[linux.git] / drivers / pwm / pwm-imx-tpm.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2018-2019 NXP.
 *
 * Limitations:
 * - The TPM counter and period counter are shared between
 *   multiple channels, so all channels should use same period
 *   settings.
 * - Changes to polarity cannot be latched at the time of the
 *   next period start.
 * - Changing period and duty cycle together isn't atomic,
 *   with the wrong timing it might happen that a period is
 *   produced with old duty cycle but new period settings.
 */

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>

#define PWM_IMX_TPM_PARAM	0x4
#define PWM_IMX_TPM_GLOBAL	0x8
#define PWM_IMX_TPM_SC		0x10
#define PWM_IMX_TPM_CNT		0x14
#define PWM_IMX_TPM_MOD		0x18
#define PWM_IMX_TPM_CnSC(n)	(0x20 + (n) * 0x8)
#define PWM_IMX_TPM_CnV(n)	(0x24 + (n) * 0x8)

#define PWM_IMX_TPM_PARAM_CHAN			GENMASK(7, 0)

#define PWM_IMX_TPM_SC_PS			GENMASK(2, 0)
#define PWM_IMX_TPM_SC_CMOD			GENMASK(4, 3)
#define PWM_IMX_TPM_SC_CMOD_INC_EVERY_CLK	FIELD_PREP(PWM_IMX_TPM_SC_CMOD, 1)
#define PWM_IMX_TPM_SC_CPWMS			BIT(5)

#define PWM_IMX_TPM_CnSC_CHF	BIT(7)
#define PWM_IMX_TPM_CnSC_MSB	BIT(5)
#define PWM_IMX_TPM_CnSC_MSA	BIT(4)

/*
 * The reference manual describes this field as two separate bits. The
 * semantic of the two bits isn't orthogonal though, so they are treated
 * together as a 2-bit field here.
 */
#define PWM_IMX_TPM_CnSC_ELS	GENMASK(3, 2)
#define PWM_IMX_TPM_CnSC_ELS_INVERSED	FIELD_PREP(PWM_IMX_TPM_CnSC_ELS, 1)
#define PWM_IMX_TPM_CnSC_ELS_NORMAL	FIELD_PREP(PWM_IMX_TPM_CnSC_ELS, 2)


#define PWM_IMX_TPM_MOD_WIDTH	16
#define PWM_IMX_TPM_MOD_MOD	GENMASK(PWM_IMX_TPM_MOD_WIDTH - 1, 0)

struct imx_tpm_pwm_chip {
	struct pwm_chip chip;
	struct clk *clk;
	void __iomem *base;
	struct mutex lock;
	u32 user_count;
	u32 enable_count;
	u32 real_period;
};

struct imx_tpm_pwm_param {
	u8 prescale;
	u32 mod;
	u32 val;
};

static inline struct imx_tpm_pwm_chip *
to_imx_tpm_pwm_chip(struct pwm_chip *chip)
{
	return container_of(chip, struct imx_tpm_pwm_chip, chip);
}

/*
 * This function determines for a given pwm_state *state that a consumer
 * might request the pwm_state *real_state that eventually is implemented
 * by the hardware and the necessary register values (in *p) to achieve
 * this.
 */
static int pwm_imx_tpm_round_state(struct pwm_chip *chip,
				   struct imx_tpm_pwm_param *p,
				   struct pwm_state *real_state,
				   const struct pwm_state *state)
{
	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	u32 rate, prescale, period_count, clock_unit;
	u64 tmp;

	rate = clk_get_rate(tpm->clk);
	tmp = (u64)state->period * rate;
	clock_unit = DIV_ROUND_CLOSEST_ULL(tmp, NSEC_PER_SEC);
	if (clock_unit <= PWM_IMX_TPM_MOD_MOD)
		prescale = 0;
	else
		prescale = ilog2(clock_unit) + 1 - PWM_IMX_TPM_MOD_WIDTH;

	if ((!FIELD_FIT(PWM_IMX_TPM_SC_PS, prescale)))
		return -ERANGE;
	p->prescale = prescale;

	period_count = (clock_unit + ((1 << prescale) >> 1)) >> prescale;
	p->mod = period_count;

