Merge tag 'pwm/for-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This set contains mostly fixes to existing drivers as well as cleanup
  of code that's not been in active use for a while"

* tag 'pwm/for-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (27 commits)
  acpi: lpss: call pwm_add_table() for BSW PWM device
  pwm: Try to load modules during pwm_get()
  pwm: Don't hold pwm_lookup_lock longer than necessary
  pwm: Make the PWM_POLARITY flag in DTB optional
  pwm: Print error messages with pr_err() instead of pr_debug()
  pwm: imx: Add polarity inversion support to i.MX's PWMv2
  pwm: imx: doc: Update imx-pwm.txt documentation entry
  pwm: imx: Remove redundant i.MX PWMv2 code
  pwm: imx: Provide atomic PWM support for i.MX PWMv2
  pwm: imx: Move PWMv2 wait for fifo slot code to a separate function
  pwm: imx: Move PWMv2 software reset code to a separate function
  pwm: imx: Rewrite v1 code to facilitate switch to atomic PWM
  pwm: imx: Add separate set of PWM ops for v1 and v2
  pwm: imx: Remove ipg clock and enable per clock when required
  pwm: lpss: Add Intel Gemini Lake PCI ID
  pwm: lpss: Do not export board infos for different PWM types
  pwm: lpss: Avoid reconfiguring while UPDATE bit is still enabled
  pwm: lpss: Switch to new atomic API
  pwm: lpss: Allow duty cycle to be 0
  pwm: lpss: Avoid potential overflow of base_unit
  ...

26 files changed, 462 insertions, 289 deletions

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 90d112a3063a..5edfd9c49044 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -21,6 +21,7 @@
 #include <linux/platform_data/x86/pmc_atom.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
+#include <linux/pwm.h>
 #include <linux/delay.h>
 
 #include "internal.h"
@@ -154,6 +155,18 @@ static void byt_i2c_setup(struct lpss_private_data *pdata)
 	writel(0, pdata->mmio_base + LPSS_I2C_ENABLE);
 }
 
+/* BSW PWM used for backlight control by the i915 driver */
+static struct pwm_lookup bsw_pwm_lookup[] = {
+	PWM_LOOKUP_WITH_MODULE("80862288:00", 0, "0000:00:02.0",
+			       "pwm_backlight", 0, PWM_POLARITY_NORMAL,
+			       "pwm-lpss-platform"),
+};
+
+static void bsw_pwm_setup(struct lpss_private_data *pdata)
+{
+	pwm_add_table(bsw_pwm_lookup, ARRAY_SIZE(bsw_pwm_lookup));
+}
+
 static const struct lpss_device_desc lpt_dev_desc = {
 	.flags = LPSS_CLK | LPSS_CLK_GATE | LPSS_CLK_DIVIDER | LPSS_LTR,
 	.prv_offset = 0x800,
@@ -191,6 +204,7 @@ static const struct lpss_device_desc byt_pwm_dev_desc = {
 
 static const struct lpss_device_desc bsw_pwm_dev_desc = {
 	.flags = LPSS_SAVE_CTX | LPSS_NO_D3_DELAY,
+	.setup = bsw_pwm_setup,
 };
 
 static const struct lpss_device_desc byt_uart_dev_desc = {
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index a9145aa7f36a..8d456dc6c5bf 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -29,7 +29,6 @@ struct led_pwm_data {
 	unsigned int		active_low;
 	unsigned int		period;
 	int			duty;
-	bool			can_sleep;
 };
 
 struct led_pwm_priv {
@@ -49,8 +48,8 @@ static void __led_pwm_set(struct led_pwm_data *led_dat)
 		pwm_enable(led_dat->pwm);
 }
 
-static void led_pwm_set(struct led_classdev *led_cdev,
-	enum led_brightness brightness)
+static int led_pwm_set(struct led_classdev *led_cdev,
+		       enum led_brightness brightness)
 {
 	struct led_pwm_data *led_dat =
 		container_of(led_cdev, struct led_pwm_data, cdev);
@@ -66,12 +65,7 @@ static void led_pwm_set(struct led_classdev *led_cdev,
 	led_dat->duty = duty;
 
 	__led_pwm_set(led_dat);
-}
 
-static int led_pwm_set_blocking(struct led_classdev *led_cdev,
-	enum led_brightness brightness)
-{
-	led_pwm_set(led_cdev, brightness);
 	return 0;
 }
 
@@ -112,11 +106,7 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
 		return ret;
 	}
 
-	led_data->can_sleep = pwm_can_sleep(led_data->pwm);
-	if (!led_data->can_sleep)
-		led_data->cdev.brightness_set = led_pwm_set;
-	else
-		led_data->cdev.brightness_set_blocking = led_pwm_set_blocking;
+	led_data->cdev.brightness_set_blocking = led_pwm_set;
 
 	/*
 	 * FIXME: pwm_apply_args() should be removed when switching to the
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 2d0cfaa6d84c..42e37c20b361 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -76,7 +76,9 @@ config PWM_ATMEL_TCB
 
 config PWM_BCM_IPROC
 	tristate "iProc PWM support"
-	depends on ARCH_BCM_IPROC
+	depends on ARCH_BCM_IPROC || COMPILE_TEST
+	depends on COMMON_CLK
+	default ARCH_BCM_IPROC
 	help
 	  Generic PWM framework driver for Broadcom iProc PWM block. This
 	  block is used in Broadcom iProc SoC's.
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 172ef8245811..a0860b30bd93 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -137,9 +137,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
 
+	/* check, whether the driver supports a third cell for flags */
 	if (pc->of_pwm_n_cells < 3)
 		return ERR_PTR(-EINVAL);
 
+	/* flags in the third cell are optional */
+	if (args->args_count < 2)
+		return ERR_PTR(-EINVAL);
+
 	if (args->args[0] >= pc->npwm)
 		return ERR_PTR(-EINVAL);
 
