ao-pwm"
 - #pwm-cells: Should be 3. See pwm.txt in this directory for a description of
   the cells format.
 

Documentation/devicetree/bindings/pwm/pwm-stm32.txt

@@ -24,7 +24,7 @@ Example:
 		compatible = "st,stm32-timers";
 		reg = <0x40010000 0x400>;
 		clocks = <&rcc 0 160>;
-		clock-names = "clk_int";
+		clock-names = "int";
 
 		pwm {
 			compatible = "st,stm32-pwm";

Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt

@@ -8,6 +8,7 @@ Required Properties:
  - "renesas,pwm-r8a7791": for R-Car M2-W
  - "renesas,pwm-r8a7794": for R-Car E2
  - "renesas,pwm-r8a7795": for R-Car H3
+ - "renesas,pwm-r8a7796": for R-Car M3-W
 - reg: base address and length of the registers block for the PWM.
 - #pwm-cells: should be 2. See pwm.txt in this directory for a description of
   the cells format.

Documentation/pwm.txt

@@ -1,4 +1,6 @@
+======================================
 Pulse Width Modulation (PWM) interface
+======================================
 
 This provides an overview about the Linux PWM interface
 
@@ -16,7 +18,7 @@ Users of the legacy PWM API use unique IDs to refer to PWM devices.
 
 Instead of referring to a PWM device via its unique ID, board setup code
 should instead register a static mapping that can be used to match PWM
-consumers to providers, as given in the following example:
+consumers to providers, as given in the following example::
 
 	static struct pwm_lookup board_pwm_lookup[] = {
 		PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL,
@@ -40,9 +42,9 @@ New users should use the pwm_get() function and pass to it the consumer
 device or a consumer name. pwm_put() is used to free the PWM device. Managed
 variants of these functions, devm_pwm_get() and devm_pwm_put(), also exist.
 
-After being requested, a PWM has to be configured using:
+After being requested, a PWM has to be configured using::
 
-int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
+	int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
 
 This API controls both the PWM period/duty_cycle config and the
 enable/disable state.
@@ -72,11 +74,14 @@ interface is provided to use the PWMs from userspace. It is exposed at
 pwmchipN, where N is the base of the PWM chip. Inside the directory you
 will find:
 
-npwm - The number of PWM channels this chip supports (read-only).
+  npwm
+    The number of PWM channels this chip supports (read-only).
 
-export - Exports a PWM channel for use with sysfs (write-only).
+  export
+    Exports a PWM channel for use with sysfs (write-only).
 
-unexport - Unexports a PWM channel from sysfs (write-only).
+  unexport
+   Unexports a PWM channel from sysfs (write-only).
 
 The PWM channels are numbered using a per-chip index from 0 to npwm-1.
 
@@ -84,21 +89,26 @@ When a PWM channel is exported a pwmX directory will be created in the
 pwmchipN directory it is associated with, where X is the number of the
 channel that was exported. The following properties will then be available:
 
-period - The total period of the PWM signal (read/write).
-	Value is in nanoseconds and is the sum of the active and inactive
-	time of the PWM.
+  period
+    The total period of the PWM signal (read/write).
+    Value is in nanoseconds and is the sum of the active and inactive
+    time of the PWM.
 
-duty_cycle - The active time of the PWM signal (read/write).
-	Value is in nanoseconds and must be less than the period.
+  duty_cycle
+    The active time of the PWM signal (read/write).
+    Value is in nanoseconds and must be less than the period.
 
-polarity - Changes the polarity of the PWM signal (read/write).
-	Writes to this property only work if the PWM chip supports changing
-	the polarity. The polarity can only be changed if the PWM is not
-	enabled. Value is the string "normal" or "inversed".
+  polarity
+    Changes the polarity of the PWM signal (read/write).
+    Writes to this property only work if the PWM chip supports changing
+    the polarity. The polarity can only be changed if the PWM is not
+    enabled. Value is the string "normal" or "inversed".
 
