1 files changed, 531 insertions, 236 deletions

diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
index a0ece50d70bb..951b38ff5f8e 100644
--- a/drivers/pwm/pwm-samsung.c
+++ b/drivers/pwm/pwm-samsung.c
@@ -1,353 +1,648 @@
-/* drivers/pwm/pwm-samsung.c
- *
+// SPDX-License-Identifier: GPL-2.0-only
+/*
  * Copyright (c) 2007 Ben Dooks
  * Copyright (c) 2008 Simtec Electronics
- *	Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
- *
- * S3C series PWM device core
+ *     Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
+ * Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
+ * Copyright (c) 2017 Samsung Electronics Co., Ltd.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License.
-*/
-
-#define pr_fmt(fmt) "pwm-samsung: " fmt
+ * PWM driver for Samsung SoCs
+ */
 
+#include <linux/bitops.h>
+#include <linux/clk.h>
 #include <linux/export.h>
-#include <linux/kernel.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
 #include <linux/err.h>
-#include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
 #include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/time.h>
 
-#include <mach/map.h>
+/* For struct samsung_timer_variant and samsung_pwm_lock. */
+#include <clocksource/samsung_pwm.h>
 
-#include <plat/regs-timer.h>
+#define REG_TCFG0			0x00
+#define REG_TCFG1			0x04
+#define REG_TCON			0x08
 
-struct s3c_chip {
-	struct platform_device	*pdev;
+#define REG_TCNTB(chan)			(0x0c + ((chan) * 0xc))
+#define REG_TCMPB(chan)			(0x10 + ((chan) * 0xc))
 
-	struct clk		*clk_div;
-	struct clk		*clk;
-	const char		*label;
+#define TCFG0_PRESCALER_MASK		0xff
+#define TCFG0_PRESCALER1_SHIFT		8
 
-	unsigned int		 period_ns;
-	unsigned int		 duty_ns;
+#define TCFG1_MUX_MASK			0xf
+#define TCFG1_SHIFT(chan)		(4 * (chan))
 
-	unsigned char		 tcon_base;
-	unsigned char		 pwm_id;
-	struct pwm_chip		 chip;
+/*
+ * Each channel occupies 4 bits in TCON register, but there is a gap of 4
+ * bits (one channel) after channel 0, so channels have different numbering
+ * when accessing TCON register. See to_tcon_channel() function.
+ *
+ * In addition, the location of autoreload bit for channel 4 (TCON channel 5)
+ * in its set of bits is 2 as opposed to 3 for other channels.
+ */
+#define TCON_START(chan)		BIT(4 * (chan) + 0)
+#define TCON_MANUALUPDATE(chan)		BIT(4 * (chan) + 1)
+#define TCON_INVERT(chan)		BIT(4 * (chan) + 2)
+#define _TCON_AUTORELOAD(chan)		BIT(4 * (chan) + 3)
+#define _TCON_AUTORELOAD4(chan)		BIT(4 * (chan) + 2)
+#define TCON_AUTORELOAD(chan)		\
+	((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))
+
+/**
+ * struct samsung_pwm_channel - private data of PWM channel
+ * @period_ns:	current period in nanoseconds programmed to the hardware
+ * @duty_ns:	current duty time in nanoseconds programmed to the hardware
+ * @tin_ns:	time of one timer tick in nanoseconds with current timer rate
+ */
+struct samsung_pwm_channel {
+	u32 period_ns;
+	u32 duty_ns;
+	u32 tin_ns;
 };
 
-#define to_s3c_chip(chip)	container_of(chip, struct s3c_chip, chip)
+/**
+ * struct samsung_pwm_chip - private data of PWM chip
+ * @variant:		local copy of hardware variant data
+ * @inverter_mask:	inverter status for all channels - one bit per channel
+ * @disabled_mask:	disabled status for all channels - one bit per channel
+ * @base:		base address of mapped PWM registers
+ * @base_clk:		base clock used to drive the timers
+ * @tclk0:		external clock 0 (can be ERR_PTR if not present)
+ * @tclk1:		external clock 1 (can be ERR_PTR if not present)
+ * @channel:		per channel driver data
+ */
+struct samsung_pwm_chip {
+	struct samsung_pwm_variant variant;
+	u8 inverter_mask;
+	u8 disabled_mask;
+
+	void __iomem *base;
+	struct clk *base_clk;
+	struct clk *tclk0;
+	struct clk *tclk1;
+	struct samsung_pwm_channel channel[SAMSUNG_PWM_NUM];
+};
 