@@ -148,11 +153,10 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 		return pwm;
 
 	pwm->args.period = args->args[1];
+	pwm->args.polarity = PWM_POLARITY_NORMAL;
 
-	if (args->args[2] & PWM_POLARITY_INVERTED)
+	if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
 		pwm->args.polarity = PWM_POLARITY_INVERSED;
-	else
-		pwm->args.polarity = PWM_POLARITY_NORMAL;
 
 	return pwm;
 }
@@ -163,9 +167,14 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
 
+	/* sanity check driver support */
 	if (pc->of_pwm_n_cells < 2)
 		return ERR_PTR(-EINVAL);
 
+	/* all cells are required */
+	if (args->args_count != pc->of_pwm_n_cells)
+		return ERR_PTR(-EINVAL);
+
 	if (args->args[0] >= pc->npwm)
 		return ERR_PTR(-EINVAL);
 
@@ -663,24 +672,17 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
 					 &args);
 	if (err) {
-		pr_debug("%s(): can't parse \"pwms\" property\n", __func__);
+		pr_err("%s(): can't parse \"pwms\" property\n", __func__);
 		return ERR_PTR(err);
 	}
 
 	pc = of_node_to_pwmchip(args.np);
 	if (IS_ERR(pc)) {
-		pr_debug("%s(): PWM chip not found\n", __func__);
+		pr_err("%s(): PWM chip not found\n", __func__);
 		pwm = ERR_CAST(pc);
 		goto put;
 	}
 
-	if (args.args_count != pc->of_pwm_n_cells) {
-		pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
-			 args.np->full_name);
-		pwm = ERR_PTR(-EINVAL);
-		goto put;
-	}
-
 	pwm = pc->of_xlate(pc, &args);
 	if (IS_ERR(pwm))
 		goto put;
@@ -757,12 +759,13 @@ void pwm_remove_table(struct pwm_lookup *table, size_t num)
  */
 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 {
-	struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
 	const char *dev_id = dev ? dev_name(dev) : NULL;
-	struct pwm_chip *chip = NULL;
+	struct pwm_device *pwm;
+	struct pwm_chip *chip;
 	unsigned int best = 0;
 	struct pwm_lookup *p, *chosen = NULL;
 	unsigned int match;
+	int err;
 
 	/* look up via DT first */
 	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
@@ -817,24 +820,35 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 		}
 	}
 
-	if (!chosen) {
-		pwm = ERR_PTR(-ENODEV);
-		goto out;
-	}
+	mutex_unlock(&pwm_lookup_lock);
+
+	if (!chosen)
+		return ERR_PTR(-ENODEV);
 
 	chip = pwmchip_find_by_name(chosen->provider);
+
+	/*
+	 * If the lookup entry specifies a module, load the module and retry
+	 * the PWM chip lookup. This can be used to work around driver load
+	 * ordering issues if driver's can't be made to properly support the
+	 * deferred probe mechanism.
+	 */
+	if (!chip && chosen->module) {
+		err = request_module(chosen->module);
+		if (err == 0)
+			chip = pwmchip_find_by_name(chosen->provider);
+	}
+
 	if (!chip)
-		goto out;
+		return ERR_PTR(-EPROBE_DEFER);
 
 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
 	if (IS_ERR(pwm))
-		goto out;
+		return pwm;
 
 	pwm->args.period = chosen->period;
 	pwm->args.polarity = chosen->polarity;
 
-out:
-	mutex_unlock(&pwm_lookup_lock);
 	return pwm;
 }
 EXPORT_SYMBOL_GPL(pwm_get);
@@ -960,18 +974,6 @@ void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 }
 EXPORT_SYMBOL_GPL(devm_pwm_put);
 
-/**
-  * pwm_can_sleep() - report whether PWM access will sleep
-  * @pwm: PWM device
-  *
-  * Returns: True if accessing the PWM can sleep, false otherwise.
-  */
-bool pwm_can_sleep(struct pwm_device *pwm)
-{
-	return true;
-}
-EXPORT_SYMBOL_GPL(pwm_can_sleep);
-
 #ifdef CONFIG_DEBUG_FS
 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 {
diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c
index 14fc011faa32..999187277ea5 100644
--- a/drivers/pwm/pwm-atmel-hlcdc.c
+++ b/drivers/pwm/pwm-atmel-hlcdc.c
@@ -270,7 +270,6 @@ static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
 	chip->chip.npwm = 1;
 	chip->chip.of_xlate = of_pwm_xlate_with_flags;
 	chip->chip.of_pwm_n_cells = 3;
-	chip->chip.can_sleep = 1;
 
 	ret = pwmchip_add_with_polarity(&chip->chip, PWM_POLARITY_INVERSED);
 	if (ret) {
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index e6b8b1b7e6ba..67a7023be5c2 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -385,7 +385,6 @@ static int atmel_pwm_probe(struct platform_device *pdev)
 
 	atmel_pwm->chip.base = -1;
 	atmel_pwm->chip.npwm = 4;
-	atmel_pwm->chip.can_sleep = true;
 	atmel_pwm->config = data->config;
 	atmel_pwm->updated_pwms = 0;
 	mutex_init(&atmel_pwm->isr_lock);
diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c
index c63418322023..09a95aeb3a70 100644
--- a/drivers/pwm/pwm-bcm-kona.c
+++ b/drivers/pwm/pwm-bcm-kona.c
@@ -276,7 +276,6 @@ static int kona_pwmc_probe(struct platform_device *pdev)
 	kp->chip.npwm = 6;
 	kp->chip.of_xlate = of_pwm_xlate_with_flags;
 	kp->chip.of_pwm_n_cells = 3;
-	kp->chip.can_sleep = true;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	kp->base = devm_ioremap_resource(&pdev->dev, res);
diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c
index 01339c152ab0..771859aca4be 100644
--- a/drivers/pwm/pwm-berlin.c
+++ b/drivers/pwm/pwm-berlin.c
@@ -206,7 +206,6 @@ static int berlin_pwm_probe(struct platform_device *pdev)
 	pwm->chip.ops = &berlin_pwm_ops;
 	pwm->chip.base = -1;
 	pwm->chip.npwm = 4;
-	pwm->chip.can_sleep = true;
 	pwm->chip.of_xlate = of_pwm_xlate_with_flags;
 	pwm->chip.of_pwm_n_cells = 3;
 
diff --git a/drivers/pwm/pwm-bfin.c b/drivers/pwm/pwm-bfin.c
index 7631ef194de7..d2ed0a2a18e8 100644
--- a/drivers/pwm/pwm-bfin.c
+++ b/drivers/pwm/pwm-bfin.c
@@ -103,7 +103,7 @@ static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	disable_gptimer(priv->pin);
 }
 