-enable - Enable/disable the PWM signal (read/write).
-	0 - disabled
-	1 - enabled
+  enable
+    Enable/disable the PWM signal (read/write).
+
+	- 0 - disabled
+	- 1 - enabled
 
 Implementing a PWM driver
 -------------------------

drivers/pwm/core.c

@@ -678,7 +678,9 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 
 	pc = of_node_to_pwmchip(args.np);
 	if (IS_ERR(pc)) {
-		pr_err("%s(): PWM chip not found\n", __func__);
+		if (PTR_ERR(pc) != -EPROBE_DEFER)
+			pr_err("%s(): PWM chip not found\n", __func__);
+
 		pwm = ERR_CAST(pc);
 		goto put;
 	}

drivers/pwm/pwm-bfin.c

@@ -118,10 +118,8 @@ static int bfin_pwm_probe(struct platform_device *pdev)
 	int ret;
 
 	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
-	if (!pwm) {
-		dev_err(&pdev->dev, "failed to allocate memory\n");
+	if (!pwm)
 		return -ENOMEM;
-	}
 
 	platform_set_drvdata(pdev, pwm);
 

drivers/pwm/pwm-cros-ec.c

@@ -75,8 +75,8 @@ static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
 
 	msg->version = 0;
 	msg->command = EC_CMD_PWM_GET_DUTY;
-	msg->insize = sizeof(*params);
-	msg->outsize = sizeof(*resp);
+	msg->insize = sizeof(*resp);
+	msg->outsize = sizeof(*params);
 
 	params->pwm_type = EC_PWM_TYPE_GENERIC;
 	params->index = index;

drivers/pwm/pwm-hibvt.c

@@ -165,7 +165,7 @@ static int hibvt_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
-static struct pwm_ops hibvt_pwm_ops = {
+static const struct pwm_ops hibvt_pwm_ops = {
 	.get_state = hibvt_pwm_get_state,
 	.apply = hibvt_pwm_apply,
 

drivers/pwm/pwm-meson.c

@@ -103,6 +103,7 @@ struct meson_pwm_channel {
 
 struct meson_pwm_data {
 	const char * const *parent_names;
+	unsigned int num_parents;
 };
 
 struct meson_pwm {
@@ -162,7 +163,8 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 			  unsigned int duty, unsigned int period)
 {
 	unsigned int pre_div, cnt, duty_cnt;
-	unsigned long fin_freq = -1, fin_ns;
+	unsigned long fin_freq = -1;
+	u64 fin_ps;
 
 	if (~(meson->inverter_mask >> id) & 0x1)
 		duty = period - duty;
@@ -178,13 +180,15 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 	}
 
 	dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
-	fin_ns = NSEC_PER_SEC / fin_freq;
+	fin_ps = (u64)NSEC_PER_SEC * 1000;
+	do_div(fin_ps, fin_freq);
 
 	/* Calc pre_div with the period */
 	for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
-		cnt = DIV_ROUND_CLOSEST(period, fin_ns * (pre_div + 1));
-		dev_dbg(meson->chip.dev, "fin_ns=%lu pre_div=%u cnt=%u\n",
-			fin_ns, pre_div, cnt);
+		cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
+					    fin_ps * (pre_div + 1));
+		dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
+			fin_ps, pre_div, cnt);
 		if (cnt <= 0xffff)
 			break;
 	}
@@ -207,7 +211,8 @@ static int meson_pwm_calc(struct meson_pwm *meson,
 		channel->lo = cnt;
 	} else {
 		/* Then check is we can have the duty with the same pre_div */
-		duty_cnt = DIV_ROUND_CLOSEST(duty, fin_ns * (pre_div + 1));
+		duty_cnt = DIV_ROUND_CLOSEST_ULL((u64)duty * 1000,
+						 fin_ps * (pre_div + 1));
 		if (duty_cnt > 0xffff) {
 			dev_err(meson->chip.dev, "unable to get duty cycle\n");
 			return -EINVAL;
@@ -381,6 +386,7 @@ static const char * const pwm_meson8b_parent_names[] = {
 