-#define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg)
+#ifndef CONFIG_CLKSRC_SAMSUNG_PWM
+/*
+ * PWM block is shared between pwm-samsung and samsung_pwm_timer drivers
+ * and some registers need access synchronization. If both drivers are
+ * compiled in, the spinlock is defined in the clocksource driver,
+ * otherwise following definition is used.
+ *
+ * Currently we do not need any more complex synchronization method
+ * because all the supported SoCs contain only one instance of the PWM
+ * IP. Should this change, both drivers will need to be modified to
+ * properly synchronize accesses to particular instances.
+ */
+static DEFINE_SPINLOCK(samsung_pwm_lock);
+#endif
 
-static struct clk *clk_scaler[2];
+static inline
+struct samsung_pwm_chip *to_samsung_pwm_chip(struct pwm_chip *chip)
+{
+	return pwmchip_get_drvdata(chip);
+}
 
-static inline int pwm_is_tdiv(struct s3c_chip *chip)
+static inline unsigned int to_tcon_channel(unsigned int channel)
 {
-	return clk_get_parent(chip->clk) == chip->clk_div;
+	/* TCON register has a gap of 4 bits (1 channel) after channel 0 */
+	return (channel == 0) ? 0 : (channel + 1);
 }
 
-#define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0))
-#define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2))
-#define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3))
-#define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1))
+static void __pwm_samsung_manual_update(struct samsung_pwm_chip *our_chip,
+				      struct pwm_device *pwm)
+{
+	unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
+	u32 tcon;
+
+	tcon = readl(our_chip->base + REG_TCON);
+	tcon |= TCON_MANUALUPDATE(tcon_chan);
+	writel(tcon, our_chip->base + REG_TCON);
 
-static int s3c_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+	tcon &= ~TCON_MANUALUPDATE(tcon_chan);
+	writel(tcon, our_chip->base + REG_TCON);
+}
+
+static void pwm_samsung_set_divisor(struct samsung_pwm_chip *our_chip,
+				    unsigned int channel, u8 divisor)
 {
-	struct s3c_chip *s3c = to_s3c_chip(chip);
+	u8 shift = TCFG1_SHIFT(channel);
 	unsigned long flags;
-	unsigned long tcon;
+	u32 reg;
+	u8 bits;
 
-	local_irq_save(flags);
+	bits = (fls(divisor) - 1) - our_chip->variant.div_base;
 
-	tcon = __raw_readl(S3C2410_TCON);
-	tcon |= pwm_tcon_start(s3c);
-	__raw_writel(tcon, S3C2410_TCON);
+	spin_lock_irqsave(&samsung_pwm_lock, flags);
 
-	local_irq_restore(flags);
+	reg = readl(our_chip->base + REG_TCFG1);
+	reg &= ~(TCFG1_MUX_MASK << shift);
+	reg |= bits << shift;
+	writel(reg, our_chip->base + REG_TCFG1);
 
-	return 0;
+	spin_unlock_irqrestore(&samsung_pwm_lock, flags);
 }
 
-static void s3c_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *our_chip, unsigned int chan)
 {
-	struct s3c_chip *s3c = to_s3c_chip(chip);
-	unsigned long flags;
-	unsigned long tcon;
+	struct samsung_pwm_variant *variant = &our_chip->variant;
+	u32 reg;
+
+	reg = readl(our_chip->base + REG_TCFG1);
+	reg >>= TCFG1_SHIFT(chan);
+	reg &= TCFG1_MUX_MASK;
 
