[linux-block.git] / drivers / pwm / pwm-stmpe.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2016 Linaro Ltd.
 *
 * Author: Linus Walleij <linus.walleij@linaro.org>
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/mfd/stmpe.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>

#define STMPE24XX_PWMCS		0x30
#define PWMCS_EN_PWM0		BIT(0)
#define PWMCS_EN_PWM1		BIT(1)
#define PWMCS_EN_PWM2		BIT(2)
#define STMPE24XX_PWMIC0	0x38
#define STMPE24XX_PWMIC1	0x39
#define STMPE24XX_PWMIC2	0x3a

#define STMPE_PWM_24XX_PINBASE	21

struct stmpe_pwm {
	struct stmpe *stmpe;
	struct pwm_chip chip;
	u8 last_duty;
};

static inline struct stmpe_pwm *to_stmpe_pwm(struct pwm_chip *chip)
{
	return container_of(chip, struct stmpe_pwm, chip);
}

static int stmpe_24xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
	u8 value;
	int ret;

	ret = stmpe_reg_read(stmpe_pwm->stmpe, STMPE24XX_PWMCS);
	if (ret < 0) {
		dev_err(chip->dev, "error reading PWM#%u control\n",
			pwm->hwpwm);
		return ret;
	}

	value = ret | BIT(pwm->hwpwm);

	ret = stmpe_reg_write(stmpe_pwm->stmpe, STMPE24XX_PWMCS, value);
	if (ret) {
		dev_err(chip->dev, "error writing PWM#%u control\n",
			pwm->hwpwm);
		return ret;
	}

	return 0;
}

static void stmpe_24xx_pwm_disable(struct pwm_chip *chip,
				   struct pwm_device *pwm)
{
	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
	u8 value;
	int ret;

	ret = stmpe_reg_read(stmpe_pwm->stmpe, STMPE24XX_PWMCS);
	if (ret < 0) {
		dev_err(chip->dev, "error reading PWM#%u control\n",
			pwm->hwpwm);
		return;
	}

	value = ret & ~BIT(pwm->hwpwm);

	ret = stmpe_reg_write(stmpe_pwm->stmpe, STMPE24XX_PWMCS, value);
	if (ret) {
		dev_err(chip->dev, "error writing PWM#%u control\n",
			pwm->hwpwm);
		return;
	}
}

/* STMPE 24xx PWM instructions */
#define SMAX		0x007f
#define SMIN		0x00ff
#define GTS		0x0000
#define LOAD		BIT(14) /* Only available on 2403 */
#define RAMPUP		0x0000
#define RAMPDOWN	BIT(7)
#define PRESCALE_512	BIT(14)
#define STEPTIME_1	BIT(8)
#define BRANCH		(BIT(15) | BIT(13))

static int stmpe_24xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
				 int duty_ns, int period_ns)
{
	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
	unsigned int i, pin;
	u16 program[3] = {
		SMAX,
		GTS,
		GTS,
	};
	u8 offset;
	int ret;

	/* Make sure we are disabled */
	if (pwm_is_enabled(pwm)) {
		stmpe_24xx_pwm_disable(chip, pwm);
	} else {
		/* Connect the PWM to the pin */
		pin = pwm->hwpwm;

		/* On STMPE2401 and 2403 pins 21,22,23 are used */
		if (stmpe_pwm->stmpe->partnum == STMPE2401 ||
		    stmpe_pwm->stmpe->partnum == STMPE2403)
			pin += STMPE_PWM_24XX_PINBASE;

		ret = stmpe_set_altfunc(stmpe_pwm->stmpe, BIT(pin),
					STMPE_BLOCK_PWM);
		if (ret) {
			dev_err(chip->dev, "unable to connect PWM#%u to pin\n",
				pwm->hwpwm);
			return ret;
		}
	}

	/* STMPE24XX */
	switch (pwm->hwpwm) {
	case 0:
		offset = STMPE24XX_PWMIC0;
		break;

	case 1:
		offset = STMPE24XX_PWMIC1;
		break;

	case 2:
		offset = STMPE24XX_PWMIC2;
		break;

	default:
		/* Should not happen as npwm is 3 */
		return -ENODEV;
	}

	dev_dbg(chip->dev, "PWM#%u: config duty %d ns, period %d ns\n",
		pwm->hwpwm, duty_ns, period_ns);

	if (duty_ns == 0) {
		if (stmpe_pwm->stmpe->partnum == STMPE2401)
			program[0] = SMAX; /* off all the time */

		if (stmpe_pwm->stmpe->partnum == STMPE2403)
			program[0] = LOAD | 0xff; /* LOAD 0xff */

		stmpe_pwm->last_duty = 0x00;
	} else if (duty_ns == period_ns) {
		if (stmpe_pwm->stmpe->partnum == STMPE2401)
			program[0] = SMIN; /* on all the time */

		if (stmpe_pwm->stmpe->partnum == STMPE2403)
			program[0] = LOAD | 0x00; /* LOAD 0x00 */

		stmpe_pwm->last_duty = 0xff;
	} else {
		u8 value, last = stmpe_pwm->last_duty;
		unsigned long duty;