-static struct pwm_ops bfin_pwm_ops = {
+static const struct pwm_ops bfin_pwm_ops = {
 	.request = bfin_pwm_request,
 	.free = bfin_pwm_free,
 	.config = bfin_pwm_config,
diff --git a/drivers/pwm/pwm-brcmstb.c b/drivers/pwm/pwm-brcmstb.c
index 5d5adee16886..8063cffa1c96 100644
--- a/drivers/pwm/pwm-brcmstb.c
+++ b/drivers/pwm/pwm-brcmstb.c
@@ -270,7 +270,6 @@ static int brcmstb_pwm_probe(struct platform_device *pdev)
 	p->chip.ops = &brcmstb_pwm_ops;
 	p->chip.base = -1;
 	p->chip.npwm = 2;
-	p->chip.can_sleep = true;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	p->base = devm_ioremap_resource(&pdev->dev, res);
diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c
index fad968eb75f6..557b4ea16796 100644
--- a/drivers/pwm/pwm-fsl-ftm.c
+++ b/drivers/pwm/pwm-fsl-ftm.c
@@ -446,7 +446,6 @@ static int fsl_pwm_probe(struct platform_device *pdev)
 	fpc->chip.of_pwm_n_cells = 3;
 	fpc->chip.base = -1;
 	fpc->chip.npwm = 8;
-	fpc->chip.can_sleep = true;
 
 	ret = pwmchip_add(&fpc->chip);
 	if (ret < 0) {
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index d600fd5cd4ba..2ba5c3a398ff 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -38,6 +38,7 @@
 #define MX3_PWMCR_DOZEEN		(1 << 24)
 #define MX3_PWMCR_WAITEN		(1 << 23)
 #define MX3_PWMCR_DBGEN			(1 << 22)
+#define MX3_PWMCR_POUTC			(1 << 18)
 #define MX3_PWMCR_CLKSRC_IPG_HIGH	(2 << 16)
 #define MX3_PWMCR_CLKSRC_IPG		(1 << 16)
 #define MX3_PWMCR_SWR			(1 << 3)
@@ -49,15 +50,10 @@
 
 struct imx_chip {
 	struct clk	*clk_per;
-	struct clk	*clk_ipg;
 
 	void __iomem	*mmio_base;
 
 	struct pwm_chip	chip;
-
-	int (*config)(struct pwm_chip *chip,
-		struct pwm_device *pwm, int duty_ns, int period_ns);
-	void (*set_enable)(struct pwm_chip *chip, bool enable);
 };
 
 #define to_imx_chip(chip)	container_of(chip, struct imx_chip, chip)
@@ -91,176 +87,170 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
 	return 0;
 }
 
-static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
+static int imx_pwm_enable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct imx_chip *imx = to_imx_chip(chip);
 	u32 val;
+	int ret;
 
-	val = readl(imx->mmio_base + MX1_PWMC);
-
-	if (enable)
-		val |= MX1_PWMC_EN;
-	else
-		val &= ~MX1_PWMC_EN;
+	ret = clk_prepare_enable(imx->clk_per);
+	if (ret < 0)
+		return ret;
 
+	val = readl(imx->mmio_base + MX1_PWMC);
+	val |= MX1_PWMC_EN;
 	writel(val, imx->mmio_base + MX1_PWMC);
-}
-
-static int imx_pwm_config_v2(struct pwm_chip *chip,
-		struct pwm_device *pwm, int duty_ns, int period_ns)
-{
-	struct imx_chip *imx = to_imx_chip(chip);
-	struct device *dev = chip->dev;
-	unsigned long long c;
-	unsigned long period_cycles, duty_cycles, prescale;
-	unsigned int period_ms;
-	bool enable = pwm_is_enabled(pwm);
-	int wait_count = 0, fifoav;
-	u32 cr, sr;
-
-	/*
-	 * i.MX PWMv2 has a 4-word sample FIFO.
-	 * In order to avoid FIFO overflow issue, we do software reset
-	 * to clear all sample FIFO if the controller is disabled or
-	 * wait for a full PWM cycle to get a relinquished FIFO slot
-	 * when the controller is enabled and the FIFO is fully loaded.
-	 */
-	if (enable) {
-		sr = readl(imx->mmio_base + MX3_PWMSR);
-		fifoav = sr & MX3_PWMSR_FIFOAV_MASK;
-		if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
-			period_ms = DIV_ROUND_UP(pwm_get_period(pwm),
-						 NSEC_PER_MSEC);
-			msleep(period_ms);
-
-			sr = readl(imx->mmio_base + MX3_PWMSR);
-			if (fifoav == (sr & MX3_PWMSR_FIFOAV_MASK))
-				dev_warn(dev, "there is no free FIFO slot\n");
-		}
-	} else {
-		writel(MX3_PWMCR_SWR, imx->mmio_base + MX3_PWMCR);
-		do {
-			usleep_range(200, 1000);
-			cr = readl(imx->mmio_base + MX3_PWMCR);
-		} while ((cr & MX3_PWMCR_SWR) &&
-			 (wait_count++ < MX3_PWM_SWR_LOOP));
-
-		if (cr & MX3_PWMCR_SWR)
-			dev_warn(dev, "software reset timeout\n");
-	}
-
-	c = clk_get_rate(imx->clk_per);
-	c = c * period_ns;
-	do_div(c, 1000000000);
-	period_cycles = c;
-
-	prescale = period_cycles / 0x10000 + 1;
-
-	period_cycles /= prescale;
-	c = (unsigned long long)period_cycles * duty_ns;
-	do_div(c, period_ns);
-	duty_cycles = c;
-
-	/*
-	 * according to imx pwm RM, the real period value should be
-	 * PERIOD value in PWMPR plus 2.
-	 */
-	if (period_cycles > 2)
-		period_cycles -= 2;
-	else
-		period_cycles = 0;
-
-	writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
-	writel(period_cycles, imx->mmio_base + MX3_PWMPR);
-
-	cr = MX3_PWMCR_PRESCALER(prescale) |
-		MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
-		MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH;
-
-	if (enable)
-		cr |= MX3_PWMCR_EN;
-
-	writel(cr, imx->mmio_base + MX3_PWMCR);
 