-	local_irq_save(flags);
+	return (BIT(reg) & variant->tclk_mask) == 0;
+}
 
-	tcon = __raw_readl(S3C2410_TCON);
-	tcon &= ~pwm_tcon_start(s3c);
-	__raw_writel(tcon, S3C2410_TCON);
+static unsigned long pwm_samsung_get_tin_rate(struct samsung_pwm_chip *our_chip,
+					      unsigned int chan)
+{
+	unsigned long rate;
+	u32 reg;
 
-	local_irq_restore(flags);
+	rate = clk_get_rate(our_chip->base_clk);
+
+	reg = readl(our_chip->base + REG_TCFG0);
+	if (chan >= 2)
+		reg >>= TCFG0_PRESCALER1_SHIFT;
+	reg &= TCFG0_PRESCALER_MASK;
+
+	return rate / (reg + 1);
 }
 
-static unsigned long pwm_calc_tin(struct s3c_chip *s3c, unsigned long freq)
+static unsigned long pwm_samsung_calc_tin(struct pwm_chip *chip,
+					  unsigned int chan, unsigned long freq)
 {
-	unsigned long tin_parent_rate;
-	unsigned int div;
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	struct samsung_pwm_variant *variant = &our_chip->variant;
+	unsigned long rate;
+	struct clk *clk;
+	u8 div;
+
+	if (!pwm_samsung_is_tdiv(our_chip, chan)) {
+		clk = (chan < 2) ? our_chip->tclk0 : our_chip->tclk1;
+		if (!IS_ERR(clk)) {
+			rate = clk_get_rate(clk);
+			if (rate)
+				return rate;
+		}
+
+		dev_warn(pwmchip_parent(chip),
+			"tclk of PWM %d is inoperational, using tdiv\n", chan);
+	}
 
-	tin_parent_rate = clk_get_rate(clk_get_parent(s3c->clk_div));
-	pwm_dbg(s3c, "tin parent at %lu\n", tin_parent_rate);
+	rate = pwm_samsung_get_tin_rate(our_chip, chan);
+	dev_dbg(pwmchip_parent(chip), "tin parent at %lu\n", rate);
 
-	for (div = 2; div <= 16; div *= 2) {
-		if ((tin_parent_rate / (div << 16)) < freq)
-			return tin_parent_rate / div;
+	/*
+	 * Compare minimum PWM frequency that can be achieved with possible
+	 * divider settings and choose the lowest divisor that can generate
+	 * frequencies lower than requested.
+	 */
+	if (variant->bits < 32) {
+		/* Only for s3c24xx */
+		for (div = variant->div_base; div < 4; ++div)
+			if ((rate >> (variant->bits + div)) < freq)
+				break;
+	} else {
+		/*
+		 * Other variants have enough counter bits to generate any
+		 * requested rate, so no need to check higher divisors.
+		 */
+		div = variant->div_base;
 	}
 
-	return tin_parent_rate / 16;
+	pwm_samsung_set_divisor(our_chip, chan, BIT(div));
+
+	return rate >> div;
 }
 
-#define NS_IN_HZ (1000000000UL)
+static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+
+	if (!(our_chip->variant.output_mask & BIT(pwm->hwpwm))) {
+		dev_warn(pwmchip_parent(chip),
+			"tried to request PWM channel %d without output\n",
+			pwm->hwpwm);
+		return -EINVAL;
+	}
+
+	memset(&our_chip->channel[pwm->hwpwm], 0, sizeof(our_chip->channel[pwm->hwpwm]));
+
+	return 0;
+}
 
-static int s3c_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-		int duty_ns, int period_ns)
+static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
-	struct s3c_chip *s3c = to_s3c_chip(chip);
-	unsigned long tin_rate;
-	unsigned long tin_ns;
-	unsigned long period;
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
 	unsigned long flags;
-	unsigned long tcon;
-	unsigned long tcnt;
-	long tcmp;
+	u32 tcon;
 
-	/* We currently avoid using 64bit arithmetic by using the
-	 * fact that anything faster than 1Hz is easily representable
-	 * by 32bits. */
+	spin_lock_irqsave(&samsung_pwm_lock, flags);
 
-	if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
-		return -ERANGE;
+	tcon = readl(our_chip->base + REG_TCON);
 