 static const struct meson_pwm_data pwm_meson8b_data = {
 	.parent_names = pwm_meson8b_parent_names,
+	.num_parents = ARRAY_SIZE(pwm_meson8b_parent_names),
 };
 
 static const char * const pwm_gxbb_parent_names[] = {
@@ -389,11 +395,35 @@ static const char * const pwm_gxbb_parent_names[] = {
 
 static const struct meson_pwm_data pwm_gxbb_data = {
 	.parent_names = pwm_gxbb_parent_names,
+	.num_parents = ARRAY_SIZE(pwm_gxbb_parent_names),
+};
+
+/*
+ * Only the 2 first inputs of the GXBB AO PWMs are valid
+ * The last 2 are grounded
+ */
+static const char * const pwm_gxbb_ao_parent_names[] = {
+	"xtal", "clk81"
+};
+
+static const struct meson_pwm_data pwm_gxbb_ao_data = {
+	.parent_names = pwm_gxbb_ao_parent_names,
+	.num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_names),
 };
 
 static const struct of_device_id meson_pwm_matches[] = {
-	{ .compatible = "amlogic,meson8b-pwm", .data = &pwm_meson8b_data },
-	{ .compatible = "amlogic,meson-gxbb-pwm", .data = &pwm_gxbb_data },
+	{
+		.compatible = "amlogic,meson8b-pwm",
+		.data = &pwm_meson8b_data
+	},
+	{
+		.compatible = "amlogic,meson-gxbb-pwm",
+		.data = &pwm_gxbb_data
+	},
+	{
+		.compatible = "amlogic,meson-gxbb-ao-pwm",
+		.data = &pwm_gxbb_ao_data
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, meson_pwm_matches);
@@ -417,7 +447,7 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
 		init.ops = &clk_mux_ops;
 		init.flags = CLK_IS_BASIC;
 		init.parent_names = meson->data->parent_names;
-		init.num_parents = 1 << MISC_CLK_SEL_WIDTH;
+		init.num_parents = meson->data->num_parents;
 
 		channel->mux.reg = meson->base + REG_MISC_AB;
 		channel->mux.shift = mux_reg_shifts[i];

drivers/pwm/pwm-sun4i.c

@@ -8,8 +8,10 @@
 
 #include <linux/bitops.h>
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -44,6 +46,10 @@
 
 #define PWM_DTY_MASK		GENMASK(15, 0)
 
+#define PWM_REG_PRD(reg)	((((reg) >> 16) & PWM_PRD_MASK) + 1)
+#define PWM_REG_DTY(reg)	((reg) & PWM_DTY_MASK)
+#define PWM_REG_PRESCAL(reg, chan)	(((reg) >> ((chan) * PWMCH_OFFSET)) & PWM_PRESCAL_MASK)
+
 #define BIT_CH(bit, chan)	((bit) << ((chan) * PWMCH_OFFSET))
 
 static const u32 prescaler_table[] = {
@@ -77,6 +83,8 @@ struct sun4i_pwm_chip {
 	void __iomem *base;
 	spinlock_t ctrl_lock;
 	const struct sun4i_pwm_data *data;
+	unsigned long next_period[2];
+	bool needs_delay[2];
 };
 
 static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip)
@@ -96,26 +104,65 @@ static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip,
 	writel(val, chip->base + offset);
 }
 