 	return 0;
 }
 
-static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable)
+static void imx_pwm_disable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct imx_chip *imx = to_imx_chip(chip);
 	u32 val;
 
-	val = readl(imx->mmio_base + MX3_PWMCR);
-
-	if (enable)
-		val |= MX3_PWMCR_EN;
-	else
-		val &= ~MX3_PWMCR_EN;
+	val = readl(imx->mmio_base + MX1_PWMC);
+	val &= ~MX1_PWMC_EN;
+	writel(val, imx->mmio_base + MX1_PWMC);
 
-	writel(val, imx->mmio_base + MX3_PWMCR);
+	clk_disable_unprepare(imx->clk_per);
 }
 
-static int imx_pwm_config(struct pwm_chip *chip,
-		struct pwm_device *pwm, int duty_ns, int period_ns)
+static void imx_pwm_sw_reset(struct pwm_chip *chip)
 {
 	struct imx_chip *imx = to_imx_chip(chip);
-	int ret;
-
-	ret = clk_prepare_enable(imx->clk_ipg);
-	if (ret)
-		return ret;
+	struct device *dev = chip->dev;
+	int wait_count = 0;
+	u32 cr;
+
+	writel(MX3_PWMCR_SWR, imx->mmio_base + MX3_PWMCR);
+	do {
+		usleep_range(200, 1000);
+		cr = readl(imx->mmio_base + MX3_PWMCR);
+	} while ((cr & MX3_PWMCR_SWR) &&
+		 (wait_count++ < MX3_PWM_SWR_LOOP));
+
+	if (cr & MX3_PWMCR_SWR)
+		dev_warn(dev, "software reset timeout\n");
+}
 
-	ret = imx->config(chip, pwm, duty_ns, period_ns);
+static void imx_pwm_wait_fifo_slot(struct pwm_chip *chip,
+				   struct pwm_device *pwm)
+{
+	struct imx_chip *imx = to_imx_chip(chip);
+	struct device *dev = chip->dev;
+	unsigned int period_ms;
+	int fifoav;
+	u32 sr;
 
-	clk_disable_unprepare(imx->clk_ipg);
+	sr = readl(imx->mmio_base + MX3_PWMSR);
+	fifoav = sr & MX3_PWMSR_FIFOAV_MASK;
+	if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
+		period_ms = DIV_ROUND_UP(pwm_get_period(pwm),
+					 NSEC_PER_MSEC);
+		msleep(period_ms);
 
-	return ret;
+		sr = readl(imx->mmio_base + MX3_PWMSR);
+		if (fifoav == (sr & MX3_PWMSR_FIFOAV_MASK))
+			dev_warn(dev, "there is no free FIFO slot\n");
+	}
 }
 
-static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm,
+			    struct pwm_state *state)
 {
+	unsigned long period_cycles, duty_cycles, prescale;
 	struct imx_chip *imx = to_imx_chip(chip);
+	struct pwm_state cstate;
+	unsigned long long c;
 	int ret;
+	u32 cr;
+
+	pwm_get_state(pwm, &cstate);
+
+	if (state->enabled) {
+		c = clk_get_rate(imx->clk_per);
+		c *= state->period;
+
+		do_div(c, 1000000000);
+		period_cycles = c;
+
+		prescale = period_cycles / 0x10000 + 1;
+
+		period_cycles /= prescale;
+		c = (unsigned long long)period_cycles * state->duty_cycle;
+		do_div(c, state->period);
+		duty_cycles = c;
+
+		/*
+		 * according to imx pwm RM, the real period value should be
+		 * PERIOD value in PWMPR plus 2.
+		 */
+		if (period_cycles > 2)
+			period_cycles -= 2;
+		else
+			period_cycles = 0;
+
+		/*
+		 * Wait for a free FIFO slot if the PWM is already enabled, and
+		 * flush the FIFO if the PWM was disabled and is about to be
+		 * enabled.
+		 */
+		if (cstate.enabled) {
+			imx_pwm_wait_fifo_slot(chip, pwm);
+		} else {
+			ret = clk_prepare_enable(imx->clk_per);
+			if (ret)
+				return ret;
+
+			imx_pwm_sw_reset(chip);
+		}
 
-	ret = clk_prepare_enable(imx->clk_per);
-	if (ret)
-		return ret;
+		writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
+		writel(period_cycles, imx->mmio_base + MX3_PWMPR);
 
-	imx->set_enable(chip, true);
+		cr = MX3_PWMCR_PRESCALER(prescale) |
+		     MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
+		     MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH |
+		     MX3_PWMCR_EN;
 
-	return 0;
-}
+		if (state->polarity == PWM_POLARITY_INVERSED)
+			cr |= MX3_PWMCR_POUTC;
 