-	if (period_ns == s3c->period_ns &&
-	    duty_ns == s3c->duty_ns)
-		return 0;
+	tcon &= ~TCON_START(tcon_chan);
+	tcon |= TCON_MANUALUPDATE(tcon_chan);
+	writel(tcon, our_chip->base + REG_TCON);
 
-	/* The TCMP and TCNT can be read without a lock, they're not
-	 * shared between the timers. */
+	tcon &= ~TCON_MANUALUPDATE(tcon_chan);
+	tcon |= TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan);
+	writel(tcon, our_chip->base + REG_TCON);
 
-	tcmp = __raw_readl(S3C2410_TCMPB(s3c->pwm_id));
-	tcnt = __raw_readl(S3C2410_TCNTB(s3c->pwm_id));
+	our_chip->disabled_mask &= ~BIT(pwm->hwpwm);
 
-	period = NS_IN_HZ / period_ns;
+	spin_unlock_irqrestore(&samsung_pwm_lock, flags);
 
-	pwm_dbg(s3c, "duty_ns=%d, period_ns=%d (%lu)\n",
-		duty_ns, period_ns, period);
+	return 0;
+}
 
-	/* Check to see if we are changing the clock rate of the PWM */
+static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
+	unsigned long flags;
+	u32 tcon;
 
-	if (s3c->period_ns != period_ns) {
-		if (pwm_is_tdiv(s3c)) {
-			tin_rate = pwm_calc_tin(s3c, period);
-			clk_set_rate(s3c->clk_div, tin_rate);
-		} else
-			tin_rate = clk_get_rate(s3c->clk);
+	spin_lock_irqsave(&samsung_pwm_lock, flags);
 
-		s3c->period_ns = period_ns;
+	tcon = readl(our_chip->base + REG_TCON);
+	tcon &= ~TCON_AUTORELOAD(tcon_chan);
+	writel(tcon, our_chip->base + REG_TCON);
 
-		pwm_dbg(s3c, "tin_rate=%lu\n", tin_rate);
+	/*
+	 * In case the PWM is at 100% duty cycle, force a manual
+	 * update to prevent the signal from staying high.
+	 */
+	if (readl(our_chip->base + REG_TCMPB(pwm->hwpwm)) == (u32)-1U)
+		__pwm_samsung_manual_update(our_chip, pwm);
 
-		tin_ns = NS_IN_HZ / tin_rate;
-		tcnt = period_ns / tin_ns;
-	} else
-		tin_ns = NS_IN_HZ / clk_get_rate(s3c->clk);
+	our_chip->disabled_mask |= BIT(pwm->hwpwm);
 
-	/* Note, counters count down */
+	spin_unlock_irqrestore(&samsung_pwm_lock, flags);
+}
 
-	tcmp = duty_ns / tin_ns;
-	tcmp = tcnt - tcmp;
-	/* the pwm hw only checks the compare register after a decrement,
-	   so the pin never toggles if tcmp = tcnt */
-	if (tcmp == tcnt)
-		tcmp--;
+static void pwm_samsung_manual_update(struct samsung_pwm_chip *our_chip,
+				      struct pwm_device *pwm)
+{
+	unsigned long flags;
 
-	pwm_dbg(s3c, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt);
+	spin_lock_irqsave(&samsung_pwm_lock, flags);
 
-	if (tcmp < 0)
-		tcmp = 0;
+	__pwm_samsung_manual_update(our_chip, pwm);
 
-	/* Update the PWM register block. */
+	spin_unlock_irqrestore(&samsung_pwm_lock, flags);
+}
 
-	local_irq_save(flags);
+static int __pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
+				int duty_ns, int period_ns, bool force_period)
+{
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	struct samsung_pwm_channel *chan = &our_chip->channel[pwm->hwpwm];
+	u32 tin_ns = chan->tin_ns, tcnt, tcmp, oldtcmp;
 
-	__raw_writel(tcmp, S3C2410_TCMPB(s3c->pwm_id));
-	__raw_writel(tcnt, S3C2410_TCNTB(s3c->pwm_id));
+	tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
+	oldtcmp = readl(our_chip->base + REG_TCMPB(pwm->hwpwm));
 