-static int sun4i_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			    int duty_ns, int period_ns)
+static void sun4i_pwm_get_state(struct pwm_chip *chip,
+				struct pwm_device *pwm,
+				struct pwm_state *state)
 {
 	struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
-	u32 prd, dty, val, clk_gate;
+	u64 clk_rate, tmp;
+	u32 val;
+	unsigned int prescaler;
+
+	clk_rate = clk_get_rate(sun4i_pwm->clk);
+
+	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+
+	if ((val == PWM_PRESCAL_MASK) && sun4i_pwm->data->has_prescaler_bypass)
+		prescaler = 1;
+	else
+		prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)];
+
+	if (prescaler == 0)
+		return;
+
+	if (val & BIT_CH(PWM_ACT_STATE, pwm->hwpwm))
+		state->polarity = PWM_POLARITY_NORMAL;
+	else
+		state->polarity = PWM_POLARITY_INVERSED;
+
+	if (val & BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm))
+		state->enabled = true;
+	else
+		state->enabled = false;
+
+	val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm));
+
+	tmp = prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+
+	tmp = prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
+	state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+}
+
+static int sun4i_pwm_calculate(struct sun4i_pwm_chip *sun4i_pwm,
+			       struct pwm_state *state,
+			       u32 *dty, u32 *prd, unsigned int *prsclr)
+{
 	u64 clk_rate, div = 0;
-	unsigned int prescaler = 0;
-	int err;
+	unsigned int pval, prescaler = 0;
 
 	clk_rate = clk_get_rate(sun4i_pwm->clk);
 
 	if (sun4i_pwm->data->has_prescaler_bypass) {
 		/* First, test without any prescaler when available */
 		prescaler = PWM_PRESCAL_MASK;
+		pval = 1;
 		/*
 		 * When not using any prescaler, the clock period in nanoseconds
 		 * is not an integer so round it half up instead of
 		 * truncating to get less surprising values.
 		 */
-		div = clk_rate * period_ns + NSEC_PER_SEC / 2;
+		div = clk_rate * state->period + NSEC_PER_SEC / 2;
 		do_div(div, NSEC_PER_SEC);
 		if (div - 1 > PWM_PRD_MASK)
 			prescaler = 0;
@@ -126,137 +173,141 @@ static int sun4i_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) {
 			if (!prescaler_table[prescaler])
 				continue;
+			pval = prescaler_table[prescaler];
 			div = clk_rate;
-			do_div(div, prescaler_table[prescaler]);
-			div = div * period_ns;
+			do_div(div, pval);
+			div = div * state->period;
 			do_div(div, NSEC_PER_SEC);
 			if (div - 1 <= PWM_PRD_MASK)
 				break;
 		}
 
-		if (div - 1 > PWM_PRD_MASK) {
-			dev_err(chip->dev, "period exceeds the maximum value\n");
+		if (div - 1 > PWM_PRD_MASK)
 			return -EINVAL;
-		}
-	}
-
-	prd = div;
-	div *= duty_ns;
-	do_div(div, period_ns);
-	dty = div;
-
-	err = clk_prepare_enable(sun4i_pwm->clk);
-	if (err) {
-		dev_err(chip->dev, "failed to enable PWM clock\n");
-		return err;
-	}
-
-	spin_lock(&sun4i_pwm->ctrl_lock);
-	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
-
-	if (sun4i_pwm->data->has_rdy && (val & PWM_RDY(pwm->hwpwm))) {
-		spin_unlock(&sun4i_pwm->ctrl_lock);
-		clk_disable_unprepare(sun4i_pwm->clk);
-		return -EBUSY;
-	}
-
-	clk_gate = val & BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
-	if (clk_gate) {
-		val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
-		sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
 	}
 
-	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
-	val &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
-	val |= BIT_CH(prescaler, pwm->hwpwm);
-	sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
-
-	val = (dty & PWM_DTY_MASK) | PWM_PRD(prd);
-	sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
+	*prd = div;
+	div *= state->duty_cycle;
+	do_div(div, state->period);
+	*dty = div;
+	*prsclr = prescaler;
 
-	if (clk_gate) {
-		val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
-		val |= clk_gate;
-		sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
-	}
+	div = (u64)pval * NSEC_PER_SEC * *prd;
+	state->period = DIV_ROUND_CLOSEST_ULL(div, clk_rate);
 
