pwm-twl-led.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for TWL4030/6030 Pulse Width Modulator used as LED driver
  4 *
  5 * Copyright (C) 2012 Texas Instruments
  6 * Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
  7 *
  8 * This driver is a complete rewrite of the former pwm-twl6030.c authorded by:
  9 * Hemanth V <hemanthv@ti.com>
 10 *
 11 * Reference manual for the twl6030 is available at:
 12 * https://www.ti.com/lit/ds/symlink/twl6030.pdf
 13 *
 14 * Limitations:
 15 * - The twl6030 hardware only supports two period lengths (128 clock ticks and
 16 *   64 clock ticks), the driver only uses 128 ticks
 17 * - The hardware doesn't support ON = 0, so the active part of a period doesn't
 18 *   start at its beginning.
 19 * - The hardware could support inverted polarity (with a similar limitation as
 20 *   for normal: the last clock tick is always inactive).
 21 * - The hardware emits a constant low output when disabled.
 22 * - A request for .duty_cycle = 0 results in an output wave with one active
 23 *   clock tick per period. This should better use the disabled state.
 24 * - The driver only implements setting the relative duty cycle.
 25 * - The driver doesn't implement .get_state().
 26 */
 27
 28#include <linux/module.h>
 29#include <linux/of.h>
 30#include <linux/platform_device.h>
 31#include <linux/pwm.h>
 32#include <linux/mfd/twl.h>
 33#include <linux/slab.h>
 34
 35/*
 36 * This driver handles the PWM driven LED terminals of TWL4030 and TWL6030.
 37 * To generate the signal on TWL4030:
 38 *  - LEDA uses PWMA
 39 *  - LEDB uses PWMB
 40 * TWL6030 has one LED pin with dedicated LEDPWM
 41 */
 42
 43#define TWL4030_LED_MAX		0x7f
 44#define TWL6030_LED_MAX		0xff
 45
 46/* Registers, bits and macro for TWL4030 */
 47#define TWL4030_LEDEN_REG	0x00
 48#define TWL4030_PWMA_REG	0x01
 49
 50#define TWL4030_LEDXON		(1 << 0)
 51#define TWL4030_LEDXPWM		(1 << 4)
 52#define TWL4030_LED_PINS	(TWL4030_LEDXON | TWL4030_LEDXPWM)
 53#define TWL4030_LED_TOGGLE(led, x)	((x) << (led))
 54
 55/* Register, bits and macro for TWL6030 */
 56#define TWL6030_LED_PWM_CTRL1	0xf4
 57#define TWL6030_LED_PWM_CTRL2	0xf5
 58
 59#define TWL6040_LED_MODE_HW	0x00
 60#define TWL6040_LED_MODE_ON	0x01
 61#define TWL6040_LED_MODE_OFF	0x02
 62#define TWL6040_LED_MODE_MASK	0x03
 63
 64static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
 65{
 66	return pwmchip_get_drvdata(chip);
 67}
 68
 69static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
 70			      int duty_ns, int period_ns)
 71{
 72	int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
 73	u8 pwm_config[2] = { 1, 0 };
 74	int base, ret;
 75
 76	/*
 77	 * To configure the duty period:
 78	 * On-cycle is set to 1 (the minimum allowed value)
 79	 * The off time of 0 is not configurable, so the mapping is:
 80	 * 0 -> off cycle = 2,
 81	 * 1 -> off cycle = 2,
 82	 * 2 -> off cycle = 3,
 83	 * 126 - > off cycle 127,
 84	 * 127 - > off cycle 1
 85	 * When on cycle == off cycle the PWM will be always on
 86	 */
 87	if (duty_cycle == 1)
 88		duty_cycle = 2;
 89	else if (duty_cycle > TWL4030_LED_MAX)
 90		duty_cycle = 1;
 91
 92	base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
 93
 94	pwm_config[1] = duty_cycle;
 95
 96	ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
 97	if (ret < 0)
 98		dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
 99
100	return ret;
101}
102
103static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
104{
105	int ret;
106	u8 val;
107
108	ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
109	if (ret < 0) {
110		dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
111		return ret;
112	}
113
114	val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
115
116	ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
117	if (ret < 0)
118		dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
119
120	return ret;
121}
122
123static void twl4030_pwmled_disable(struct pwm_chip *chip,
124				   struct pwm_device *pwm)
125{
126	int ret;
127	u8 val;
128
129	ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
130	if (ret < 0) {
131		dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
132		return;
133	}
134
135	val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
136
137	ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
138	if (ret < 0)
139		dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
140}
141
142static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
143				const struct pwm_state *state)
144{
145	int ret;
146
147	if (state->polarity != PWM_POLARITY_NORMAL)
148		return -EINVAL;
149
150	if (!state->enabled) {
151		if (pwm->state.enabled)
152			twl4030_pwmled_disable(chip, pwm);
153
154		return 0;
155	}
156
157	/*
158	 * We cannot skip calling ->config even if state->period ==
159	 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
160	 * because we might have exited early in the last call to
161	 * pwm_apply_might_sleep because of !state->enabled and so the two values in
162	 * pwm->state might not be configured in hardware.