-	tcon = __raw_readl(S3C2410_TCON);
-	tcon |= pwm_tcon_manulupdate(s3c);
-	tcon |= pwm_tcon_autoreload(s3c);
-	__raw_writel(tcon, S3C2410_TCON);
+	/* We need tick count for calculation, not last tick. */
+	++tcnt;
 
-	tcon &= ~pwm_tcon_manulupdate(s3c);
-	__raw_writel(tcon, S3C2410_TCON);
+	/* Check to see if we are changing the clock rate of the PWM. */
+	if (chan->period_ns != period_ns || force_period) {
+		unsigned long tin_rate;
+		u32 period;
 
-	local_irq_restore(flags);
+		period = NSEC_PER_SEC / period_ns;
 
-	return 0;
-}
+		dev_dbg(pwmchip_parent(chip), "duty_ns=%d, period_ns=%d (%u)\n",
+						duty_ns, period_ns, period);
 
-static struct pwm_ops s3c_pwm_ops = {
-	.enable = s3c_pwm_enable,
-	.disable = s3c_pwm_disable,
-	.config = s3c_pwm_config,
-	.owner = THIS_MODULE,
-};
+		tin_rate = pwm_samsung_calc_tin(chip, pwm->hwpwm, period);
 
-static int s3c_pwm_probe(struct platform_device *pdev)
-{
-	struct device *dev = &pdev->dev;
-	struct s3c_chip *s3c;
-	unsigned long flags;
-	unsigned long tcon;
-	unsigned int id = pdev->id;
-	int ret;
+		dev_dbg(pwmchip_parent(chip), "tin_rate=%lu\n", tin_rate);
 
-	if (id == 4) {
-		dev_err(dev, "TIMER4 is currently not supported\n");
-		return -ENXIO;
+		tin_ns = NSEC_PER_SEC / tin_rate;
+		tcnt = period_ns / tin_ns;
 	}
 
-	s3c = devm_kzalloc(&pdev->dev, sizeof(*s3c), GFP_KERNEL);
-	if (s3c == NULL) {
-		dev_err(dev, "failed to allocate pwm_device\n");
-		return -ENOMEM;
-	}
+	/* Period is too short. */
+	if (tcnt <= 1)
+		return -ERANGE;
 
-	/* calculate base of control bits in TCON */
-	s3c->tcon_base = id == 0 ? 0 : (id * 4) + 4;
-	s3c->pwm_id = id;
-	s3c->chip.dev = &pdev->dev;
-	s3c->chip.ops = &s3c_pwm_ops;
-	s3c->chip.base = -1;
-	s3c->chip.npwm = 1;
-
-	s3c->clk = devm_clk_get(dev, "pwm-tin");
-	if (IS_ERR(s3c->clk)) {
-		dev_err(dev, "failed to get pwm tin clk\n");
-		return PTR_ERR(s3c->clk);
-	}
+	/* Note that counters count down. */
+	tcmp = duty_ns / tin_ns;
 
-	s3c->clk_div = devm_clk_get(dev, "pwm-tdiv");
-	if (IS_ERR(s3c->clk_div)) {
-		dev_err(dev, "failed to get pwm tdiv clk\n");
-		return PTR_ERR(s3c->clk_div);
-	}
+	/* 0% duty is not available */
+	if (!tcmp)
+		++tcmp;
 
-	clk_enable(s3c->clk);
-	clk_enable(s3c->clk_div);
+	tcmp = tcnt - tcmp;
 
-	local_irq_save(flags);
+	/* Decrement to get tick numbers, instead of tick counts. */
+	--tcnt;
+	/* -1UL will give 100% duty. */
+	--tcmp;
 
-	tcon = __raw_readl(S3C2410_TCON);
-	tcon |= pwm_tcon_invert(s3c);
-	__raw_writel(tcon, S3C2410_TCON);
+	dev_dbg(pwmchip_parent(chip), "tin_ns=%u, tcmp=%u/%u\n", tin_ns, tcmp, tcnt);
 
-	local_irq_restore(flags);
+	/* Update PWM registers. */
+	writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
+	writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
 
