pwm: Add Freescale FTM PWM driver support

The FTM PWM device can be found on Vybrid VF610 Tower and
Layerscape LS-1 SoCs.
Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Alison Wang <b18965@freescale.com>
Signed-off-by: Jingchang Lu <b35083@freescale.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/Kconfig

@@ -80,6 +80,16 @@ config PWM_EP93XX
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-ep93xx.
 
+config PWM_FSL_FTM
+	tristate "Freescale FlexTimer Module (FTM) PWM support"
+	depends on OF
+	help
+	  Generic FTM PWM framework driver for Freescale VF610 and
+	  Layerscape LS-1 SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-fsl-ftm.
+
 config PWM_IMX
 	tristate "i.MX PWM support"
 	depends on ARCH_MXC

drivers/pwm/Makefile

@@ -5,6 +5,7 @@ obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
 obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
+obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
 obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
 obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o
 obj-$(CONFIG_PWM_LP3943)	+= pwm-lp3943.o

drivers/pwm/pwm-fsl-ftm.c

+/*
+ *  Freescale FlexTimer Module (FTM) PWM Driver
+ *
+ *  Copyright 2012-2013 Freescale Semiconductor, Inc.
+ *
+ * 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, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define FTM_SC		0x00
+#define FTM_SC_CLK_MASK	0x3
+#define FTM_SC_CLK_SHIFT	3
+#define FTM_SC_CLK(c)	(((c) + 1) << FTM_SC_CLK_SHIFT)
+#define FTM_SC_PS_MASK	0x7
+#define FTM_SC_PS_SHIFT	0
+
+#define FTM_CNT		0x04
+#define FTM_MOD		0x08
+
+#define FTM_CSC_BASE	0x0C
+#define FTM_CSC_MSB	BIT(5)
+#define FTM_CSC_MSA	BIT(4)
+#define FTM_CSC_ELSB	BIT(3)
+#define FTM_CSC_ELSA	BIT(2)
+#define FTM_CSC(_channel)	(FTM_CSC_BASE + ((_channel) * 8))
+
+#define FTM_CV_BASE	0x10
+#define FTM_CV(_channel)	(FTM_CV_BASE + ((_channel) * 8))
+
+#define FTM_CNTIN	0x4C
+#define FTM_STATUS	0x50
+
+#define FTM_MODE	0x54
+#define FTM_MODE_FTMEN	BIT(0)
+#define FTM_MODE_INIT	BIT(2)
+#define FTM_MODE_PWMSYNC	BIT(3)
+
+#define FTM_SYNC	0x58
+#define FTM_OUTINIT	0x5C
+#define FTM_OUTMASK	0x60
+#define FTM_COMBINE	0x64
+#define FTM_DEADTIME	0x68
+#define FTM_EXTTRIG	0x6C
+#define FTM_POL		0x70
+#define FTM_FMS		0x74
+#define FTM_FILTER	0x78
+#define FTM_FLTCTRL	0x7C
+#define FTM_QDCTRL	0x80
+#define FTM_CONF	0x84
+#define FTM_FLTPOL	0x88
+#define FTM_SYNCONF	0x8C
+#define FTM_INVCTRL	0x90
+#define FTM_SWOCTRL	0x94
+#define FTM_PWMLOAD	0x98
+
+enum fsl_pwm_clk {
+	FSL_PWM_CLK_SYS,
+	FSL_PWM_CLK_FIX,
+	FSL_PWM_CLK_EXT,
+	FSL_PWM_CLK_CNTEN,
+	FSL_PWM_CLK_MAX
+};
+
+struct fsl_pwm_chip {
+	struct pwm_chip chip;
+
+	struct mutex lock;
+
+	unsigned int use_count;
+	unsigned int cnt_select;
+	unsigned int clk_ps;
+
+	void __iomem *base;
+
+	int period_ns;
+
+	struct clk *clk[FSL_PWM_CLK_MAX];
+};
+
+static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct fsl_pwm_chip, chip);
+}
+
+static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+
+	return clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
+}
+
+static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+
+	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
+}
+
+static int fsl_pwm_calculate_default_ps(struct fsl_pwm_chip *fpc,
+					enum fsl_pwm_clk index)
+{
+	unsigned long sys_rate, cnt_rate;
+	unsigned long long ratio;
+
+	sys_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_SYS]);
+	if (!sys_rate)
+		return -EINVAL;
+
+	cnt_rate = clk_get_rate(fpc->clk[fpc->cnt_select]);
+	if (!cnt_rate)
+		return -EINVAL;
+
+	switch (index) {
+	case FSL_PWM_CLK_SYS:
+		fpc->clk_ps = 1;
+		break;
+	case FSL_PWM_CLK_FIX:
+		ratio = 2 * cnt_rate - 1;
+		do_div(ratio, sys_rate);
+		fpc->clk_ps = ratio;
+		break;
+	case FSL_PWM_CLK_EXT:
+		ratio = 4 * cnt_rate - 1;
+		do_div(ratio, sys_rate);
+		fpc->clk_ps = ratio;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static unsigned long fsl_pwm_calculate_cycles(struct fsl_pwm_chip *fpc,
+					      unsigned long period_ns)
+{
+	unsigned long long c, c0;