163	 */
164	ret = twl4030_pwmled_config(chip, pwm,
165				    state->duty_cycle, state->period);
166	if (ret)
167		return ret;
168
169	if (!pwm->state.enabled)
170		ret = twl4030_pwmled_enable(chip, pwm);
171
172	return ret;
173}
174
175
176static const struct pwm_ops twl4030_pwmled_ops = {
177	.apply = twl4030_pwmled_apply,
178};
179
180static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
181			      int duty_ns, int period_ns)
182{
183	int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
184	u8 on_time;
185	int ret;
186
187	on_time = duty_cycle & 0xff;
188
189	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
190			       TWL6030_LED_PWM_CTRL1);
191	if (ret < 0)
192		dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
193
194	return ret;
195}
196
197static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
198{
199	int ret;
200	u8 val;
201
202	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
203	if (ret < 0) {
204		dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
205			pwm->label);
206		return ret;
207	}
208
209	val &= ~TWL6040_LED_MODE_MASK;
210	val |= TWL6040_LED_MODE_ON;
211
212	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
213	if (ret < 0)
214		dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
215
216	return ret;
217}
218
219static void twl6030_pwmled_disable(struct pwm_chip *chip,
220				   struct pwm_device *pwm)
221{
222	int ret;
223	u8 val;
224
225	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
226	if (ret < 0) {
227		dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
228			pwm->label);
229		return;
230	}
231
232	val &= ~TWL6040_LED_MODE_MASK;
233	val |= TWL6040_LED_MODE_OFF;
234
235	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
236	if (ret < 0)
237		dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
238}
239
240static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
241				const struct pwm_state *state)
242{
243	int err;
244
245	if (state->polarity != pwm->state.polarity)
246		return -EINVAL;
247
248	if (!state->enabled) {
249		if (pwm->state.enabled)
250			twl6030_pwmled_disable(chip, pwm);
251
252		return 0;
253	}
254
255	err = twl6030_pwmled_config(chip, pwm,
256				    state->duty_cycle, state->period);
257	if (err)
258		return err;
259
260	if (!pwm->state.enabled)
261		err = twl6030_pwmled_enable(chip, pwm);
262
263	return err;
264}
265
266static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
267{
268	int ret;
269	u8 val;
270
271	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
272	if (ret < 0) {
273		dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
274			pwm->label);
275		return ret;
276	}
277
278	val &= ~TWL6040_LED_MODE_MASK;
279	val |= TWL6040_LED_MODE_OFF;
280
281	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
282	if (ret < 0)
283		dev_err(pwmchip_parent(chip), "%s: Failed to request PWM\n", pwm->label);
284
285	return ret;
286}
287
288static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
289{
290	int ret;
291	u8 val;
292
293	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
294	if (ret < 0) {
295		dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
296			pwm->label);
297		return;
298	}
299
300	val &= ~TWL6040_LED_MODE_MASK;
301	val |= TWL6040_LED_MODE_HW;
302
303	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
304	if (ret < 0)
305		dev_err(pwmchip_parent(chip), "%s: Failed to free PWM\n", pwm->label);
306}
307
308static const struct pwm_ops twl6030_pwmled_ops = {
309	.apply = twl6030_pwmled_apply,
310	.request = twl6030_pwmled_request,
311	.free = twl6030_pwmled_free,
312};
313
314static int twl_pwmled_probe(struct platform_device *pdev)
315{
316	struct pwm_chip *chip;
317	unsigned int npwm;
318	const struct pwm_ops *ops;
319
320	if (twl_class_is_4030()) {
321		ops = &twl4030_pwmled_ops;
322		npwm = 2;
323	} else {
324		ops = &twl6030_pwmled_ops;
325		npwm = 1;
326	}
327
328	chip = devm_pwmchip_alloc(&pdev->dev, npwm, 0);
329	if (IS_ERR(chip))
330		return PTR_ERR(chip);
331
332	chip->ops = ops;
333
334	return devm_pwmchip_add(&pdev->dev, chip);
335}
336
337#ifdef CONFIG_OF
338static const struct of_device_id twl_pwmled_of_match[] = {
339	{ .compatible = "ti,twl4030-pwmled" },
340	{ .compatible = "ti,twl6030-pwmled" },
341	{ },
342};
343MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
344#endif
345
346static struct platform_driver twl_pwmled_driver = {
347	.driver = {
348		.name = "twl-pwmled",
349		.of_match_table = of_match_ptr(twl_pwmled_of_match),
350	},
351	.probe = twl_pwmled_probe,
352};
353module_platform_driver(twl_pwmled_driver);
354
355MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
356MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
357MODULE_ALIAS("platform:twl-pwmled");
358MODULE_LICENSE("GPL");