-	ret = pwmchip_add(&s3c->chip);
-	if (ret < 0) {
-		dev_err(dev, "failed to register pwm\n");
-		goto err_clk_tdiv;
+	/*
+	 * In case the PWM is currently at 100% duty cycle, force a manual
+	 * update to prevent the signal staying high if the PWM is disabled
+	 * shortly afer this update (before it autoreloaded the new values).
+	 */
+	if (oldtcmp == (u32) -1) {
+		dev_dbg(pwmchip_parent(chip), "Forcing manual update");
+		pwm_samsung_manual_update(our_chip, pwm);
 	}
 
-	pwm_dbg(s3c, "config bits %02x\n",
-		(__raw_readl(S3C2410_TCON) >> s3c->tcon_base) & 0x0f);
-
-	dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
-		 clk_get_rate(s3c->clk),
-		 clk_get_rate(s3c->clk_div),
-		 pwm_is_tdiv(s3c) ? "div" : "ext", s3c->tcon_base);
+	chan->period_ns = period_ns;
+	chan->tin_ns = tin_ns;
+	chan->duty_ns = duty_ns;
 
-	platform_set_drvdata(pdev, s3c);
 	return 0;
+}
 
- err_clk_tdiv:
-	clk_disable(s3c->clk_div);
-	clk_disable(s3c->clk);
-	return ret;
+static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			      int duty_ns, int period_ns)
+{
+	return __pwm_samsung_config(chip, pwm, duty_ns, period_ns, false);
 }
 
-static int s3c_pwm_remove(struct platform_device *pdev)
+static void pwm_samsung_set_invert(struct samsung_pwm_chip *our_chip,
+				   unsigned int channel, bool invert)
 {
-	struct s3c_chip *s3c = platform_get_drvdata(pdev);
-	int err;
+	unsigned int tcon_chan = to_tcon_channel(channel);
+	unsigned long flags;
+	u32 tcon;
 
-	err = pwmchip_remove(&s3c->chip);
-	if (err < 0)
-		return err;
+	spin_lock_irqsave(&samsung_pwm_lock, flags);
 
-	clk_disable(s3c->clk_div);
-	clk_disable(s3c->clk);
+	tcon = readl(our_chip->base + REG_TCON);
 
-	return 0;
+	if (invert) {
+		our_chip->inverter_mask |= BIT(channel);
+		tcon |= TCON_INVERT(tcon_chan);
+	} else {
+		our_chip->inverter_mask &= ~BIT(channel);
+		tcon &= ~TCON_INVERT(tcon_chan);
+	}
+
+	writel(tcon, our_chip->base + REG_TCON);
+
+	spin_unlock_irqrestore(&samsung_pwm_lock, flags);
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int s3c_pwm_suspend(struct device *dev)
+static int pwm_samsung_set_polarity(struct pwm_chip *chip,
+				    struct pwm_device *pwm,
+				    enum pwm_polarity polarity)
 {
-	struct s3c_chip *s3c = dev_get_drvdata(dev);
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	bool invert = (polarity == PWM_POLARITY_NORMAL);
 
-	/* No one preserve these values during suspend so reset them
-	 * Otherwise driver leaves PWM unconfigured if same values
-	 * passed to pwm_config
-	 */
-	s3c->period_ns = 0;
-	s3c->duty_ns = 0;
+	/* Inverted means normal in the hardware. */
+	pwm_samsung_set_invert(our_chip, pwm->hwpwm, invert);
 
 	return 0;
 }
 
-static int s3c_pwm_resume(struct device *dev)
+static int pwm_samsung_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			     const struct pwm_state *state)
 {
-	struct s3c_chip *s3c = dev_get_drvdata(dev);
-	unsigned long tcon;
+	int err, enabled = pwm->state.enabled;
 
-	/* Restore invertion */
-	tcon = __raw_readl(S3C2410_TCON);
-	tcon |= pwm_tcon_invert(s3c);
-	__raw_writel(tcon, S3C2410_TCON);
+	if (state->polarity != pwm->state.polarity) {
+		if (enabled) {
+			pwm_samsung_disable(chip, pwm);
+			enabled = false;
+		}
 
