Merge tag 'pwm/for-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This adds support for the PWM controller found on Toshiba Visconti
  SoCs and converts a couple of drivers to the atomic API.

  There's also a bunch of cleanups and minor fixes across the board"

* tag 'pwm/for-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (35 commits)
  pwm: Reword docs about pwm_apply_state()
  pwm: atmel: Improve duty cycle calculation in .apply()
  pwm: atmel: Fix duty cycle calculation in .get_state()
  pwm: visconti: Add Toshiba Visconti SoC PWM support
  dt-bindings: pwm: Add bindings for Toshiba Visconti PWM Controller
  arm64: dts: rockchip: Remove clock-names from PWM nodes
  ARM: dts: rockchip: Remove clock-names from PWM nodes
  dt-bindings: pwm: rockchip: Add more compatible strings
  dt-bindings: pwm: Convert pwm-rockchip.txt to YAML
  pwm: mediatek: Remove unused function
  pwm: pca9685: Improve runtime PM behavior
  pwm: pca9685: Support hardware readout
  pwm: pca9685: Switch to atomic API
  pwm: lpss: Don't modify HW state in .remove callback
  pwm: sti: Free resources only after pwmchip_remove()
  pwm: sti: Don't modify HW state in .remove callback
  pwm: lpc3200: Don't modify HW state in .remove callback
  pwm: lpc18xx-sct: Free resources only after pwmchip_remove()
  pwm: bcm-kona: Don't modify HW state in .remove callback
  pwm: bcm2835: Free resources only after pwmchip_remove()
  ...

58 files changed, 466 insertions, 349 deletions

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index d3371ac7b871..c76adedd58c9 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -618,6 +618,15 @@ config PWM_TWL_LED
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-twl-led.
 
+config PWM_VISCONTI
+	tristate "Toshiba Visconti PWM support"
+	depends on ARCH_VISCONTI || COMPILE_TEST
+	help
+	  PWM Subsystem driver support for Toshiba Visconti SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-visconti.
+
 config PWM_VT8500
 	tristate "vt8500 PWM support"
 	depends on ARCH_VT8500 || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index d3879619bd76..708840b7fba8 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -58,4 +58,5 @@ obj-$(CONFIG_PWM_TIECAP)	+= pwm-tiecap.o
 obj-$(CONFIG_PWM_TIEHRPWM)	+= pwm-tiehrpwm.o
 obj-$(CONFIG_PWM_TWL)		+= pwm-twl.o
 obj-$(CONFIG_PWM_TWL_LED)	+= pwm-twl-led.o
+obj-$(CONFIG_PWM_VISCONTI)	+= pwm-visconti.o
 obj-$(CONFIG_PWM_VT8500)	+= pwm-vt8500.o
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index a8eff4b3ee36..c4d5c0667137 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -37,23 +37,13 @@ static struct pwm_device *pwm_to_device(unsigned int pwm)
 	return radix_tree_lookup(&pwm_tree, pwm);
 }
 
-static int alloc_pwms(int pwm, unsigned int count)
+static int alloc_pwms(unsigned int count)
 {
-	unsigned int from = 0;
 	unsigned int start;
 
-	if (pwm >= MAX_PWMS)
-		return -EINVAL;
-
-	if (pwm >= 0)
-		from = pwm;
-
-	start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, from,
+	start = bitmap_find_next_zero_area(allocated_pwms, MAX_PWMS, 0,
 					   count, 0);
 
-	if (pwm >= 0 && start != pwm)
-		return -EEXIST;
-
 	if (start + count > MAX_PWMS)
 		return -ENOSPC;
 
@@ -260,18 +250,14 @@ static bool pwm_ops_check(const struct pwm_chip *chip)
 }
 
 /**
- * pwmchip_add_with_polarity() - register a new PWM chip
+ * pwmchip_add() - register a new PWM chip
  * @chip: the PWM chip to add
- * @polarity: initial polarity of PWM channels
  *
- * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
- * will be used. The initial polarity for all channels is specified by the
- * @polarity parameter.
+ * Register a new PWM chip.
  *
  * Returns: 0 on success or a negative error code on failure.
  */
-int pwmchip_add_with_polarity(struct pwm_chip *chip,
-			      enum pwm_polarity polarity)
+int pwmchip_add(struct pwm_chip *chip)
 {
 	struct pwm_device *pwm;
 	unsigned int i;
@@ -285,25 +271,24 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
 
 	mutex_lock(&pwm_lock);
 