		/*
		 * Counter goes from 0x00 to 0xff repeatedly at 32768 Hz,
		 * (means a period of 30517 ns) then this is compared to the
		 * counter from the ramp, if this is >= PWM counter the output
		 * is high. With LOAD we can define how much of the cycle it
		 * is on.
		 *
		 * Prescale = 0 -> 2 kHz -> T = 1/f = 488281.25 ns
		 */

		/* Scale to 0..0xff */
		duty = duty_ns * 256;
		duty = DIV_ROUND_CLOSEST(duty, period_ns);
		value = duty;

		if (value == last) {
			/* Run the old program */
			if (pwm_is_enabled(pwm))
				stmpe_24xx_pwm_enable(chip, pwm);

			return 0;
		} else if (stmpe_pwm->stmpe->partnum == STMPE2403) {
			/* STMPE2403 can simply set the right PWM value */
			program[0] = LOAD | value;
			program[1] = 0x0000;
		} else if (stmpe_pwm->stmpe->partnum == STMPE2401) {
			/* STMPE2401 need a complex program */
			u16 incdec = 0x0000;

			if (last < value)
				/* Count up */
				incdec = RAMPUP | (value - last);
			else
				/* Count down */
				incdec = RAMPDOWN | (last - value);

			/* Step to desired value, smoothly */
			program[0] = PRESCALE_512 | STEPTIME_1 | incdec;

			/* Loop eternally to 0x00 */
			program[1] = BRANCH;
		}

		dev_dbg(chip->dev,
			"PWM#%u: value = %02x, last_duty = %02x, program=%04x,%04x,%04x\n",
			pwm->hwpwm, value, last, program[0], program[1],
			program[2]);
		stmpe_pwm->last_duty = value;
	}

	/*
	 * We can write programs of up to 64 16-bit words into this channel.
	 */
	for (i = 0; i < ARRAY_SIZE(program); i++) {
		u8 value;

		value = (program[i] >> 8) & 0xff;

		ret = stmpe_reg_write(stmpe_pwm->stmpe, offset, value);
		if (ret) {
			dev_err(chip->dev, "error writing register %02x: %d\n",
				offset, ret);
			return ret;
		}

		value = program[i] & 0xff;

		ret = stmpe_reg_write(stmpe_pwm->stmpe, offset, value);
		if (ret) {
			dev_err(chip->dev, "error writing register %02x: %d\n",
				offset, ret);
			return ret;
		}
	}

	/* If we were enabled, re-enable this PWM */
	if (pwm_is_enabled(pwm))
		stmpe_24xx_pwm_enable(chip, pwm);

	/* Sleep for 200ms so we're sure it will take effect */
	msleep(200);

	dev_dbg(chip->dev, "programmed PWM#%u, %u bytes\n", pwm->hwpwm, i);

	return 0;
}

static int stmpe_24xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
				const struct pwm_state *state)
{
	int err;

	if (state->polarity != PWM_POLARITY_NORMAL)
		return -EINVAL;

	if (!state->enabled) {
		if (pwm->state.enabled)
			stmpe_24xx_pwm_disable(chip, pwm);

		return 0;
	}

	err = stmpe_24xx_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
	if (err)
		return err;

	if (!pwm->state.enabled)
		err = stmpe_24xx_pwm_enable(chip, pwm);

	return err;
}

static const struct pwm_ops stmpe_24xx_pwm_ops = {
	.apply = stmpe_24xx_pwm_apply,
	.owner = THIS_MODULE,
};

static int __init stmpe_pwm_probe(struct platform_device *pdev)
{
	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
	struct stmpe_pwm *stmpe_pwm;
	int ret;