+
+	c = clk_get_rate(fpc->clk[fpc->cnt_select]);
+	c = c * period_ns;
+	do_div(c, 1000000000UL);
+
+	do {
+		c0 = c;
+		do_div(c0, (1 << fpc->clk_ps));
+		if (c0 <= 0xFFFF)
+			return (unsigned long)c0;
+	} while (++fpc->clk_ps < 8);
+
+	return 0;
+}
+
+static unsigned long fsl_pwm_calculate_period_cycles(struct fsl_pwm_chip *fpc,
+						     unsigned long period_ns,
+						     enum fsl_pwm_clk index)
+{
+	int ret;
+
+	ret = fsl_pwm_calculate_default_ps(fpc, index);
+	if (ret) {
+		dev_err(fpc->chip.dev,
+			"failed to calculate default prescaler: %d\n",
+			ret);
+		return 0;
+	}
+
+	return fsl_pwm_calculate_cycles(fpc, period_ns);
+}
+
+static unsigned long fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
+					      unsigned long period_ns)
+{
+	enum fsl_pwm_clk m0, m1;
+	unsigned long fix_rate, ext_rate, cycles;
+
+	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns,
+			FSL_PWM_CLK_SYS);
+	if (cycles) {
+		fpc->cnt_select = FSL_PWM_CLK_SYS;
+		return cycles;
+	}
+
+	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
+	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
+
+	if (fix_rate > ext_rate) {
+		m0 = FSL_PWM_CLK_FIX;
+		m1 = FSL_PWM_CLK_EXT;
+	} else {
+		m0 = FSL_PWM_CLK_EXT;
+		m1 = FSL_PWM_CLK_FIX;
+	}
+
+	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, m0);
+	if (cycles) {
+		fpc->cnt_select = m0;
+		return cycles;
+	}
+
+	fpc->cnt_select = m1;
+
+	return fsl_pwm_calculate_period_cycles(fpc, period_ns, m1);
+}
+
+static unsigned long fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
+					    unsigned long period_ns,
+					    unsigned long duty_ns)
+{
+	unsigned long long val, duty;
+
+	val = readl(fpc->base + FTM_MOD);
+	duty = duty_ns * (val + 1);
+	do_div(duty, period_ns);
+
+	return (unsigned long)duty;
+}
+
+static int fsl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			  int duty_ns, int period_ns)
+{
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+	u32 val, period, duty;
+
+	mutex_lock(&fpc->lock);
+
+	/*
+	 * The Freescale FTM controller supports only a single period for
+	 * all PWM channels, therefore incompatible changes need to be
+	 * refused.
+	 */
+	if (fpc->period_ns && fpc->period_ns != period_ns) {
+		dev_err(fpc->chip.dev,
+			"conflicting period requested for PWM %u\n",
+			pwm->hwpwm);
+		mutex_unlock(&fpc->lock);
+		return -EBUSY;
+	}
+
+	if (!fpc->period_ns && duty_ns) {
+		period = fsl_pwm_calculate_period(fpc, period_ns);
+		if (!period) {
+			dev_err(fpc->chip.dev, "failed to calculate period\n");
+			mutex_unlock(&fpc->lock);
+			return -EINVAL;
+		}
+
+		val = readl(fpc->base + FTM_SC);
+		val &= ~(FTM_SC_PS_MASK << FTM_SC_PS_SHIFT);
+		val |= fpc->clk_ps;
+		writel(val, fpc->base + FTM_SC);
+		writel(period - 1, fpc->base + FTM_MOD);
+
+		fpc->period_ns = period_ns;
+	}
+
+	mutex_unlock(&fpc->lock);
+
+	duty = fsl_pwm_calculate_duty(fpc, period_ns, duty_ns);
+
+	writel(FTM_CSC_MSB | FTM_CSC_ELSB, fpc->base + FTM_CSC(pwm->hwpwm));
+	writel(duty, fpc->base + FTM_CV(pwm->hwpwm));
+
+	return 0;
+}
+
+static int fsl_pwm_set_polarity(struct pwm_chip *chip,
+				struct pwm_device *pwm,
+				enum pwm_polarity polarity)
+{
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+	u32 val;
+
+	val = readl(fpc->base + FTM_POL);
+
+	if (polarity == PWM_POLARITY_INVERSED)
+		val |= BIT(pwm->hwpwm);
+	else
+		val &= ~BIT(pwm->hwpwm);
+
+	writel(val, fpc->base + FTM_POL);
+
+	return 0;
+}
+
+static int fsl_counter_clock_enable(struct fsl_pwm_chip *fpc)
+{
+	u32 val;
+	int ret;
+
+	if (fpc->use_count != 0)
+		return 0;
+
+	/* select counter clock source */
+	val = readl(fpc->base + FTM_SC);
+	val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT);
+	val |= FTM_SC_CLK(fpc->cnt_select);
+	writel(val, fpc->base + FTM_SC);
+
+	ret = clk_prepare_enable(fpc->clk[fpc->cnt_select]);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
+	if (ret) {
+		clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
+		return ret;
+	}
+
+	fpc->use_count++;
+
+	return 0;
+}
+