-	ret = alloc_pwms(chip->base, chip->npwm);
+	ret = alloc_pwms(chip->npwm);
 	if (ret < 0)
 		goto out;
 
+	chip->base = ret;
+
 	chip->pwms = kcalloc(chip->npwm, sizeof(*pwm), GFP_KERNEL);
 	if (!chip->pwms) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	chip->base = ret;
-
 	for (i = 0; i < chip->npwm; i++) {
 		pwm = &chip->pwms[i];
 
 		pwm->chip = chip;
 		pwm->pwm = chip->base + i;
 		pwm->hwpwm = i;
-		pwm->state.polarity = polarity;
 
 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 	}
@@ -326,21 +311,6 @@ out:
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
-
-/**
- * pwmchip_add() - register a new PWM chip
- * @chip: the PWM chip to add
- *
- * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
- * will be used. The initial polarity for all channels is normal.
- *
- * Returns: 0 on success or a negative error code on failure.
- */
-int pwmchip_add(struct pwm_chip *chip)
-{
-	return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
-}
 EXPORT_SYMBOL_GPL(pwmchip_add);
 
 /**
@@ -607,7 +577,7 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 		 */
 		if (state->polarity != pwm->state.polarity) {
 			if (!chip->ops->set_polarity)
-				return -ENOTSUPP;
+				return -EINVAL;
 
 			/*
 			 * Changing the polarity of a running PWM is
diff --git a/drivers/pwm/pwm-ab8500.c b/drivers/pwm/pwm-ab8500.c
index 58c6c0f5b0ec..e2a26d9da25b 100644
--- a/drivers/pwm/pwm-ab8500.c
+++ b/drivers/pwm/pwm-ab8500.c
@@ -24,23 +24,37 @@ struct ab8500_pwm_chip {
 	struct pwm_chip chip;
 };
 
-static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			     int duty_ns, int period_ns)
+static int ab8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
 {
-	int ret = 0;
-	unsigned int higher_val, lower_val;
+	int ret;
 	u8 reg;
+	unsigned int higher_val, lower_val;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		ret = abx500_mask_and_set_register_interruptible(chip->dev,
+					AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
+					1 << (chip->base - 1), 0);
+
+		if (ret < 0)
+			dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
+								pwm->label, ret);
+		return ret;
+	}
 
 	/*
 	 * get the first 8 bits that are be written to
 	 * AB8500_PWM_OUT_CTRL1_REG[0:7]
 	 */
-	lower_val = duty_ns & 0x00FF;
+	lower_val = state->duty_cycle & 0x00FF;
 	/*
 	 * get bits [9:10] that are to be written to
 	 * AB8500_PWM_OUT_CTRL2_REG[0:1]
 	 */
-	higher_val = ((duty_ns & 0x0300) >> 8);
+	higher_val = ((state->duty_cycle & 0x0300) >> 8);
 
 	reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
 
@@ -48,15 +62,11 @@ static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			reg, (u8)lower_val);
 	if (ret < 0)
 		return ret;
+
 	ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
 			(reg + 1), (u8)higher_val);
-
-	return ret;
-}
-
-static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	int ret;
+	if (ret < 0)
+		return ret;
 
 	ret = abx500_mask_and_set_register_interruptible(chip->dev,
 				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
@@ -64,25 +74,12 @@ static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	if (ret < 0)
 		dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
 							pwm->label, ret);
-	return ret;
-}
 
-static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	int ret;
-
-	ret = abx500_mask_and_set_register_interruptible(chip->dev,
-				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
-				1 << (chip->base - 1), 0);
-	if (ret < 0)
-		dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
-							pwm->label, ret);
+	return ret;
 }
 
 static const struct pwm_ops ab8500_pwm_ops = {
-	.config = ab8500_pwm_config,
-	.enable = ab8500_pwm_enable,
-	.disable = ab8500_pwm_disable,
+	.apply = ab8500_pwm_apply,
 	.owner = THIS_MODULE,
 };
 