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

	stmpe_pwm->stmpe = stmpe;
	stmpe_pwm->chip.dev = &pdev->dev;

	if (stmpe->partnum == STMPE2401 || stmpe->partnum == STMPE2403) {
		stmpe_pwm->chip.ops = &stmpe_24xx_pwm_ops;
		stmpe_pwm->chip.npwm = 3;
	} else {
		if (stmpe->partnum == STMPE1601)
			dev_err(&pdev->dev, "STMPE1601 not yet supported\n");
		else
			dev_err(&pdev->dev, "Unknown STMPE PWM\n");

		return -ENODEV;
	}

	ret = stmpe_enable(stmpe, STMPE_BLOCK_PWM);
	if (ret)
		return ret;

	ret = pwmchip_add(&stmpe_pwm->chip);
	if (ret) {
		stmpe_disable(stmpe, STMPE_BLOCK_PWM);
		return ret;
	}

	return 0;
}

static struct platform_driver stmpe_pwm_driver = {
	.driver = {
		.name = "stmpe-pwm",
	},
};
builtin_platform_driver_probe(stmpe_pwm_driver, stmpe_pwm_probe);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
ef1f09ec LW	2	/*
	3	* Copyright (C) 2016 Linaro Ltd.
	4	*
	5	* Author: Linus Walleij <linus.walleij@linaro.org>
ef1f09ec LW	6	*/
	7
	8	#include <linux/bitops.h>
	9	#include <linux/delay.h>
	10	#include <linux/err.h>
	11	#include <linux/mfd/stmpe.h>
	12	#include <linux/module.h>
	13	#include <linux/of.h>
	14	#include <linux/platform_device.h>
	15	#include <linux/pwm.h>
	16	#include <linux/slab.h>
	17
	18	#define STMPE24XX_PWMCS 0x30
	19	#define PWMCS_EN_PWM0 BIT(0)
	20	#define PWMCS_EN_PWM1 BIT(1)
	21	#define PWMCS_EN_PWM2 BIT(2)
	22	#define STMPE24XX_PWMIC0 0x38
	23	#define STMPE24XX_PWMIC1 0x39
	24	#define STMPE24XX_PWMIC2 0x3a
	25
	26	#define STMPE_PWM_24XX_PINBASE 21
	27
	28	struct stmpe_pwm {
	29	struct stmpe *stmpe;
	30	struct pwm_chip chip;
	31	u8 last_duty;
	32	};
	33
	34	static inline struct stmpe_pwm to_stmpe_pwm(struct pwm_chip chip)
	35	{
	36	return container_of(chip, struct stmpe_pwm, chip);
	37	}
	38
	39	static int stmpe_24xx_pwm_enable(struct pwm_chip chip, struct pwm_device pwm)
	40	{
	41	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
	42	u8 value;
	43	int ret;
	44
	45	ret = stmpe_reg_read(stmpe_pwm->stmpe, STMPE24XX_PWMCS);
	46	if (ret < 0) {
	47	dev_err(chip->dev, "error reading PWM#%u control\n",
	48	pwm->hwpwm);
	49	return ret;
	50	}
	51
	52	value = ret \| BIT(pwm->hwpwm);
	53
	54	ret = stmpe_reg_write(stmpe_pwm->stmpe, STMPE24XX_PWMCS, value);
	55	if (ret) {
	56	dev_err(chip->dev, "error writing PWM#%u control\n",
	57	pwm->hwpwm);
	58	return ret;
	59	}
	60
	61	return 0;
	62	}
	63
	64	static void stmpe_24xx_pwm_disable(struct pwm_chip *chip,
	65	struct pwm_device *pwm)
	66	{
	67	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
	68	u8 value;
	69	int ret;
70
71	ret = stmpe_reg_read(stmpe_pwm->stmpe, STMPE24XX_PWMCS);
72	if (ret < 0) {
73	dev_err(chip->dev, "error reading PWM#%u control\n",
74	pwm->hwpwm);
75	return;
76	}
77
78	value = ret & ~BIT(pwm->hwpwm);
79
80	ret = stmpe_reg_write(stmpe_pwm->stmpe, STMPE24XX_PWMCS, value);
81	if (ret) {
82	dev_err(chip->dev, "error writing PWM#%u control\n",
83	pwm->hwpwm);
84	return;
85	}
86	}
87
88	/* STMPE 24xx PWM instructions */
89	#define SMAX 0x007f
90	#define SMIN 0x00ff
91	#define GTS 0x0000
92	#define LOAD BIT(14) /* Only available on 2403 */
93	#define RAMPUP 0x0000
94	#define RAMPDOWN BIT(7)
95	#define PRESCALE_512 BIT(14)
96	#define STEPTIME_1 BIT(8)
