Merge tag 'pwm/for-4.13-rc1' of...

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

+======================================
 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).
+  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).
+  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).
+  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)) {
+		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;
-	}
+	*prd = div;
+	div *= state->duty_cycle;
+	do_div(div, state->period);
+	*dty = div;
+	*prsclr = prescaler;
 
-	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);
-	}
+	div = (u64)pval * NSEC_PER_SEC * *prd;
+	state->period = DIV_ROUND_CLOSEST_ULL(div, clk_rate);
 
-	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));
-
-	if (clk_gate) {
-		val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
-		val |= clk_gate;
-		sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
-	}
-
-	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;
+
+	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);
-
-	sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+	if ((cstate.period != state->period) ||
+	    (cstate.duty_cycle != state->duty_cycle)) {
+		u32 period, duty, val;
+		unsigned int prescaler;
 
+		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;
+		}
 
-	return 0;
-}
+		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);
 
-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;
+			ctrl &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
+			ctrl |= BIT_CH(prescaler, pwm->hwpwm);
+		}
 
-	ret = clk_prepare_enable(sun4i_pwm->clk);
-	if (ret) {
-		dev_err(chip->dev, "failed to enable PWM clock\n");
-		return 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;
 	}
 
-	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);
+	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);
+	}
+
+	sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
+
 	spin_unlock(&sun4i_pwm->ctrl_lock);
 
+	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[] = {