-	spin_unlock(&sun4i_pwm->ctrl_lock);
-	clk_disable_unprepare(sun4i_pwm->clk);
+	div = (u64)pval * NSEC_PER_SEC * *dty;
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(div, clk_rate);
 
 	return 0;
 }
 
-static int sun4i_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
-				  enum pwm_polarity polarity)
+static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			   struct pwm_state *state)
 {
 	struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
-	u32 val;
+	struct pwm_state cstate;
+	u32 ctrl;
 	int ret;
+	unsigned int delay_us;
+	unsigned long now;
 
-	ret = clk_prepare_enable(sun4i_pwm->clk);
-	if (ret) {
-		dev_err(chip->dev, "failed to enable PWM clock\n");
-		return ret;
+	pwm_get_state(pwm, &cstate);
+
+	if (!cstate.enabled) {
+		ret = clk_prepare_enable(sun4i_pwm->clk);
+		if (ret) {
+			dev_err(chip->dev, "failed to enable PWM clock\n");
+			return ret;
+		}
 	}
 
 	spin_lock(&sun4i_pwm->ctrl_lock);
-	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+	ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
 
-	if (polarity != PWM_POLARITY_NORMAL)
-		val &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
-	else
-		val |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
+	if ((cstate.period != state->period) ||
+	    (cstate.duty_cycle != state->duty_cycle)) {
+		u32 period, duty, val;
+		unsigned int prescaler;
 
-	sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+		ret = sun4i_pwm_calculate(sun4i_pwm, state,
+					  &duty, &period, &prescaler);
+		if (ret) {
+			dev_err(chip->dev, "period exceeds the maximum value\n");
+			spin_unlock(&sun4i_pwm->ctrl_lock);
+			if (!cstate.enabled)
+				clk_disable_unprepare(sun4i_pwm->clk);
+			return ret;
+		}
 
-	spin_unlock(&sun4i_pwm->ctrl_lock);
-	clk_disable_unprepare(sun4i_pwm->clk);
+		if (PWM_REG_PRESCAL(ctrl, pwm->hwpwm) != prescaler) {
+			/* Prescaler changed, the clock has to be gated */
+			ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+			sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
 
-	return 0;
-}
+			ctrl &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
+			ctrl |= BIT_CH(prescaler, pwm->hwpwm);
+		}
 
-static int sun4i_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
-	u32 val;
-	int ret;
+		val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
+		sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
+		sun4i_pwm->next_period[pwm->hwpwm] = jiffies +
+			usecs_to_jiffies(cstate.period / 1000 + 1);
+		sun4i_pwm->needs_delay[pwm->hwpwm] = true;
+	}
 
-	ret = clk_prepare_enable(sun4i_pwm->clk);
-	if (ret) {
-		dev_err(chip->dev, "failed to enable PWM clock\n");
-		return ret;
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
+	else
+		ctrl |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
+
+	ctrl |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+	if (state->enabled) {
+		ctrl |= BIT_CH(PWM_EN, pwm->hwpwm);
+	} else if (!sun4i_pwm->needs_delay[pwm->hwpwm]) {
+		ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
+		ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
 	}
 
-	spin_lock(&sun4i_pwm->ctrl_lock);
-	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
-	val |= BIT_CH(PWM_EN, pwm->hwpwm);
-	val |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
-	sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+	sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
+
 	spin_unlock(&sun4i_pwm->ctrl_lock);
 
-	return 0;
-}
+	if (state->enabled)
+		return 0;
 