	/* calculate real period HW can support */
	tmp = (u64)period_count << prescale;
	tmp *= NSEC_PER_SEC;
	real_state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate);

	/*
	 * if eventually the PWM output is inactive, either
	 * duty cycle is 0 or status is disabled, need to
	 * make sure the output pin is inactive.
	 */
	if (!state->enabled)
		real_state->duty_cycle = 0;
	else
		real_state->duty_cycle = state->duty_cycle;

	tmp = (u64)p->mod * real_state->duty_cycle;
	p->val = DIV64_U64_ROUND_CLOSEST(tmp, real_state->period);

	real_state->polarity = state->polarity;
	real_state->enabled = state->enabled;

	return 0;
}

static void pwm_imx_tpm_get_state(struct pwm_chip *chip,
				  struct pwm_device *pwm,
				  struct pwm_state *state)
{
	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	u32 rate, val, prescale;
	u64 tmp;

	/* get period */
	state->period = tpm->real_period;

	/* get duty cycle */
	rate = clk_get_rate(tpm->clk);
	val = readl(tpm->base + PWM_IMX_TPM_SC);
	prescale = FIELD_GET(PWM_IMX_TPM_SC_PS, val);
	tmp = readl(tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm));
	tmp = (tmp << prescale) * NSEC_PER_SEC;
	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate);

	/* get polarity */
	val = readl(tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
	if ((val & PWM_IMX_TPM_CnSC_ELS) == PWM_IMX_TPM_CnSC_ELS_INVERSED)
		state->polarity = PWM_POLARITY_INVERSED;
	else
		/*
		 * Assume reserved values (2b00 and 2b11) to yield
		 * normal polarity.
		 */
		state->polarity = PWM_POLARITY_NORMAL;

	/* get channel status */
	state->enabled = FIELD_GET(PWM_IMX_TPM_CnSC_ELS, val) ? true : false;
}

/* this function is supposed to be called with mutex hold */
static int pwm_imx_tpm_apply_hw(struct pwm_chip *chip,
				struct imx_tpm_pwm_param *p,
				struct pwm_state *state,
				struct pwm_device *pwm)
{
	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	bool period_update = false;
	bool duty_update = false;
	u32 val, cmod, cur_prescale;
	unsigned long timeout;
	struct pwm_state c;

	if (state->period != tpm->real_period) {
		/*
		 * TPM counter is shared by multiple channels, so
		 * prescale and period can NOT be modified when
		 * there are multiple channels in use with different
		 * period settings.
		 */
		if (tpm->user_count > 1)
			return -EBUSY;

		val = readl(tpm->base + PWM_IMX_TPM_SC);
		cmod = FIELD_GET(PWM_IMX_TPM_SC_CMOD, val);
		cur_prescale = FIELD_GET(PWM_IMX_TPM_SC_PS, val);
		if (cmod && cur_prescale != p->prescale)
			return -EBUSY;

		/* set TPM counter prescale */
		val &= ~PWM_IMX_TPM_SC_PS;
		val |= FIELD_PREP(PWM_IMX_TPM_SC_PS, p->prescale);
		writel(val, tpm->base + PWM_IMX_TPM_SC);

		/*
		 * set period count:
		 * if the PWM is disabled (CMOD[1:0] = 2b00), then MOD register
		 * is updated when MOD register is written.
		 *
		 * if the PWM is enabled (CMOD[1:0] ≠ 2b00), the period length
		 * is latched into hardware when the next period starts.
		 */
		writel(p->mod, tpm->base + PWM_IMX_TPM_MOD);
		tpm->real_period = state->period;
		period_update = true;
	}

	pwm_imx_tpm_get_state(chip, pwm, &c);

	/* polarity is NOT allowed to be changed if PWM is active */
	if (c.enabled && c.polarity != state->polarity)
		return -EBUSY;

	if (state->duty_cycle != c.duty_cycle) {
		/*
		 * set channel value:
		 * if the PWM is disabled (CMOD[1:0] = 2b00), then CnV register
		 * is updated when CnV register is written.
		 *
		 * if the PWM is enabled (CMOD[1:0] ≠ 2b00), the duty length
		 * is latched into hardware when the next period starts.
		 */
		writel(p->val, tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm));
		duty_update = true;
	}