97	#define BRANCH (BIT(15) \| BIT(13))
98
99	static int stmpe_24xx_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
100	int duty_ns, int period_ns)
101	{
102	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
103	unsigned int i, pin;
104	u16 program[3] = {
105	SMAX,
106	GTS,
107	GTS,
108	};
109	u8 offset;
110	int ret;
111
112	/* Make sure we are disabled */
113	if (pwm_is_enabled(pwm)) {
114	stmpe_24xx_pwm_disable(chip, pwm);
115	} else {
116	/* Connect the PWM to the pin */
117	pin = pwm->hwpwm;
118
119	/* On STMPE2401 and 2403 pins 21,22,23 are used */
120	if (stmpe_pwm->stmpe->partnum == STMPE2401 \|\|
121	stmpe_pwm->stmpe->partnum == STMPE2403)
122	pin += STMPE_PWM_24XX_PINBASE;
123
124	ret = stmpe_set_altfunc(stmpe_pwm->stmpe, BIT(pin),
125	STMPE_BLOCK_PWM);
126	if (ret) {
127	dev_err(chip->dev, "unable to connect PWM#%u to pin\n",
128	pwm->hwpwm);
129	return ret;
130	}
131	}
132
133	/* STMPE24XX */
134	switch (pwm->hwpwm) {
135	case 0:
136	offset = STMPE24XX_PWMIC0;
137	break;
138
139	case 1:
140	offset = STMPE24XX_PWMIC1;
141	break;
142
143	case 2:
8472b529	144	offset = STMPE24XX_PWMIC2;
ef1f09ec LW	145	break;
	146
	147	default:
	148	/* Should not happen as npwm is 3 */
	149	return -ENODEV;
	150	}
	151
	152	dev_dbg(chip->dev, "PWM#%u: config duty %d ns, period %d ns\n",
	153	pwm->hwpwm, duty_ns, period_ns);
	154
	155	if (duty_ns == 0) {
	156	if (stmpe_pwm->stmpe->partnum == STMPE2401)
	157	program[0] = SMAX; /* off all the time */
	158
	159	if (stmpe_pwm->stmpe->partnum == STMPE2403)
	160	program[0] = LOAD \| 0xff; /* LOAD 0xff */
	161
	162	stmpe_pwm->last_duty = 0x00;
	163	} else if (duty_ns == period_ns) {
	164	if (stmpe_pwm->stmpe->partnum == STMPE2401)
	165	program[0] = SMIN; /* on all the time */
	166
	167	if (stmpe_pwm->stmpe->partnum == STMPE2403)
	168	program[0] = LOAD \| 0x00; /* LOAD 0x00 */
	169
	170	stmpe_pwm->last_duty = 0xff;
	171	} else {
	172	u8 value, last = stmpe_pwm->last_duty;
	173	unsigned long duty;
	174
	175	/*
	176	* Counter goes from 0x00 to 0xff repeatedly at 32768 Hz,
	177	* (means a period of 30517 ns) then this is compared to the
	178	* counter from the ramp, if this is >= PWM counter the output
	179	* is high. With LOAD we can define how much of the cycle it
	180	* is on.
	181	*
	182	* Prescale = 0 -> 2 kHz -> T = 1/f = 488281.25 ns
	183	*/
	184
	185	/* Scale to 0..0xff */
	186	duty = duty_ns * 256;
	187	duty = DIV_ROUND_CLOSEST(duty, period_ns);
	188	value = duty;
	189
	190	if (value == last) {
	191	/* Run the old program */
	192	if (pwm_is_enabled(pwm))
	193	stmpe_24xx_pwm_enable(chip, pwm);
	194
	195	return 0;
	196	} else if (stmpe_pwm->stmpe->partnum == STMPE2403) {
	197	/* STMPE2403 can simply set the right PWM value */
	198	program[0] = LOAD \| value;
	199	program[1] = 0x0000;
	200	} else if (stmpe_pwm->stmpe->partnum == STMPE2401) {
	201	/* STMPE2401 need a complex program */
	202	u16 incdec = 0x0000;
	203
	204	if (last < value)
	205	/* Count up */
	206	incdec = RAMPUP \| (value - last);
	207	else
	208	/* Count down */
209	incdec = RAMPDOWN \| (last - value);
210
211	/* Step to desired value, smoothly */
212	program[0] = PRESCALE_512 \| STEPTIME_1 \| incdec;
213
214	/* Loop eternally to 0x00 */
215	program[1] = BRANCH;