-	return 0;
+		err = pwm_samsung_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			pwm_samsung_disable(chip, pwm);
+
+		return 0;
+	}
+
+	/*
+	 * We currently avoid using 64bit arithmetic by using the
+	 * fact that anything faster than 1Hz is easily representable
+	 * by 32bits.
+	 */
+	if (state->period > NSEC_PER_SEC)
+		return -ERANGE;
+
+	err = pwm_samsung_config(chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!pwm->state.enabled)
+		err = pwm_samsung_enable(chip, pwm);
+
+	return err;
 }
-#endif
 
-static SIMPLE_DEV_PM_OPS(s3c_pwm_pm_ops, s3c_pwm_suspend,
-			s3c_pwm_resume);
+static const struct pwm_ops pwm_samsung_ops = {
+	.request	= pwm_samsung_request,
+	.apply		= pwm_samsung_apply,
+};
 
-static struct platform_driver s3c_pwm_driver = {
-	.driver		= {
-		.name	= "s3c24xx-pwm",
-		.owner	= THIS_MODULE,
-		.pm	= &s3c_pwm_pm_ops,
-	},
-	.probe		= s3c_pwm_probe,
-	.remove		= s3c_pwm_remove,
+#ifdef CONFIG_OF
+static const struct samsung_pwm_variant s3c24xx_variant = {
+	.bits		= 16,
+	.div_base	= 1,
+	.has_tint_cstat	= false,
+	.tclk_mask	= BIT(4),
+};
+
+static const struct samsung_pwm_variant s3c64xx_variant = {
+	.bits		= 32,
+	.div_base	= 0,
+	.has_tint_cstat	= true,
+	.tclk_mask	= BIT(7) | BIT(6) | BIT(5),
+};
+
+static const struct samsung_pwm_variant s5p64x0_variant = {
+	.bits		= 32,
+	.div_base	= 0,
+	.has_tint_cstat	= true,
+	.tclk_mask	= 0,
 };
 
-static int __init pwm_init(void)
+static const struct samsung_pwm_variant s5pc100_variant = {
+	.bits		= 32,
+	.div_base	= 0,
+	.has_tint_cstat	= true,
+	.tclk_mask	= BIT(5),
+};
+
+static const struct of_device_id samsung_pwm_matches[] = {
+	{ .compatible = "samsung,s3c2410-pwm", .data = &s3c24xx_variant },
+	{ .compatible = "samsung,s3c6400-pwm", .data = &s3c64xx_variant },
+	{ .compatible = "samsung,s5p6440-pwm", .data = &s5p64x0_variant },
+	{ .compatible = "samsung,s5pc100-pwm", .data = &s5pc100_variant },
+	{ .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant },
+	{},
+};
+MODULE_DEVICE_TABLE(of, samsung_pwm_matches);
+
+static int pwm_samsung_parse_dt(struct pwm_chip *chip)
 {
-	int ret;
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	struct device_node *np = pwmchip_parent(chip)->of_node;
+	const struct of_device_id *match;
+	u32 val;
+
+	match = of_match_node(samsung_pwm_matches, np);
+	if (!match)
+		return -ENODEV;
+
+	memcpy(&our_chip->variant, match->data, sizeof(our_chip->variant));
+
+	of_property_for_each_u32(np, "samsung,pwm-outputs", val) {
+		if (val >= SAMSUNG_PWM_NUM) {
+			dev_err(pwmchip_parent(chip),
+				"%s: invalid channel index in samsung,pwm-outputs property\n",
+								__func__);
+			continue;
+		}
+		our_chip->variant.output_mask |= BIT(val);
+	}
 
-	clk_scaler[0] = clk_get(NULL, "pwm-scaler0");
-	clk_scaler[1] = clk_get(NULL, "pwm-scaler1");
+	return 0;
+}
+#else
+static int pwm_samsung_parse_dt(struct pwm_chip *chip)
+{
+	return -ENODEV;
+}
+#endif
 