-static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct imx_chip *imx = to_imx_chip(chip);
+		writel(cr, imx->mmio_base + MX3_PWMCR);
+	} else if (cstate.enabled) {
+		writel(0, imx->mmio_base + MX3_PWMCR);
 
-	imx->set_enable(chip, false);
+		clk_disable_unprepare(imx->clk_per);
+	}
 
-	clk_disable_unprepare(imx->clk_per);
+	return 0;
 }
 
-static struct pwm_ops imx_pwm_ops = {
-	.enable = imx_pwm_enable,
-	.disable = imx_pwm_disable,
-	.config = imx_pwm_config,
+static const struct pwm_ops imx_pwm_ops_v1 = {
+	.enable = imx_pwm_enable_v1,
+	.disable = imx_pwm_disable_v1,
+	.config = imx_pwm_config_v1,
+	.owner = THIS_MODULE,
+};
+
+static const struct pwm_ops imx_pwm_ops_v2 = {
+	.apply = imx_pwm_apply_v2,
 	.owner = THIS_MODULE,
 };
 
 struct imx_pwm_data {
-	int (*config)(struct pwm_chip *chip,
-		struct pwm_device *pwm, int duty_ns, int period_ns);
-	void (*set_enable)(struct pwm_chip *chip, bool enable);
+	bool polarity_supported;
+	const struct pwm_ops *ops;
 };
 
 static struct imx_pwm_data imx_pwm_data_v1 = {
-	.config = imx_pwm_config_v1,
-	.set_enable = imx_pwm_set_enable_v1,
+	.ops = &imx_pwm_ops_v1,
 };
 
 static struct imx_pwm_data imx_pwm_data_v2 = {
-	.config = imx_pwm_config_v2,
-	.set_enable = imx_pwm_set_enable_v2,
+	.polarity_supported = true,
+	.ops = &imx_pwm_ops_v2,
 };
 
 static const struct of_device_id imx_pwm_dt_ids[] = {
@@ -282,6 +272,8 @@ static int imx_pwm_probe(struct platform_device *pdev)
 	if (!of_id)
 		return -ENODEV;
 
+	data = of_id->data;
+
 	imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
 	if (imx == NULL)
 		return -ENOMEM;
@@ -293,28 +285,22 @@ static int imx_pwm_probe(struct platform_device *pdev)
 		return PTR_ERR(imx->clk_per);
 	}
 
-	imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
-	if (IS_ERR(imx->clk_ipg)) {
-		dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
-				PTR_ERR(imx->clk_ipg));
-		return PTR_ERR(imx->clk_ipg);
-	}
-
-	imx->chip.ops = &imx_pwm_ops;
+	imx->chip.ops = data->ops;
 	imx->chip.dev = &pdev->dev;
 	imx->chip.base = -1;
 	imx->chip.npwm = 1;
-	imx->chip.can_sleep = true;
+
+	if (data->polarity_supported) {
+		dev_dbg(&pdev->dev, "PWM supports output inversion\n");
+		imx->chip.of_xlate = of_pwm_xlate_with_flags;
+		imx->chip.of_pwm_n_cells = 3;
+	}
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
 	if (IS_ERR(imx->mmio_base))
 		return PTR_ERR(imx->mmio_base);
 
-	data = of_id->data;
-	imx->config = data->config;
-	imx->set_enable = data->set_enable;
-
 	ret = pwmchip_add(&imx->chip);
 	if (ret < 0)
 		return ret;
diff --git a/drivers/pwm/pwm-lp3943.c b/drivers/pwm/pwm-lp3943.c
index 872ea76a4f19..52584e9962ed 100644
--- a/drivers/pwm/pwm-lp3943.c
+++ b/drivers/pwm/pwm-lp3943.c
@@ -278,7 +278,6 @@ static int lp3943_pwm_probe(struct platform_device *pdev)
 	lp3943_pwm->chip.dev = &pdev->dev;
 	lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 	lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
-	lp3943_pwm->chip.can_sleep = true;
 
 	platform_set_drvdata(pdev, lp3943_pwm);
 
diff --git a/drivers/pwm/pwm-lpss-pci.c b/drivers/pwm/pwm-lpss-pci.c
index 3622f093490e..053088b9b66e 100644
--- a/drivers/pwm/pwm-lpss-pci.c
+++ b/drivers/pwm/pwm-lpss-pci.c
@@ -17,6 +17,27 @@
 
 #include "pwm-lpss.h"
 
+/* BayTrail */
+static const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
+	.clk_rate = 25000000,
+	.npwm = 1,
+	.base_unit_bits = 16,
+};
+
+/* Braswell */
+static const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
+	.clk_rate = 19200000,
+	.npwm = 1,
+	.base_unit_bits = 16,
+};
+
+/* Broxton */
+static const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
+	.clk_rate = 19200000,
+	.npwm = 4,
+	.base_unit_bits = 22,
+};
+
 static int pwm_lpss_probe_pci(struct pci_dev *pdev,
 			      const struct pci_device_id *id)
 {
@@ -80,6 +101,7 @@ static const struct pci_device_id pwm_lpss_pci_ids[] = {
 	{ PCI_VDEVICE(INTEL, 0x1ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x2288), (unsigned long)&pwm_lpss_bsw_info},
 	{ PCI_VDEVICE(INTEL, 0x2289), (unsigned long)&pwm_lpss_bsw_info},
+	{ PCI_VDEVICE(INTEL, 0x31c8), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x5ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ },
 };
diff --git a/drivers/pwm/pwm-lpss-platform.c b/drivers/pwm/pwm-lpss-platform.c
index 54433fc6d1a4..b22b6fdadb9a 100644
--- a/drivers/pwm/pwm-lpss-platform.c
+++ b/drivers/pwm/pwm-lpss-platform.c
@@ -18,6 +18,27 @@
 
 #include "pwm-lpss.h"
 