	/* make sure MOD & CnV registers are updated */
	if (period_update || duty_update) {
		timeout = jiffies + msecs_to_jiffies(tpm->real_period /
						     NSEC_PER_MSEC + 1);
		while (readl(tpm->base + PWM_IMX_TPM_MOD) != p->mod
		       || readl(tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm))
		       != p->val) {
			if (time_after(jiffies, timeout))
				return -ETIME;
			cpu_relax();
		}
	}

	/*
	 * polarity settings will enabled/disable output status
	 * immediately, so if the channel is disabled, need to
	 * make sure MSA/MSB/ELS are set to 0 which means channel
	 * disabled.
	 */
	val = readl(tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
	val &= ~(PWM_IMX_TPM_CnSC_ELS | PWM_IMX_TPM_CnSC_MSA |
		 PWM_IMX_TPM_CnSC_MSB);
	if (state->enabled) {
		/*
		 * set polarity (for edge-aligned PWM modes)
		 *
		 * ELS[1:0] = 2b10 yields normal polarity behaviour,
		 * ELS[1:0] = 2b01 yields inversed polarity.
		 * The other values are reserved.
		 */
		val |= PWM_IMX_TPM_CnSC_MSB;
		val |= (state->polarity == PWM_POLARITY_NORMAL) ?
			PWM_IMX_TPM_CnSC_ELS_NORMAL :
			PWM_IMX_TPM_CnSC_ELS_INVERSED;
	}
	writel(val, tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));

	/* control the counter status */
	if (state->enabled != c.enabled) {
		val = readl(tpm->base + PWM_IMX_TPM_SC);
		if (state->enabled) {
			if (++tpm->enable_count == 1)
				val |= PWM_IMX_TPM_SC_CMOD_INC_EVERY_CLK;
		} else {
			if (--tpm->enable_count == 0)
				val &= ~PWM_IMX_TPM_SC_CMOD;
		}
		writel(val, tpm->base + PWM_IMX_TPM_SC);
	}

	return 0;
}

static int pwm_imx_tpm_apply(struct pwm_chip *chip,
			     struct pwm_device *pwm,
			     const struct pwm_state *state)
{
	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	struct imx_tpm_pwm_param param;
	struct pwm_state real_state;
	int ret;

	ret = pwm_imx_tpm_round_state(chip, &param, &real_state, state);
	if (ret)
		return ret;

	mutex_lock(&tpm->lock);
	ret = pwm_imx_tpm_apply_hw(chip, &param, &real_state, pwm);
	mutex_unlock(&tpm->lock);

	return ret;
}

static int pwm_imx_tpm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);

	mutex_lock(&tpm->lock);
	tpm->user_count++;
	mutex_unlock(&tpm->lock);

	return 0;
}

static void pwm_imx_tpm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);

	mutex_lock(&tpm->lock);
	tpm->user_count--;
	mutex_unlock(&tpm->lock);
}

static const struct pwm_ops imx_tpm_pwm_ops = {
	.request = pwm_imx_tpm_request,
	.free = pwm_imx_tpm_free,
	.get_state = pwm_imx_tpm_get_state,
	.apply = pwm_imx_tpm_apply,
	.owner = THIS_MODULE,
};

static int pwm_imx_tpm_probe(struct platform_device *pdev)
{
	struct imx_tpm_pwm_chip *tpm;
	int ret;
	u32 val;

	tpm = devm_kzalloc(&pdev->dev, sizeof(*tpm), GFP_KERNEL);
	if (!tpm)
		return -ENOMEM;

	platform_set_drvdata(pdev, tpm);

	tpm->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(tpm->base))
		return PTR_ERR(tpm->base);

	tpm->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(tpm->clk))
		return dev_err_probe(&pdev->dev, PTR_ERR(tpm->clk),
				     "failed to get PWM clock\n");

	ret = clk_prepare_enable(tpm->clk);
	if (ret) {
		dev_err(&pdev->dev,
			"failed to prepare or enable clock: %d\n", ret);
		return ret;
	}

	tpm->chip.dev = &pdev->dev;
	tpm->chip.ops = &imx_tpm_pwm_ops;

