RE: [PATCHv9 1/4] pwm: Add Freescale FTM PWM driver support

[Yao Yuan]

> Subject: [PATCHv9 1/4] 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@xxxxxxxxxxxxx>
> ---

For this patch series,
Reviewed-by: Yuan Yao <yao.yuan@xxxxxxxxxxxxx>


Thanks.


> 
> 
> Hi Thierry,
> 
> For this version I just removed the big-endian mode support, and will add
> it in later separate patches.
> 
> 
> Changes in v9:
> - Remove the big-endian mode support.
> 
> Changes in v7 ~ v8:
> - Mainly about big-endian mode support.
> 
> [snip] v1~v6
> 
> 
> 
>  drivers/pwm/Kconfig       |  10 +
>  drivers/pwm/Makefile      |   1 +
>  drivers/pwm/pwm-fsl-ftm.c | 479
> ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 490 insertions(+)
>  create mode 100644 drivers/pwm/pwm-fsl-ftm.c
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index
> 6a2a1e0a..9a4c641 100644
> --- a/drivers/pwm/Kconfig
> +++ b/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
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index
> 1b99cfb..c22905c 100644
> --- a/drivers/pwm/Makefile
> +++ b/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_LPC32XX)	+= pwm-lpc32xx.o
> diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c new
> file mode 100644 index 0000000..60467b3
> --- /dev/null
> +++ b/drivers/pwm/pwm-fsl-ftm.c
> @@ -0,0 +1,479 @@
> +/*
> + *  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,
> +};
> +
> +struct fsl_pwm_chip {
> +	struct pwm_chip chip;
> +
> +	struct mutex lock;
> +
> +	struct clk *sys_clk;
> +	struct clk *counter_clk;
> +	struct clk *counter_clk_en;
> +	unsigned int counter_clk_select;
> +	unsigned int counter_clk_enable;
> +	unsigned int clk_ps;
> +
> +	void __iomem *base;
> +
> +	int period_ns;
> +};
> +
> +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->sys_clk); }
> +
> +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->sys_clk);
> +}
> +
> +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->sys_clk);
> +	if (!sys_rate)
> +		return -EINVAL;
> +
> +	cnt_rate = clk_get_rate(fpc->counter_clk);
> +	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;
> +	}
> +
> +	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->counter_clk);
> +	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;
> +
> +	fpc->counter_clk_select = FTM_SC_CLK(index);
> +
> +	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)
> +{
> +	struct clk *cnt_clk[3];
> +	enum fsl_pwm_clk m0, m1;
> +	unsigned long fix_rate, ext_rate, cycles;
> +
> +	fpc->counter_clk = fpc->sys_clk;
> +	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns,
> +			FSL_PWM_CLK_SYS);
> +	if (cycles)
> +		return cycles;
> +
> +	cnt_clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
> +	if (IS_ERR(cnt_clk[FSL_PWM_CLK_FIX]))
> +		return PTR_ERR(cnt_clk[FSL_PWM_CLK_FIX]);
> +
> +	cnt_clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
> +	if (IS_ERR(cnt_clk[FSL_PWM_CLK_EXT]))
> +		return PTR_ERR(cnt_clk[FSL_PWM_CLK_EXT]);
> +
> +	fpc->counter_clk_en = devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
> +	if (IS_ERR(fpc->counter_clk_en))
> +		return PTR_ERR(fpc->counter_clk_en);
> +
> +	fix_rate = clk_get_rate(cnt_clk[FSL_PWM_CLK_FIX]);
> +	ext_rate = clk_get_rate(cnt_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;
> +	}
> +
> +	fpc->counter_clk = cnt_clk[m0];
> +	cycles = fsl_pwm_calculate_period_cycles(fpc, period_ns, m0);
> +	if (cycles)
> +		return cycles;
> +
> +	fpc->counter_clk = cnt_clk[m1];
> +
> +	return fsl_pwm_calculate_period_cycles(fpc, period_ns, m0); }
> +
> +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->counter_clk_enable++)
> +		return 0;
> +
> +	ret = clk_prepare_enable(fpc->counter_clk);
> +	if (ret) {
> +		fpc->counter_clk_enable--;
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(fpc->counter_clk_en);
> +	if (ret) {
> +		fpc->counter_clk_enable--;
> +		return ret;
> +	}
> +
> +	/* select counter clock source */
> +	val = readl(fpc->base + FTM_SC);
> +	val &= ~(FTM_SC_CLK_MASK << FTM_SC_CLK_SHIFT);
> +	val |= fpc->counter_clk_select;
> +	writel(val, fpc->base + FTM_SC);
> +
> +	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;
> +
> +	val = readl(fpc->base + FTM_OUTMASK);
> +	val &= ~BIT(pwm->hwpwm);
> +	writel(val, fpc->base + FTM_OUTMASK);
> +
> +	mutex_lock(&fpc->lock);
> +	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;
> +
> +	if (--fpc->counter_clk_enable)
> +		return;
> +
> +	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->counter_clk_en);
> +	clk_disable_unprepare(fpc->counter_clk);
> +}
> +
> +static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device
> +*pwm) {
> +	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
> +	u32 val;
> +
> +	val = readl(fpc->base + FTM_OUTMASK);
> +	val |= BIT(pwm->hwpwm);
> +	writel(val, fpc->base + FTM_OUTMASK);
> +
> +	mutex_lock(&fpc->lock);
> +
> +	fsl_counter_clock_disable(fpc);
> +
> +	val = readl(fpc->base + FTM_OUTMASK);
> +
> +	if ((val & 0xFF) == 0xFF) {
> +		fpc->period_ns = 0;
> +		fpc->counter_clk_en = NULL;
> +	}
> +
> +	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_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->sys_clk = devm_clk_get(&pdev->dev, "ftm_sys");
> +	if (IS_ERR(fpc->sys_clk)) {
> +		dev_err(&pdev->dev,
> +				"failed to get \"ftm_sys\" clock\n");
> +		return PTR_ERR(fpc->sys_clk);
> +	}
> +
> +	ret = clk_prepare_enable(fpc->sys_clk);
> +	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->sys_clk);
> +
> +	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 0;
> +}
> +
> +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@xxxxxxxxxxxxx>");
> +MODULE_ALIAS("platform:fsl-ftm-pwm");
> +MODULE_LICENSE("GPL");
> --
> 1.8.4
> 
> 
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