+/* BayTrail */
+static const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
+	.clk_rate = 25000000,
+	.npwm = 1,
+	.base_unit_bits = 16,
+};
+
+/* Braswell */
+static const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
+	.clk_rate = 19200000,
+	.npwm = 1,
+	.base_unit_bits = 16,
+};
+
+/* Broxton */
+static const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
+	.clk_rate = 19200000,
+	.npwm = 4,
+	.base_unit_bits = 22,
+};
+
 static int pwm_lpss_probe_platform(struct platform_device *pdev)
 {
 	const struct pwm_lpss_boardinfo *info;
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 72c0bce5a75c..689d2c1cbead 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -15,6 +15,7 @@
 
 #include <linux/delay.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
@@ -37,30 +38,6 @@ struct pwm_lpss_chip {
 	const struct pwm_lpss_boardinfo *info;
 };
 
-/* BayTrail */
-const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
-	.clk_rate = 25000000,
-	.npwm = 1,
-	.base_unit_bits = 16,
-};
-EXPORT_SYMBOL_GPL(pwm_lpss_byt_info);
-
-/* Braswell */
-const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
-	.clk_rate = 19200000,
-	.npwm = 1,
-	.base_unit_bits = 16,
-};
-EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info);
-
-/* Broxton */
-const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
-	.clk_rate = 19200000,
-	.npwm = 4,
-	.base_unit_bits = 22,
-};
-EXPORT_SYMBOL_GPL(pwm_lpss_bxt_info);
-
 static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
 {
 	return container_of(chip, struct pwm_lpss_chip, chip);
@@ -80,17 +57,42 @@ static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
 	writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
 }
 
-static void pwm_lpss_update(struct pwm_device *pwm)
+static int pwm_lpss_update(struct pwm_device *pwm)
 {
+	struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip);
+	const void __iomem *addr = lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM;
+	const unsigned int ms = 500 * USEC_PER_MSEC;
+	u32 val;
+	int err;
+
 	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
-	/* Give it some time to propagate */
-	usleep_range(10, 50);
+
+	/*
+	 * PWM Configuration register has SW_UPDATE bit that is set when a new
+	 * configuration is written to the register. The bit is automatically
+	 * cleared at the start of the next output cycle by the IP block.
+	 *
+	 * If one writes a new configuration to the register while it still has
+	 * the bit enabled, PWM may freeze. That is, while one can still write
+	 * to the register, it won't have an effect. Thus, we try to sleep long
+	 * enough that the bit gets cleared and make sure the bit is not
+	 * enabled while we update the configuration.
+	 */
+	err = readl_poll_timeout(addr, val, !(val & PWM_SW_UPDATE), 40, ms);
+	if (err)
+		dev_err(pwm->chip->dev, "PWM_SW_UPDATE was not cleared\n");
+
+	return err;
 }
 
-static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			   int duty_ns, int period_ns)
+static inline int pwm_lpss_is_updating(struct pwm_device *pwm)
+{
+	return (pwm_lpss_read(pwm) & PWM_SW_UPDATE) ? -EBUSY : 0;
+}
+
+static void pwm_lpss_prepare(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm,
+			     int duty_ns, int period_ns)
 {
-	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
 	unsigned long long on_time_div;
 	unsigned long c = lpwm->info->clk_rate, base_unit_range;
 	unsigned long long base_unit, freq = NSEC_PER_SEC;
@@ -102,62 +104,62 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * The equation is:
 	 * base_unit = round(base_unit_range * freq / c)
 	 */
-	base_unit_range = BIT(lpwm->info->base_unit_bits);
+	base_unit_range = BIT(lpwm->info->base_unit_bits) - 1;
 	freq *= base_unit_range;
 
 	base_unit = DIV_ROUND_CLOSEST_ULL(freq, c);
 
-	if (duty_ns <= 0)
-		duty_ns = 1;
 	on_time_div = 255ULL * duty_ns;
 	do_div(on_time_div, period_ns);
 	on_time_div = 255ULL - on_time_div;
 
-	pm_runtime_get_sync(chip->dev);
-
 	ctrl = pwm_lpss_read(pwm);
 	ctrl &= ~PWM_ON_TIME_DIV_MASK;
-	ctrl &= ~((base_unit_range - 1) << PWM_BASE_UNIT_SHIFT);
-	base_unit &= (base_unit_range - 1);
+	ctrl &= ~(base_unit_range << PWM_BASE_UNIT_SHIFT);
+	base_unit &= base_unit_range;
 	ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
 	ctrl |= on_time_div;
 	pwm_lpss_write(pwm, ctrl);
-
-	/*
-	 * If the PWM is already enabled we need to notify the hardware
-	 * about the change by setting PWM_SW_UPDATE.
-	 */
-	if (pwm_is_enabled(pwm))
-		pwm_lpss_update(pwm);
-
-	pm_runtime_put(chip->dev);
-
-	return 0;
 }
 
-static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			  struct pwm_state *state)
 {
-	pm_runtime_get_sync(chip->dev);
+	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
+	int ret;
 
-	/*
-	 * Hardware must first see PWM_SW_UPDATE before the PWM can be
-	 * enabled.
-	 */
-	pwm_lpss_update(pwm);
-	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
-	return 0;
-}
+	if (state->enabled) {
+		if (!pwm_is_enabled(pwm)) {
+			pm_runtime_get_sync(chip->dev);
+			ret = pwm_lpss_is_updating(pwm);
+			if (ret) {
+				pm_runtime_put(chip->dev);
+				return ret;
+			}
+			pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
+			ret = pwm_lpss_update(pwm);
+			if (ret) {
+				pm_runtime_put(chip->dev);
+				return ret;
+			}
+			pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
+		} else {
+			ret = pwm_lpss_is_updating(pwm);
+			if (ret)
+				return ret;
+			pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
+			return pwm_lpss_update(pwm);
+		}
+	} else if (pwm_is_enabled(pwm)) {
+		pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
+		pm_runtime_put(chip->dev);
+	}
 