	/* get number of channels */
	val = readl(tpm->base + PWM_IMX_TPM_PARAM);
	tpm->chip.npwm = FIELD_GET(PWM_IMX_TPM_PARAM_CHAN, val);

	mutex_init(&tpm->lock);

	ret = pwmchip_add(&tpm->chip);
	if (ret) {
		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
		clk_disable_unprepare(tpm->clk);
	}

	return ret;
}

static int pwm_imx_tpm_remove(struct platform_device *pdev)
{
	struct imx_tpm_pwm_chip *tpm = platform_get_drvdata(pdev);

	pwmchip_remove(&tpm->chip);

	clk_disable_unprepare(tpm->clk);

	return 0;
}

static int __maybe_unused pwm_imx_tpm_suspend(struct device *dev)
{
	struct imx_tpm_pwm_chip *tpm = dev_get_drvdata(dev);

	if (tpm->enable_count > 0)
		return -EBUSY;

	clk_disable_unprepare(tpm->clk);

	return 0;
}

static int __maybe_unused pwm_imx_tpm_resume(struct device *dev)
{
	struct imx_tpm_pwm_chip *tpm = dev_get_drvdata(dev);
	int ret = 0;

	ret = clk_prepare_enable(tpm->clk);
	if (ret)
		dev_err(dev, "failed to prepare or enable clock: %d\n", ret);

	return ret;
}

static SIMPLE_DEV_PM_OPS(imx_tpm_pwm_pm,
			 pwm_imx_tpm_suspend, pwm_imx_tpm_resume);

static const struct of_device_id imx_tpm_pwm_dt_ids[] = {
	{ .compatible = "fsl,imx7ulp-pwm", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_tpm_pwm_dt_ids);

static struct platform_driver imx_tpm_pwm_driver = {
	.driver = {
		.name = "imx7ulp-tpm-pwm",
		.of_match_table = imx_tpm_pwm_dt_ids,
		.pm = &imx_tpm_pwm_pm,
	},
	.probe	= pwm_imx_tpm_probe,
	.remove = pwm_imx_tpm_remove,
};
module_platform_driver(imx_tpm_pwm_driver);