@@ -101,7 +98,6 @@ static int ab8500_pwm_probe(struct platform_device *pdev)
 
 	ab8500->chip.dev = &pdev->dev;
 	ab8500->chip.ops = &ab8500_pwm_ops;
-	ab8500->chip.base = -1;
 	ab8500->chip.npwm = 1;
 
 	err = pwmchip_add(&ab8500->chip);
diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c
index dcbc0489dfd4..6ab597e54005 100644
--- a/drivers/pwm/pwm-atmel-hlcdc.c
+++ b/drivers/pwm/pwm-atmel-hlcdc.c
@@ -265,12 +265,11 @@ static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
 	chip->hlcdc = hlcdc;
 	chip->chip.ops = &atmel_hlcdc_pwm_ops;
 	chip->chip.dev = dev;
-	chip->chip.base = -1;
 	chip->chip.npwm = 1;
 	chip->chip.of_xlate = of_pwm_xlate_with_flags;
 	chip->chip.of_pwm_n_cells = 3;
 
-	ret = pwmchip_add_with_polarity(&chip->chip, PWM_POLARITY_INVERSED);
+	ret = pwmchip_add(&chip->chip);
 	if (ret) {
 		clk_disable_unprepare(hlcdc->periph_clk);
 		return ret;
diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c
index 5ccc3e7420e9..8451d3e846be 100644
--- a/drivers/pwm/pwm-atmel-tcb.c
+++ b/drivers/pwm/pwm-atmel-tcb.c
@@ -362,20 +362,37 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	tcbpwm->div = i;
 	tcbpwm->duty = duty;
 
-	/* If the PWM is enabled, call enable to apply the new conf */
-	if (pwm_is_enabled(pwm))
-		atmel_tcb_pwm_enable(chip, pwm);
-
 	return 0;
 }
 
+static int atmel_tcb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			       const struct pwm_state *state)
+{
+	int duty_cycle, period;
+	int ret;
+
+	/* This function only sets a flag in driver data */
+	atmel_tcb_pwm_set_polarity(chip, pwm, state->polarity);
+
+	if (!state->enabled) {
+		atmel_tcb_pwm_disable(chip, pwm);
+		return 0;
+	}
+
+	period = state->period < INT_MAX ? state->period : INT_MAX;
+	duty_cycle = state->duty_cycle < INT_MAX ? state->duty_cycle : INT_MAX;
+
+	ret = atmel_tcb_pwm_config(chip, pwm, duty_cycle, period);
+	if (ret)
+		return ret;
+
+	return atmel_tcb_pwm_enable(chip, pwm);
+}
+
 static const struct pwm_ops atmel_tcb_pwm_ops = {
 	.request = atmel_tcb_pwm_request,
 	.free = atmel_tcb_pwm_free,
-	.config = atmel_tcb_pwm_config,
-	.set_polarity = atmel_tcb_pwm_set_polarity,
-	.enable = atmel_tcb_pwm_enable,
-	.disable = atmel_tcb_pwm_disable,
+	.apply = atmel_tcb_pwm_apply,
 	.owner = THIS_MODULE,
 };
 
@@ -454,7 +471,6 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev)
 	tcbpwm->chip.ops = &atmel_tcb_pwm_ops;
 	tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags;
 	tcbpwm->chip.of_pwm_n_cells = 3;
-	tcbpwm->chip.base = -1;
 	tcbpwm->chip.npwm = NPWM;
 	tcbpwm->channel = channel;
 	tcbpwm->regmap = regmap;
@@ -491,14 +507,14 @@ static int atmel_tcb_pwm_remove(struct platform_device *pdev)
 	struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
 	int err;
 
-	clk_disable_unprepare(tcbpwm->slow_clk);
-	clk_put(tcbpwm->slow_clk);
-	clk_put(tcbpwm->clk);
-
 	err = pwmchip_remove(&tcbpwm->chip);
 	if (err < 0)
 		return err;
 
+	clk_disable_unprepare(tcbpwm->slow_clk);
+	clk_put(tcbpwm->slow_clk);
+	clk_put(tcbpwm->clk);
+
 	return 0;
 }
 
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index 5813339b597b..29b5ad03f715 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -124,6 +124,7 @@ static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip,
 }
 
 static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip,
+					     unsigned long clkrate,
 					     const struct pwm_state *state,
 					     unsigned long *cprd, u32 *pres)
 {
@@ -132,7 +133,7 @@ static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip,
 	int shift;
 
 	/* Calculate the period cycles and prescale value */
-	cycles *= clk_get_rate(atmel_pwm->clk);
+	cycles *= clkrate;
 	do_div(cycles, NSEC_PER_SEC);
 