-static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
-	pm_runtime_put(chip->dev);
+	return 0;
 }
 
 static const struct pwm_ops pwm_lpss_ops = {
-	.config = pwm_lpss_config,
-	.enable = pwm_lpss_enable,
-	.disable = pwm_lpss_disable,
+	.apply = pwm_lpss_apply,
 	.owner = THIS_MODULE,
 };
 
diff --git a/drivers/pwm/pwm-lpss.h b/drivers/pwm/pwm-lpss.h
index 04766e0d41aa..c94cd7c2695d 100644
--- a/drivers/pwm/pwm-lpss.h
+++ b/drivers/pwm/pwm-lpss.h
@@ -24,10 +24,6 @@ struct pwm_lpss_boardinfo {
 	unsigned long base_unit_bits;
 };
 
-extern const struct pwm_lpss_boardinfo pwm_lpss_byt_info;
-extern const struct pwm_lpss_boardinfo pwm_lpss_bsw_info;
-extern const struct pwm_lpss_boardinfo pwm_lpss_bxt_info;
-
 struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
 				     const struct pwm_lpss_boardinfo *info);
 int pwm_lpss_remove(struct pwm_lpss_chip *lpwm);
diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c
index 9a596324ebef..a6017ad9926c 100644
--- a/drivers/pwm/pwm-mxs.c
+++ b/drivers/pwm/pwm-mxs.c
@@ -151,7 +151,7 @@ static int mxs_pwm_probe(struct platform_device *pdev)
 	mxs->chip.dev = &pdev->dev;
 	mxs->chip.ops = &mxs_pwm_ops;
 	mxs->chip.base = -1;
-	mxs->chip.can_sleep = true;
+
 	ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c
index 117fccf7934a..0cfb3571a732 100644
--- a/drivers/pwm/pwm-pca9685.c
+++ b/drivers/pwm/pwm-pca9685.c
@@ -20,8 +20,10 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/gpio/driver.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/pwm.h>
@@ -65,7 +67,6 @@
 #define PCA9685_MAXCHAN		0x10
 
 #define LED_FULL		(1 << 4)
-#define MODE1_RESTART		(1 << 7)
 #define MODE1_SLEEP		(1 << 4)
 #define MODE2_INVRT		(1 << 4)
 #define MODE2_OUTDRV		(1 << 2)
@@ -81,6 +82,10 @@ struct pca9685 {
 	int active_cnt;
 	int duty_ns;
 	int period_ns;
+#if IS_ENABLED(CONFIG_GPIOLIB)
+	struct mutex lock;
+	struct gpio_chip gpio;
+#endif
 };
 
 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
@@ -88,6 +93,151 @@ static inline struct pca9685 *to_pca(struct pwm_chip *chip)
 	return container_of(chip, struct pca9685, chip);
 }
 
+#if IS_ENABLED(CONFIG_GPIOLIB)
+static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
+{
+	struct pca9685 *pca = gpiochip_get_data(gpio);
+	struct pwm_device *pwm;
+
+	mutex_lock(&pca->lock);
+
+	pwm = &pca->chip.pwms[offset];
+
+	if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
+		mutex_unlock(&pca->lock);
+		return -EBUSY;
+	}
+
+	pwm_set_chip_data(pwm, (void *)1);
+
+	mutex_unlock(&pca->lock);
+	return 0;
+}
+
+static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
+{
+	struct pca9685 *pca = gpiochip_get_data(gpio);
+	struct pwm_device *pwm;
+
+	mutex_lock(&pca->lock);
+	pwm = &pca->chip.pwms[offset];
+	pwm_set_chip_data(pwm, NULL);
+	mutex_unlock(&pca->lock);
+}
+
+static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
+{
+	bool is_gpio = false;
+
+	mutex_lock(&pca->lock);
+
+	if (pwm->hwpwm >= PCA9685_MAXCHAN) {
+		unsigned int i;
+
+		/*
+		 * Check if any of the GPIOs are requested and in that case
+		 * prevent using the "all LEDs" channel.
+		 */
+		for (i = 0; i < pca->gpio.ngpio; i++)
+			if (gpiochip_is_requested(&pca->gpio, i)) {
+				is_gpio = true;
+				break;
+			}
+	} else if (pwm_get_chip_data(pwm)) {
+		is_gpio = true;
+	}
+
+	mutex_unlock(&pca->lock);
+	return is_gpio;
+}
+
+static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
+{
+	struct pca9685 *pca = gpiochip_get_data(gpio);
+	struct pwm_device *pwm = &pca->chip.pwms[offset];
+	unsigned int value;
+
+	regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
+
+	return value & LED_FULL;
+}
+
+static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
+				 int value)
+{
+	struct pca9685 *pca = gpiochip_get_data(gpio);
+	struct pwm_device *pwm = &pca->chip.pwms[offset];
+	unsigned int on = value ? LED_FULL : 0;
+
+	/* Clear both OFF registers */
+	regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
+	regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
+
+	/* Set the full ON bit */
+	regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
+}
+
+static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
+					  unsigned int offset)
+{
+	/* Always out */
+	return 0;
+}
+
+static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
+					    unsigned int offset)
+{
+	return -EINVAL;
+}
+
+static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
+					     unsigned int offset, int value)
+{
+	pca9685_pwm_gpio_set(gpio, offset, value);
+
+	return 0;
+}
+
+/*
+ * The PCA9685 has a bit for turning the PWM output full off or on. Some
+ * boards like Intel Galileo actually uses these as normal GPIOs so we
+ * expose a GPIO chip here which can exclusively take over the underlying
+ * PWM channel.
+ */
+static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
+{
+	struct device *dev = pca->chip.dev;
+
+	mutex_init(&pca->lock);
+
+	pca->gpio.label = dev_name(dev);
+	pca->gpio.parent = dev;
+	pca->gpio.request = pca9685_pwm_gpio_request;
+	pca->gpio.free = pca9685_pwm_gpio_free;
+	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
+	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
+	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
+	pca->gpio.get = pca9685_pwm_gpio_get;
+	pca->gpio.set = pca9685_pwm_gpio_set;
+	pca->gpio.base = -1;
+	pca->gpio.ngpio = PCA9685_MAXCHAN;
+	pca->gpio.can_sleep = true;
+
+	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
+}
+#else
+static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
+				       struct pwm_device *pwm)
+{
+	return false;
+}
+
+static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
+{
+	return 0;
+}
+#endif
+
 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			      int duty_ns, int period_ns)
 {
@@ -117,16 +267,6 @@ static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			udelay(500);
 