MODULE_AUTHOR("Anson Huang <[email protected]>");
MODULE_DESCRIPTION("i.MX TPM PWM Driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
738a1cfe AH	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Copyright 2018-2019 NXP.
	4	*
	5	* Limitations:
	6	* - The TPM counter and period counter are shared between
	7	* multiple channels, so all channels should use same period
	8	* settings.
	9	* - Changes to polarity cannot be latched at the time of the
	10	* next period start.
	11	* - Changing period and duty cycle together isn't atomic,
	12	* with the wrong timing it might happen that a period is
	13	* produced with old duty cycle but new period settings.
	14	*/
	15
	16	#include <linux/bitfield.h>
	17	#include <linux/bitops.h>
	18	#include <linux/clk.h>
	19	#include <linux/err.h>
	20	#include <linux/io.h>
738a1cfe AH	21	#include <linux/module.h>
738a1cfe AH	22	#include <linux/of.h>
738a1cfe AH	23	#include <linux/platform_device.h>
	24	#include <linux/pwm.h>
	25	#include <linux/slab.h>
	26
	27	#define PWM_IMX_TPM_PARAM 0x4
	28	#define PWM_IMX_TPM_GLOBAL 0x8
	29	#define PWM_IMX_TPM_SC 0x10
	30	#define PWM_IMX_TPM_CNT 0x14
	31	#define PWM_IMX_TPM_MOD 0x18
	32	#define PWM_IMX_TPM_CnSC(n) (0x20 + (n) * 0x8)
	33	#define PWM_IMX_TPM_CnV(n) (0x24 + (n) * 0x8)
	34
	35	#define PWM_IMX_TPM_PARAM_CHAN GENMASK(7, 0)
	36
	37	#define PWM_IMX_TPM_SC_PS GENMASK(2, 0)
	38	#define PWM_IMX_TPM_SC_CMOD GENMASK(4, 3)
	39	#define PWM_IMX_TPM_SC_CMOD_INC_EVERY_CLK FIELD_PREP(PWM_IMX_TPM_SC_CMOD, 1)
	40	#define PWM_IMX_TPM_SC_CPWMS BIT(5)
	41
	42	#define PWM_IMX_TPM_CnSC_CHF BIT(7)
	43	#define PWM_IMX_TPM_CnSC_MSB BIT(5)
	44	#define PWM_IMX_TPM_CnSC_MSA BIT(4)
	45
	46	/*
	47	* The reference manual describes this field as two separate bits. The
	48	* semantic of the two bits isn't orthogonal though, so they are treated
	49	* together as a 2-bit field here.
	50	*/
	51	#define PWM_IMX_TPM_CnSC_ELS GENMASK(3, 2)
	52	#define PWM_IMX_TPM_CnSC_ELS_INVERSED FIELD_PREP(PWM_IMX_TPM_CnSC_ELS, 1)
	53	#define PWM_IMX_TPM_CnSC_ELS_NORMAL FIELD_PREP(PWM_IMX_TPM_CnSC_ELS, 2)
	54
	55
	56	#define PWM_IMX_TPM_MOD_WIDTH 16
	57	#define PWM_IMX_TPM_MOD_MOD GENMASK(PWM_IMX_TPM_MOD_WIDTH - 1, 0)
	58
	59	struct imx_tpm_pwm_chip {
	60	struct pwm_chip chip;
	61	struct clk *clk;
	62	void __iomem *base;
	63	struct mutex lock;
	64	u32 user_count;
	65	u32 enable_count;
	66	u32 real_period;
	67	};
	68
	69	struct imx_tpm_pwm_param {
	70	u8 prescale;
	71	u32 mod;
	72	u32 val;
	73	};
	74
	75	static inline struct imx_tpm_pwm_chip *
	76	to_imx_tpm_pwm_chip(struct pwm_chip *chip)
	77	{
	78	return container_of(chip, struct imx_tpm_pwm_chip, chip);
	79	}
	80
	81	/*
	82	* This function determines for a given pwm_state *state that a consumer
	83	* might request the pwm_state *real_state that eventually is implemented
	84	* by the hardware and the necessary register values (in *p) to achieve
	85	* this.
	86	*/
87	static int pwm_imx_tpm_round_state(struct pwm_chip *chip,
88	struct imx_tpm_pwm_param *p,
89	struct pwm_state *real_state,
71523d18	90	const struct pwm_state *state)
738a1cfe AH	91	{
	92	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	93	u32 rate, prescale, period_count, clock_unit;
	94	u64 tmp;
	95
	96	rate = clk_get_rate(tpm->clk);
	97	tmp = (u64)state->period * rate;
	98	clock_unit = DIV_ROUND_CLOSEST_ULL(tmp, NSEC_PER_SEC);
	99	if (clock_unit <= PWM_IMX_TPM_MOD_MOD)
	100	prescale = 0;