216	}
217
218	dev_dbg(chip->dev,
219	"PWM#%u: value = %02x, last_duty = %02x, program=%04x,%04x,%04x\n",
220	pwm->hwpwm, value, last, program[0], program[1],
221	program[2]);
222	stmpe_pwm->last_duty = value;
223	}
224
225	/*
226	* We can write programs of up to 64 16-bit words into this channel.
227	*/
228	for (i = 0; i < ARRAY_SIZE(program); i++) {
229	u8 value;
230
231	value = (program[i] >> 8) & 0xff;
232
233	ret = stmpe_reg_write(stmpe_pwm->stmpe, offset, value);
234	if (ret) {
235	dev_err(chip->dev, "error writing register %02x: %d\n",
236	offset, ret);
237	return ret;
238	}
239
240	value = program[i] & 0xff;
241
242	ret = stmpe_reg_write(stmpe_pwm->stmpe, offset, value);
243	if (ret) {
244	dev_err(chip->dev, "error writing register %02x: %d\n",
245	offset, ret);
246	return ret;
247	}
248	}
249
250	/* If we were enabled, re-enable this PWM */
251	if (pwm_is_enabled(pwm))
252	stmpe_24xx_pwm_enable(chip, pwm);
253
254	/* Sleep for 200ms so we're sure it will take effect */
255	msleep(200);
256
257	dev_dbg(chip->dev, "programmed PWM#%u, %u bytes\n", pwm->hwpwm, i);
258
259	return 0;
260	}
261
57c95faa UKK	262	static int stmpe_24xx_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	263	const struct pwm_state *state)
	264	{
	265	int err;
	266
	267	if (state->polarity != PWM_POLARITY_NORMAL)
	268	return -EINVAL;
	269
	270	if (!state->enabled) {
	271	if (pwm->state.enabled)
	272	stmpe_24xx_pwm_disable(chip, pwm);
	273
	274	return 0;
	275	}
	276
	277	err = stmpe_24xx_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
	278	if (err)
	279	return err;
	280
	281	if (!pwm->state.enabled)
	282	err = stmpe_24xx_pwm_enable(chip, pwm);
	283
	284	return err;
	285	}
	286
ef1f09ec	287	static const struct pwm_ops stmpe_24xx_pwm_ops = {
57c95faa	288	.apply = stmpe_24xx_pwm_apply,
ef1f09ec LW	289	.owner = THIS_MODULE,
	290	};
	291
	292	static int __init stmpe_pwm_probe(struct platform_device *pdev)
	293	{
	294	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
431c3222	295	struct stmpe_pwm *stmpe_pwm;
ef1f09ec LW	296	int ret;
ef1f09ec LW	297
431c3222 UKK	298	stmpe_pwm = devm_kzalloc(&pdev->dev, sizeof(*stmpe_pwm), GFP_KERNEL);
431c3222 UKK	299	if (!stmpe_pwm)
ef1f09ec LW	300	return -ENOMEM;
ef1f09ec LW	301
431c3222 UKK	302	stmpe_pwm->stmpe = stmpe;
431c3222 UKK	303	stmpe_pwm->chip.dev = &pdev->dev;
ef1f09ec LW	304
ef1f09ec LW	305	if (stmpe->partnum == STMPE2401 \|\| stmpe->partnum == STMPE2403) {
431c3222 UKK	306	stmpe_pwm->chip.ops = &stmpe_24xx_pwm_ops;
431c3222 UKK	307	stmpe_pwm->chip.npwm = 3;
ef1f09ec LW	308	} else {
	309	if (stmpe->partnum == STMPE1601)
	310	dev_err(&pdev->dev, "STMPE1601 not yet supported\n");
	311	else
	312	dev_err(&pdev->dev, "Unknown STMPE PWM\n");
	313
	314	return -ENODEV;
	315	}
	316
	317	ret = stmpe_enable(stmpe, STMPE_BLOCK_PWM);
	318	if (ret)
	319	return ret;
	320
431c3222	321	ret = pwmchip_add(&stmpe_pwm->chip);
ef1f09ec LW	322	if (ret) {
	323	stmpe_disable(stmpe, STMPE_BLOCK_PWM);
	324	return ret;
	325	}
	326
ef1f09ec LW	327	return 0;
	328	}
	329
	330	static struct platform_driver stmpe_pwm_driver = {
	331	.driver = {
	332	.name = "stmpe-pwm",
	333	},
	334	};
	335	builtin_platform_driver_probe(stmpe_pwm_driver, stmpe_pwm_probe);