 			pca->period_ns = period_ns;
-
-			/*
-			 * If the duty cycle did not change, restart PWM with
-			 * the same duty cycle to period ratio and return.
-			 */
-			if (duty_ns == pca->duty_ns) {
-				regmap_update_bits(pca->regmap, PCA9685_MODE1,
-						   MODE1_RESTART, 0x1);
-				return 0;
-			}
 		} else {
 			dev_err(chip->dev,
 				"prescaler not set: period out of bounds!\n");
@@ -264,6 +404,9 @@ static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct pca9685 *pca = to_pca(chip);
 
+	if (pca9685_pwm_is_gpio(pca, pwm))
+		return -EBUSY;
+
 	if (pca->active_cnt++ == 0)
 		return regmap_update_bits(pca->regmap, PCA9685_MODE1,
 					  MODE1_SLEEP, 0x0);
@@ -343,9 +486,16 @@ static int pca9685_pwm_probe(struct i2c_client *client,
 
 	pca->chip.dev = &client->dev;
 	pca->chip.base = -1;
-	pca->chip.can_sleep = true;
 
-	return pwmchip_add(&pca->chip);
+	ret = pwmchip_add(&pca->chip);
+	if (ret < 0)
+		return ret;
+
+	ret = pca9685_pwm_gpio_probe(pca);
+	if (ret < 0)
+		pwmchip_remove(&pca->chip);
+
+	return ret;
 }
 
 static int pca9685_pwm_remove(struct i2c_client *client)
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index 58b709f29130..4143a46684d2 100644
--- a/drivers/pwm/pwm-pxa.c
+++ b/drivers/pwm/pwm-pxa.c
@@ -118,7 +118,7 @@ static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	clk_disable_unprepare(pc->clk);
 }
 
-static struct pwm_ops pxa_pwm_ops = {
+static const struct pwm_ops pxa_pwm_ops = {
 	.config = pxa_pwm_config,
 	.enable = pxa_pwm_enable,
 	.disable = pxa_pwm_disable,
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index dd82dc840af9..2b7c31c9d1ab 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -635,7 +635,6 @@ skip_cpt:
 	pc->chip.ops = &sti_pwm_ops;
 	pc->chip.base = -1;
 	pc->chip.npwm = pc->cdata->pwm_num_devs;
-	pc->chip.can_sleep = true;
 
 	ret = pwmchip_add(&pc->chip);
 	if (ret < 0) {
diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index b0803f6c64d9..1284ffa05921 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -340,7 +340,6 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
 	pwm->chip.npwm = pwm->data->npwm;
-	pwm->chip.can_sleep = true;
 	pwm->chip.of_xlate = of_pwm_xlate_with_flags;
 	pwm->chip.of_pwm_n_cells = 3;
 
diff --git a/drivers/pwm/pwm-twl-led.c b/drivers/pwm/pwm-twl-led.c
index b964470025c5..21eff991d0e3 100644
--- a/drivers/pwm/pwm-twl-led.c
+++ b/drivers/pwm/pwm-twl-led.c
@@ -303,7 +303,6 @@ static int twl_pwmled_probe(struct platform_device *pdev)
 
 	twl->chip.dev = &pdev->dev;
 	twl->chip.base = -1;
-	twl->chip.can_sleep = true;
 
 	mutex_init(&twl->mutex);
 
diff --git a/drivers/pwm/pwm-twl.c b/drivers/pwm/pwm-twl.c
index 7a993b056638..9de617b76680 100644
--- a/drivers/pwm/pwm-twl.c
+++ b/drivers/pwm/pwm-twl.c
@@ -323,7 +323,6 @@ static int twl_pwm_probe(struct platform_device *pdev)
 	twl->chip.dev = &pdev->dev;
 	twl->chip.base = -1;
 	twl->chip.npwm = 2;
-	twl->chip.can_sleep = true;
 
 	mutex_init(&twl->mutex);
 
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
index cdb58fd4619d..8141a4984126 100644
--- a/drivers/pwm/pwm-vt8500.c
+++ b/drivers/pwm/pwm-vt8500.c
@@ -184,7 +184,7 @@ static int vt8500_pwm_set_polarity(struct pwm_chip *chip,
 	return 0;
 }
 
-static struct pwm_ops vt8500_pwm_ops = {
+static const struct pwm_ops vt8500_pwm_ops = {
 	.enable = vt8500_pwm_enable,
 	.disable = vt8500_pwm_disable,
 	.config = vt8500_pwm_config,
diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
index c4bf3298ba07..f0404bc37123 100644
--- a/drivers/staging/greybus/pwm.c
+++ b/drivers/staging/greybus/pwm.c
@@ -284,7 +284,6 @@ static int gb_pwm_probe(struct gbphy_device *gbphy_dev,
 	pwm->ops = &gb_pwm_ops;
 	pwm->base = -1;			/* Allocate base dynamically */
 	pwm->npwm = pwmc->pwm_max + 1;
-	pwm->can_sleep = true;		/* FIXME */
 
 	ret = pwmchip_add(pwm);
 	if (ret) {