+static int fsl_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+	u32 val;
+	int ret;
+
+	mutex_lock(&fpc->lock);
+	val = readl(fpc->base + FTM_OUTMASK);
+	val &= ~BIT(pwm->hwpwm);
+	writel(val, fpc->base + FTM_OUTMASK);
+
+	ret = fsl_counter_clock_enable(fpc);
+	mutex_unlock(&fpc->lock);
+
+	return ret;
+}
+
+static void fsl_counter_clock_disable(struct fsl_pwm_chip *fpc)
+{
+	u32 val;
+
+	/*
+	 * already disabled, do nothing
+	 */
+	if (fpc->use_count == 0)
+		return;
+
+	/* there are still users, so can't disable yet */
+	if (--fpc->use_count > 0)
+		return;
+
+	/* no users left, disable PWM counter clock */
+	val = readl(fpc->base + FTM_SC);
+	val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT);
+	writel(val, fpc->base + FTM_SC);
+
+	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
+	clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
+}
+
+static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
+	u32 val;
+
+	mutex_lock(&fpc->lock);
+	val = readl(fpc->base + FTM_OUTMASK);
+	val |= BIT(pwm->hwpwm);
+	writel(val, fpc->base + FTM_OUTMASK);
+
+	fsl_counter_clock_disable(fpc);
+
+	val = readl(fpc->base + FTM_OUTMASK);
+
+	if ((val & 0xFF) == 0xFF)
+		fpc->period_ns = 0;
+
+	mutex_unlock(&fpc->lock);
+}
+
+static const struct pwm_ops fsl_pwm_ops = {
+	.request = fsl_pwm_request,
+	.free = fsl_pwm_free,
+	.config = fsl_pwm_config,
+	.set_polarity = fsl_pwm_set_polarity,
+	.enable = fsl_pwm_enable,
+	.disable = fsl_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
+{
+	int ret;
+
+	ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
+	if (ret)
+		return ret;
+
+	writel(0x00, fpc->base + FTM_CNTIN);
+	writel(0x00, fpc->base + FTM_OUTINIT);
+	writel(0xFF, fpc->base + FTM_OUTMASK);
+
+	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
+
+	return 0;
+}
+
+static int fsl_pwm_probe(struct platform_device *pdev)
+{
+	struct fsl_pwm_chip *fpc;
+	struct resource *res;
+	int ret;
+
+	fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL);
+	if (!fpc)
+		return -ENOMEM;
+
+	mutex_init(&fpc->lock);
+
+	fpc->chip.dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	fpc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(fpc->base))
+		return PTR_ERR(fpc->base);
+
+	fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
+	if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
+		dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
+		return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
+	}
+
+	fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
+	if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
+		return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);
+
+	fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
+	if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
+		return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);
+
+	fpc->clk[FSL_PWM_CLK_CNTEN] =
+				devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
+	if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
+		return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);
+
+	fpc->chip.ops = &fsl_pwm_ops;
+	fpc->chip.of_xlate = of_pwm_xlate_with_flags;
+	fpc->chip.of_pwm_n_cells = 3;
+	fpc->chip.base = -1;
+	fpc->chip.npwm = 8;
+
+	ret = pwmchip_add(&fpc->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, fpc);
+
+	return fsl_pwm_init(fpc);
+}
+
+static int fsl_pwm_remove(struct platform_device *pdev)
+{
+	struct fsl_pwm_chip *fpc = platform_get_drvdata(pdev);
+
+	return pwmchip_remove(&fpc->chip);
+}
+
+static const struct of_device_id fsl_pwm_dt_ids[] = {
+	{ .compatible = "fsl,vf610-ftm-pwm", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);
+
+static struct platform_driver fsl_pwm_driver = {
+	.driver = {
+		.name = "fsl-ftm-pwm",
+		.of_match_table = fsl_pwm_dt_ids,
+	},
+	.probe = fsl_pwm_probe,
+	.remove = fsl_pwm_remove,
+};
+module_platform_driver(fsl_pwm_driver);
+
+MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
+MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
+MODULE_ALIAS("platform:fsl-ftm-pwm");
+MODULE_LICENSE("GPL");