	101	else
	102	prescale = ilog2(clock_unit) + 1 - PWM_IMX_TPM_MOD_WIDTH;
	103
	104	if ((!FIELD_FIT(PWM_IMX_TPM_SC_PS, prescale)))
	105	return -ERANGE;
	106	p->prescale = prescale;
	107
	108	period_count = (clock_unit + ((1 << prescale) >> 1)) >> prescale;
	109	p->mod = period_count;
	110
	111	/* calculate real period HW can support */
	112	tmp = (u64)period_count << prescale;
	113	tmp *= NSEC_PER_SEC;
	114	real_state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate);
	115
	116	/*
	117	* if eventually the PWM output is inactive, either
	118	* duty cycle is 0 or status is disabled, need to
	119	* make sure the output pin is inactive.
	120	*/
	121	if (!state->enabled)
	122	real_state->duty_cycle = 0;
	123	else
	124	real_state->duty_cycle = state->duty_cycle;
	125
	126	tmp = (u64)p->mod * real_state->duty_cycle;
fcdea6b2	127	p->val = DIV64_U64_ROUND_CLOSEST(tmp, real_state->period);
738a1cfe AH	128
	129	real_state->polarity = state->polarity;
	130	real_state->enabled = state->enabled;
	131
	132	return 0;
	133	}
	134
	135	static void pwm_imx_tpm_get_state(struct pwm_chip *chip,
	136	struct pwm_device *pwm,
	137	struct pwm_state *state)
	138	{
	139	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	140	u32 rate, val, prescale;
	141	u64 tmp;
	142
	143	/* get period */
	144	state->period = tpm->real_period;
	145
	146	/* get duty cycle */
	147	rate = clk_get_rate(tpm->clk);
	148	val = readl(tpm->base + PWM_IMX_TPM_SC);
	149	prescale = FIELD_GET(PWM_IMX_TPM_SC_PS, val);
	150	tmp = readl(tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm));
	151	tmp = (tmp << prescale) * NSEC_PER_SEC;
	152	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate);
	153
	154	/* get polarity */
	155	val = readl(tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
	156	if ((val & PWM_IMX_TPM_CnSC_ELS) == PWM_IMX_TPM_CnSC_ELS_INVERSED)
	157	state->polarity = PWM_POLARITY_INVERSED;
	158	else
	159	/*
	160	* Assume reserved values (2b00 and 2b11) to yield
	161	* normal polarity.
	162	*/
	163	state->polarity = PWM_POLARITY_NORMAL;
	164
	165	/* get channel status */
	166	state->enabled = FIELD_GET(PWM_IMX_TPM_CnSC_ELS, val) ? true : false;
	167	}
	168
	169	/* this function is supposed to be called with mutex hold */
	170	static int pwm_imx_tpm_apply_hw(struct pwm_chip *chip,
	171	struct imx_tpm_pwm_param *p,
	172	struct pwm_state *state,
	173	struct pwm_device *pwm)
	174	{
	175	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	176	bool period_update = false;
	177	bool duty_update = false;
	178	u32 val, cmod, cur_prescale;
	179	unsigned long timeout;
	180	struct pwm_state c;
	181
	182	if (state->period != tpm->real_period) {
	183	/*
	184	* TPM counter is shared by multiple channels, so
	185	* prescale and period can NOT be modified when
	186	* there are multiple channels in use with different
	187	* period settings.
	188	*/
	189	if (tpm->user_count > 1)
	190	return -EBUSY;
	191
192	val = readl(tpm->base + PWM_IMX_TPM_SC);
193	cmod = FIELD_GET(PWM_IMX_TPM_SC_CMOD, val);
194	cur_prescale = FIELD_GET(PWM_IMX_TPM_SC_PS, val);
195	if (cmod && cur_prescale != p->prescale)
196	return -EBUSY;
197
198	/* set TPM counter prescale */
199	val &= ~PWM_IMX_TPM_SC_PS;
200	val \|= FIELD_PREP(PWM_IMX_TPM_SC_PS, p->prescale);
201	writel(val, tpm->base + PWM_IMX_TPM_SC);
202
203	/*
204	* set period count:
205	* if the PWM is disabled (CMOD[1:0] = 2b00), then MOD register