 	/*
@@ -158,12 +159,14 @@ static int atmel_pwm_calculate_cprd_and_pres(struct pwm_chip *chip,
 }
 
 static void atmel_pwm_calculate_cdty(const struct pwm_state *state,
-				     unsigned long cprd, unsigned long *cdty)
+				     unsigned long clkrate, unsigned long cprd,
+				     u32 pres, unsigned long *cdty)
 {
 	unsigned long long cycles = state->duty_cycle;
 
-	cycles *= cprd;
-	do_div(cycles, state->period);
+	cycles *= clkrate;
+	do_div(cycles, NSEC_PER_SEC);
+	cycles >>= pres;
 	*cdty = cprd - cycles;
 }
 
@@ -244,17 +247,23 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	pwm_get_state(pwm, &cstate);
 
 	if (state->enabled) {
+		unsigned long clkrate = clk_get_rate(atmel_pwm->clk);
+
 		if (cstate.enabled &&
 		    cstate.polarity == state->polarity &&
 		    cstate.period == state->period) {
+			u32 cmr = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
+
 			cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
 						  atmel_pwm->data->regs.period);
-			atmel_pwm_calculate_cdty(state, cprd, &cdty);
+			pres = cmr & PWM_CMR_CPRE_MSK;
+
+			atmel_pwm_calculate_cdty(state, clkrate, cprd, pres, &cdty);
 			atmel_pwm_update_cdty(chip, pwm, cdty);
 			return 0;
 		}
 
-		ret = atmel_pwm_calculate_cprd_and_pres(chip, state, &cprd,
+		ret = atmel_pwm_calculate_cprd_and_pres(chip, clkrate, state, &cprd,
 							&pres);
 		if (ret) {
 			dev_err(chip->dev,
@@ -262,7 +271,7 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			return ret;
 		}
 
-		atmel_pwm_calculate_cdty(state, cprd, &cdty);
+		atmel_pwm_calculate_cdty(state, clkrate, cprd, pres, &cdty);
 
 		if (cstate.enabled) {
 			atmel_pwm_disable(chip, pwm, false);
@@ -319,7 +328,7 @@ static void atmel_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 
 		cdty = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
 					  atmel_pwm->data->regs.duty);
-		tmp = (u64)cdty * NSEC_PER_SEC;
+		tmp = (u64)(cprd - cdty) * NSEC_PER_SEC;
 		tmp <<= pres;
 		state->duty_cycle = DIV64_U64_ROUND_UP(tmp, rate);
 
@@ -429,7 +438,6 @@ static int atmel_pwm_probe(struct platform_device *pdev)
 	atmel_pwm->chip.ops = &atmel_pwm_ops;
 	atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
 	atmel_pwm->chip.of_pwm_n_cells = 3;
-	atmel_pwm->chip.base = -1;
 	atmel_pwm->chip.npwm = 4;
 
 	ret = pwmchip_add(&atmel_pwm->chip);
@@ -451,10 +459,12 @@ static int atmel_pwm_remove(struct platform_device *pdev)
 {
 	struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev);
 
+	pwmchip_remove(&atmel_pwm->chip);
+
 	clk_unprepare(atmel_pwm->clk);
 	mutex_destroy(&atmel_pwm->isr_lock);
 
-	return pwmchip_remove(&atmel_pwm->chip);
+	return 0;
 }
 
 static struct platform_driver atmel_pwm_driver = {
diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
index f4853c4a2d75..edd2ce1760ab 100644
--- a/drivers/pwm/pwm-bcm-iproc.c
+++ b/drivers/pwm/pwm-bcm-iproc.c
@@ -209,7 +209,6 @@ static int iproc_pwmc_probe(struct platform_device *pdev)
 
 	ip->chip.dev = &pdev->dev;
 	ip->chip.ops = &iproc_pwm_ops;
-	ip->chip.base = -1;
 	ip->chip.npwm = 4;
 	ip->chip.of_xlate = of_pwm_xlate_with_flags;
 	ip->chip.of_pwm_n_cells = 3;
@@ -254,9 +253,11 @@ static int iproc_pwmc_remove(struct platform_device *pdev)
 {
 	struct iproc_pwmc *ip = platform_get_drvdata(pdev);
 
+	pwmchip_remove(&ip->chip);
+
 	clk_disable_unprepare(ip->clk);
 