-static void sun4i_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
-	u32 val;
+	if (!sun4i_pwm->needs_delay[pwm->hwpwm]) {
+		clk_disable_unprepare(sun4i_pwm->clk);
+		return 0;
+	}
+
+	/* We need a full period to elapse before disabling the channel. */
+	now = jiffies;
+	if (sun4i_pwm->needs_delay[pwm->hwpwm] &&
+	    time_before(now, sun4i_pwm->next_period[pwm->hwpwm])) {
+		delay_us = jiffies_to_usecs(sun4i_pwm->next_period[pwm->hwpwm] -
+					   now);
+		if ((delay_us / 500) > MAX_UDELAY_MS)
+			msleep(delay_us / 1000 + 1);
+		else
+			usleep_range(delay_us, delay_us * 2);
+	}
+	sun4i_pwm->needs_delay[pwm->hwpwm] = false;
 
 	spin_lock(&sun4i_pwm->ctrl_lock);
-	val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
-	val &= ~BIT_CH(PWM_EN, pwm->hwpwm);
-	val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
-	sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+	ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+	ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+	ctrl &= ~BIT_CH(PWM_EN, pwm->hwpwm);
+	sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
 	spin_unlock(&sun4i_pwm->ctrl_lock);
 
 	clk_disable_unprepare(sun4i_pwm->clk);
+
+	return 0;
 }
 
 static const struct pwm_ops sun4i_pwm_ops = {
-	.config = sun4i_pwm_config,
-	.set_polarity = sun4i_pwm_set_polarity,
-	.enable = sun4i_pwm_enable,
-	.disable = sun4i_pwm_disable,
+	.apply = sun4i_pwm_apply,
+	.get_state = sun4i_pwm_get_state,
 	.owner = THIS_MODULE,
 };
 
@@ -316,8 +367,7 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 {
 	struct sun4i_pwm_chip *pwm;
 	struct resource *res;
-	u32 val;
-	int i, ret;
+	int ret;
 	const struct of_device_id *match;
 
 	match = of_match_device(sun4i_pwm_dt_ids, &pdev->dev);
@@ -353,24 +403,7 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pwm);
 
-	ret = clk_prepare_enable(pwm->clk);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to enable PWM clock\n");
-		goto clk_error;
-	}
-
-	val = sun4i_pwm_readl(pwm, PWM_CTRL_REG);
-	for (i = 0; i < pwm->chip.npwm; i++)
-		if (!(val & BIT_CH(PWM_ACT_STATE, i)))
-			pwm_set_polarity(&pwm->chip.pwms[i],
-					 PWM_POLARITY_INVERSED);
-	clk_disable_unprepare(pwm->clk);
-
 	return 0;
-
-clk_error:
-	pwmchip_remove(&pwm->chip);
-	return ret;
 }
 
 static int sun4i_pwm_remove(struct platform_device *pdev)

drivers/pwm/pwm-tegra.c

@@ -41,6 +41,9 @@
 
 struct tegra_pwm_soc {
 	unsigned int num_channels;
+
+	/* Maximum IP frequency for given SoCs */
+	unsigned long max_frequency;
 };
 
 struct tegra_pwm_chip {
@@ -201,7 +204,18 @@ static int tegra_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->clk))
 		return PTR_ERR(pwm->clk);
 
-	/* Read PWM clock rate from source */
+	/* Set maximum frequency of the IP */
+	ret = clk_set_rate(pwm->clk, pwm->soc->max_frequency);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to set max frequency: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * The requested and configured frequency may differ due to
+	 * clock register resolutions. Get the configured frequency
+	 * so that PWM period can be calculated more accurately.
+	 */
 	pwm->clk_rate = clk_get_rate(pwm->clk);
 
 	pwm->rst = devm_reset_control_get(&pdev->dev, "pwm");
@@ -273,10 +287,12 @@ static int tegra_pwm_resume(struct device *dev)
 
 static const struct tegra_pwm_soc tegra20_pwm_soc = {
 	.num_channels = 4,
+	.max_frequency = 48000000UL,
 };
 
 static const struct tegra_pwm_soc tegra186_pwm_soc = {
 	.num_channels = 1,
+	.max_frequency = 102000000UL,
 };
 
 static const struct of_device_id tegra_pwm_of_match[] = {