206	* is updated when MOD register is written.
207	*
208	* if the PWM is enabled (CMOD[1:0] ≠ 2b00), the period length
209	* is latched into hardware when the next period starts.
210	*/
211	writel(p->mod, tpm->base + PWM_IMX_TPM_MOD);
212	tpm->real_period = state->period;
213	period_update = true;
214	}
215
216	pwm_imx_tpm_get_state(chip, pwm, &c);
217
218	/* polarity is NOT allowed to be changed if PWM is active */
219	if (c.enabled && c.polarity != state->polarity)
220	return -EBUSY;
221
222	if (state->duty_cycle != c.duty_cycle) {
223	/*
224	* set channel value:
225	* if the PWM is disabled (CMOD[1:0] = 2b00), then CnV register
226	* is updated when CnV register is written.
227	*
228	* if the PWM is enabled (CMOD[1:0] ≠ 2b00), the duty length
229	* is latched into hardware when the next period starts.
230	*/
231	writel(p->val, tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm));
232	duty_update = true;
233	}
234
235	/* make sure MOD & CnV registers are updated */
236	if (period_update \|\| duty_update) {
237	timeout = jiffies + msecs_to_jiffies(tpm->real_period /
238	NSEC_PER_MSEC + 1);
239	while (readl(tpm->base + PWM_IMX_TPM_MOD) != p->mod
240	\|\| readl(tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm))
241	!= p->val) {
242	if (time_after(jiffies, timeout))
243	return -ETIME;
244	cpu_relax();
245	}
246	}
247
248	/*
249	* polarity settings will enabled/disable output status
250	* immediately, so if the channel is disabled, need to
251	* make sure MSA/MSB/ELS are set to 0 which means channel
252	* disabled.
253	*/
254	val = readl(tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
255	val &= ~(PWM_IMX_TPM_CnSC_ELS \| PWM_IMX_TPM_CnSC_MSA \|
256	PWM_IMX_TPM_CnSC_MSB);
257	if (state->enabled) {
258	/*
259	* set polarity (for edge-aligned PWM modes)
260	*
261	* ELS[1:0] = 2b10 yields normal polarity behaviour,
262	* ELS[1:0] = 2b01 yields inversed polarity.
263	* The other values are reserved.
264	*/
265	val \|= PWM_IMX_TPM_CnSC_MSB;
266	val \|= (state->polarity == PWM_POLARITY_NORMAL) ?
267	PWM_IMX_TPM_CnSC_ELS_NORMAL :
268	PWM_IMX_TPM_CnSC_ELS_INVERSED;
269	}
270	writel(val, tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
271
272	/* control the counter status */
273	if (state->enabled != c.enabled) {
274	val = readl(tpm->base + PWM_IMX_TPM_SC);
275	if (state->enabled) {
276	if (++tpm->enable_count == 1)
277	val \|= PWM_IMX_TPM_SC_CMOD_INC_EVERY_CLK;
278	} else {
279	if (--tpm->enable_count == 0)
280	val &= ~PWM_IMX_TPM_SC_CMOD;
281	}
282	writel(val, tpm->base + PWM_IMX_TPM_SC);
283	}
284
285	return 0;
286	}
287
288	static int pwm_imx_tpm_apply(struct pwm_chip *chip,
289	struct pwm_device *pwm,
71523d18	290	const struct pwm_state *state)
738a1cfe AH	291	{
	292	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	293	struct imx_tpm_pwm_param param;
	294	struct pwm_state real_state;
	295	int ret;
	296
	297	ret = pwm_imx_tpm_round_state(chip, &param, &real_state, state);
	298	if (ret)
	299	return ret;
	300
	301	mutex_lock(&tpm->lock);
	302	ret = pwm_imx_tpm_apply_hw(chip, &param, &real_state, pwm);
	303	mutex_unlock(&tpm->lock);
	304
	305	return ret;
	306	}
	307
	308	static int pwm_imx_tpm_request(struct pwm_chip chip, struct pwm_device pwm)
	309	{
	310	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	311
	312	mutex_lock(&tpm->lock);
	313	tpm->user_count++;
	314	mutex_unlock(&tpm->lock);