-	return pwmchip_remove(&ip->chip);
+	return 0;
 }
 
 static const struct of_device_id bcm_iproc_pwmc_dt[] = {
diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c
index 578b3621c97e..800b9edf2e71 100644
--- a/drivers/pwm/pwm-bcm-kona.c
+++ b/drivers/pwm/pwm-bcm-kona.c
@@ -271,7 +271,6 @@ static int kona_pwmc_probe(struct platform_device *pdev)
 
 	kp->chip.dev = &pdev->dev;
 	kp->chip.ops = &kona_pwm_ops;
-	kp->chip.base = -1;
 	kp->chip.npwm = 6;
 	kp->chip.of_xlate = of_pwm_xlate_with_flags;
 	kp->chip.of_pwm_n_cells = 3;
@@ -301,7 +300,7 @@ static int kona_pwmc_probe(struct platform_device *pdev)
 
 	clk_disable_unprepare(kp->clk);
 
-	ret = pwmchip_add_with_polarity(&kp->chip, PWM_POLARITY_INVERSED);
+	ret = pwmchip_add(&kp->chip);
 	if (ret < 0)
 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 
@@ -311,11 +310,6 @@ static int kona_pwmc_probe(struct platform_device *pdev)
 static int kona_pwmc_remove(struct platform_device *pdev)
 {
 	struct kona_pwmc *kp = platform_get_drvdata(pdev);
-	unsigned int chan;
-
-	for (chan = 0; chan < kp->chip.npwm; chan++)
-		if (pwm_is_enabled(&kp->chip.pwms[chan]))
-			clk_disable_unprepare(kp->clk);
 
 	return pwmchip_remove(&kp->chip);
 }
diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
index 6ff5f04b3e07..fc240d5b8121 100644
--- a/drivers/pwm/pwm-bcm2835.c
+++ b/drivers/pwm/pwm-bcm2835.c
@@ -64,8 +64,9 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
 	unsigned long rate = clk_get_rate(pc->clk);
-	unsigned long long period;
-	unsigned long scaler;
+	unsigned long long period_cycles;
+	u64 max_period;
+
 	u32 val;
 
 	if (!rate) {
@@ -73,18 +74,36 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		return -EINVAL;
 	}
 
-	scaler = DIV_ROUND_CLOSEST(NSEC_PER_SEC, rate);
+	/*
+	 * period_cycles must be a 32 bit value, so period * rate / NSEC_PER_SEC
+	 * must be <= U32_MAX. As U32_MAX * NSEC_PER_SEC < U64_MAX the
+	 * multiplication period * rate doesn't overflow.
+	 * To calculate the maximal possible period that guarantees the
+	 * above inequality:
+	 *
+	 *     round(period * rate / NSEC_PER_SEC) <= U32_MAX
+	 * <=> period * rate / NSEC_PER_SEC < U32_MAX + 0.5
+	 * <=> period * rate < (U32_MAX + 0.5) * NSEC_PER_SEC
+	 * <=> period < ((U32_MAX + 0.5) * NSEC_PER_SEC) / rate
+	 * <=> period < ((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate
+	 * <=> period <= ceil((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate) - 1
+	 */
+	max_period = DIV_ROUND_UP_ULL((u64)U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC / 2, rate) - 1;
+
+	if (state->period > max_period)
+		return -EINVAL;
+
 	/* set period */
-	period = DIV_ROUND_CLOSEST_ULL(state->period, scaler);
+	period_cycles = DIV_ROUND_CLOSEST_ULL(state->period * rate, NSEC_PER_SEC);
 
-	/* dont accept a period that is too small or has been truncated */
-	if ((period < PERIOD_MIN) || (period > U32_MAX))
+	/* don't accept a period that is too small */
+	if (period_cycles < PERIOD_MIN)
 		return -EINVAL;
 
-	writel(period, pc->base + PERIOD(pwm->hwpwm));
+	writel(period_cycles, pc->base + PERIOD(pwm->hwpwm));
 
 	/* set duty cycle */
-	val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, scaler);
+	val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * rate, NSEC_PER_SEC);
 	writel(val, pc->base + DUTY(pwm->hwpwm));
 
 	/* set polarity */
@@ -139,7 +158,6 @@ static int bcm2835_pwm_probe(struct platform_device *pdev)
 
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &bcm2835_pwm_ops;
-	pc->chip.base = -1;
 	pc->chip.npwm = 2;
 	pc->chip.of_xlate = of_pwm_xlate_with_flags;
 	pc->chip.of_pwm_n_cells = 3;
@@ -161,9 +179,11 @@ static int bcm2835_pwm_remove(struct platform_device *pdev)
 {