-	if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) {
-		pr_err("failed to get scaler clocks\n");
-		return -EINVAL;
+static int pwm_samsung_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct samsung_pwm_chip *our_chip;
+	struct pwm_chip *chip;
+	unsigned int chan;
+	int ret;
+
+	chip = devm_pwmchip_alloc(&pdev->dev, SAMSUNG_PWM_NUM, sizeof(*our_chip));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	our_chip = to_samsung_pwm_chip(chip);
+
+	chip->ops = &pwm_samsung_ops;
+	our_chip->inverter_mask = BIT(SAMSUNG_PWM_NUM) - 1;
+
+	if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
+		ret = pwm_samsung_parse_dt(chip);
+		if (ret)
+			return ret;
+	} else {
+		if (!pdev->dev.platform_data)
+			return dev_err_probe(&pdev->dev, -EINVAL,
+					     "no platform data specified\n");
+
+		memcpy(&our_chip->variant, pdev->dev.platform_data,
+							sizeof(our_chip->variant));
 	}
 
-	ret = platform_driver_register(&s3c_pwm_driver);
-	if (ret)
-		pr_err("failed to add pwm driver\n");
+	our_chip->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(our_chip->base))
+		return PTR_ERR(our_chip->base);
+
+	our_chip->base_clk = devm_clk_get_enabled(&pdev->dev, "timers");
+	if (IS_ERR(our_chip->base_clk))
+		return dev_err_probe(dev, PTR_ERR(our_chip->base_clk),
+				     "failed to get timer base clk\n");
 
-	return ret;
+	for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan)
+		if (our_chip->variant.output_mask & BIT(chan))
+			pwm_samsung_set_invert(our_chip, chan, true);
+
+	/* Following clocks are optional. */
+	our_chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0");
+	our_chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1");
+
+	platform_set_drvdata(pdev, chip);
+
+	ret = devm_pwmchip_add(&pdev->dev, chip);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to register PWM chip\n");
+
+	dev_dbg(dev, "base_clk at %lu, tclk0 at %lu, tclk1 at %lu\n",
+		clk_get_rate(our_chip->base_clk),
+		!IS_ERR(our_chip->tclk0) ? clk_get_rate(our_chip->tclk0) : 0,
+		!IS_ERR(our_chip->tclk1) ? clk_get_rate(our_chip->tclk1) : 0);
+
+	return 0;
 }
 
-arch_initcall(pwm_init);
+static int pwm_samsung_resume(struct device *dev)
+{
+	struct pwm_chip *chip = dev_get_drvdata(dev);
+	struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
+	unsigned int i;
+
+	for (i = 0; i < SAMSUNG_PWM_NUM; i++) {
+		struct pwm_device *pwm = &chip->pwms[i];
+		struct samsung_pwm_channel *chan = &our_chip->channel[i];
+
+		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
+			continue;
+
+		if (our_chip->variant.output_mask & BIT(i))
+			pwm_samsung_set_invert(our_chip, i,
+					our_chip->inverter_mask & BIT(i));
+
+		if (chan->period_ns) {
+			__pwm_samsung_config(chip, pwm, chan->duty_ns,
+					     chan->period_ns, true);
+			/* needed to make PWM disable work on Odroid-XU3 */
+			pwm_samsung_manual_update(our_chip, pwm);
+		}
+
+		if (our_chip->disabled_mask & BIT(i))
+			pwm_samsung_disable(chip, pwm);
+		else
+			pwm_samsung_enable(chip, pwm);
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(pwm_samsung_pm_ops, NULL, pwm_samsung_resume);
+
+static struct platform_driver pwm_samsung_driver = {
+	.driver		= {
+		.name	= "samsung-pwm",
+		.pm	= pm_ptr(&pwm_samsung_pm_ops),
+		.of_match_table = of_match_ptr(samsung_pwm_matches),
+	},
+	.probe		= pwm_samsung_probe,
+};
+module_platform_driver(pwm_samsung_driver);
+
+MODULE_DESCRIPTION("Samsung Pulse Width Modulator driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomasz Figa <tomasz.figa@gmail.com>");
+MODULE_ALIAS("platform:samsung-pwm");