	315
	316	return 0;
	317	}
	318
	319	static void pwm_imx_tpm_free(struct pwm_chip chip, struct pwm_device pwm)
	320	{
	321	struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
	322
	323	mutex_lock(&tpm->lock);
	324	tpm->user_count--;
	325	mutex_unlock(&tpm->lock);
	326	}
	327
	328	static const struct pwm_ops imx_tpm_pwm_ops = {
	329	.request = pwm_imx_tpm_request,
	330	.free = pwm_imx_tpm_free,
	331	.get_state = pwm_imx_tpm_get_state,
	332	.apply = pwm_imx_tpm_apply,
	333	.owner = THIS_MODULE,
	334	};
	335
	336	static int pwm_imx_tpm_probe(struct platform_device *pdev)
	337	{
	338	struct imx_tpm_pwm_chip *tpm;
	339	int ret;
	340	u32 val;
	341
	342	tpm = devm_kzalloc(&pdev->dev, sizeof(*tpm), GFP_KERNEL);
	343	if (!tpm)
	344	return -ENOMEM;
	345
	346	platform_set_drvdata(pdev, tpm);
	347
	348	tpm->base = devm_platform_ioremap_resource(pdev, 0);
	349	if (IS_ERR(tpm->base))
	350	return PTR_ERR(tpm->base);
	351
	352	tpm->clk = devm_clk_get(&pdev->dev, NULL);
168cc329 AH	353	if (IS_ERR(tpm->clk))
	354	return dev_err_probe(&pdev->dev, PTR_ERR(tpm->clk),
	355	"failed to get PWM clock\n");
738a1cfe AH	356
	357	ret = clk_prepare_enable(tpm->clk);
	358	if (ret) {
	359	dev_err(&pdev->dev,
	360	"failed to prepare or enable clock: %d\n", ret);
	361	return ret;
	362	}
	363
	364	tpm->chip.dev = &pdev->dev;
	365	tpm->chip.ops = &imx_tpm_pwm_ops;
738a1cfe AH	366
	367	/* get number of channels */
	368	val = readl(tpm->base + PWM_IMX_TPM_PARAM);
	369	tpm->chip.npwm = FIELD_GET(PWM_IMX_TPM_PARAM_CHAN, val);
	370
	371	mutex_init(&tpm->lock);
	372
	373	ret = pwmchip_add(&tpm->chip);
	374	if (ret) {
	375	dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
	376	clk_disable_unprepare(tpm->clk);
	377	}
	378
	379	return ret;
	380	}
	381
	382	static int pwm_imx_tpm_remove(struct platform_device *pdev)
	383	{
	384	struct imx_tpm_pwm_chip *tpm = platform_get_drvdata(pdev);
bfecbc94 UKK	385
bfecbc94 UKK	386	pwmchip_remove(&tpm->chip);
738a1cfe AH	387
	388	clk_disable_unprepare(tpm->clk);
	389
bfecbc94	390	return 0;
738a1cfe AH	391	}
	392
	393	static int __maybe_unused pwm_imx_tpm_suspend(struct device *dev)
	394	{
	395	struct imx_tpm_pwm_chip *tpm = dev_get_drvdata(dev);
	396
	397	if (tpm->enable_count > 0)
	398	return -EBUSY;
	399
	400	clk_disable_unprepare(tpm->clk);
	401
	402	return 0;
	403	}
	404
	405	static int __maybe_unused pwm_imx_tpm_resume(struct device *dev)
	406	{
	407	struct imx_tpm_pwm_chip *tpm = dev_get_drvdata(dev);
	408	int ret = 0;
	409
	410	ret = clk_prepare_enable(tpm->clk);
	411	if (ret)
5a43c201	412	dev_err(dev, "failed to prepare or enable clock: %d\n", ret);
738a1cfe AH	413
	414	return ret;
	415	}
	416
	417	static SIMPLE_DEV_PM_OPS(imx_tpm_pwm_pm,
	418	pwm_imx_tpm_suspend, pwm_imx_tpm_resume);
	419
	420	static const struct of_device_id imx_tpm_pwm_dt_ids[] = {
	421	{ .compatible = "fsl,imx7ulp-pwm", },
	422	{ /* sentinel */ }
	423	};
	424	MODULE_DEVICE_TABLE(of, imx_tpm_pwm_dt_ids);
	425
	426	static struct platform_driver imx_tpm_pwm_driver = {
	427	.driver = {
	428	.name = "imx7ulp-tpm-pwm",
	429	.of_match_table = imx_tpm_pwm_dt_ids,
	430	.pm = &imx_tpm_pwm_pm,
	431	},
	432	.probe = pwm_imx_tpm_probe,
	433	.remove = pwm_imx_tpm_remove,
	434	};
	435	module_platform_driver(imx_tpm_pwm_driver);
	436
	437	MODULE_AUTHOR("Anson Huang <[email protected]>");
	438	MODULE_DESCRIPTION("i.MX TPM PWM Driver");
	439	MODULE_LICENSE("GPL v2");