xref: /openbmc/linux/drivers/pwm/pwm-twl-led.c (revision a10c3d5f)
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 
64 struct twl_pwmled_chip {
65 	struct pwm_chip chip;
66 	struct mutex mutex;
67 };
68 
to_twl(struct pwm_chip * chip)69 static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
70 {
71 	return container_of(chip, struct twl_pwmled_chip, chip);
72 }
73 
twl4030_pwmled_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)74 static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
75 			      int duty_ns, int period_ns)
76 {
77 	int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
78 	u8 pwm_config[2] = { 1, 0 };
79 	int base, ret;
80 
81 	/*
82 	 * To configure the duty period:
83 	 * On-cycle is set to 1 (the minimum allowed value)
84 	 * The off time of 0 is not configurable, so the mapping is:
85 	 * 0 -> off cycle = 2,
86 	 * 1 -> off cycle = 2,
87 	 * 2 -> off cycle = 3,
88 	 * 126 - > off cycle 127,
89 	 * 127 - > off cycle 1
90 	 * When on cycle == off cycle the PWM will be always on
91 	 */
92 	if (duty_cycle == 1)
93 		duty_cycle = 2;
94 	else if (duty_cycle > TWL4030_LED_MAX)
95 		duty_cycle = 1;
96 
97 	base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
98 
99 	pwm_config[1] = duty_cycle;
100 
101 	ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
102 	if (ret < 0)
103 		dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
104 
105 	return ret;
106 }
107 
twl4030_pwmled_enable(struct pwm_chip * chip,struct pwm_device * pwm)108 static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
109 {
110 	struct twl_pwmled_chip *twl = to_twl(chip);
111 	int ret;
112 	u8 val;
113 
114 	mutex_lock(&twl->mutex);
115 	ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
116 	if (ret < 0) {
117 		dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
118 		goto out;
119 	}
120 
121 	val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
122 
123 	ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
124 	if (ret < 0)
125 		dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
126 
127 out:
128 	mutex_unlock(&twl->mutex);
129 	return ret;
130 }
131 
twl4030_pwmled_disable(struct pwm_chip * chip,struct pwm_device * pwm)132 static void twl4030_pwmled_disable(struct pwm_chip *chip,
133 				   struct pwm_device *pwm)
134 {
135 	struct twl_pwmled_chip *twl = to_twl(chip);
136 	int ret;
137 	u8 val;
138 
139 	mutex_lock(&twl->mutex);
140 	ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
141 	if (ret < 0) {
142 		dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
143 		goto out;
144 	}
145 
146 	val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
147 
148 	ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
149 	if (ret < 0)
150 		dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
151 
152 out:
153 	mutex_unlock(&twl->mutex);
154 }
155 
twl4030_pwmled_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)156 static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
157 				const struct pwm_state *state)
158 {
159 	int ret;
160 
161 	if (state->polarity != PWM_POLARITY_NORMAL)
162 		return -EINVAL;
163 
164 	if (!state->enabled) {
165 		if (pwm->state.enabled)
166 			twl4030_pwmled_disable(chip, pwm);
167 
168 		return 0;
169 	}
170 
171 	/*
172 	 * We cannot skip calling ->config even if state->period ==
173 	 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
174 	 * because we might have exited early in the last call to
175 	 * pwm_apply_might_sleep because of !state->enabled and so the two values in
176 	 * pwm->state might not be configured in hardware.
177 	 */
178 	ret = twl4030_pwmled_config(pwm->chip, pwm,
179 				    state->duty_cycle, state->period);
180 	if (ret)
181 		return ret;
182 
183 	if (!pwm->state.enabled)
184 		ret = twl4030_pwmled_enable(chip, pwm);
185 
186 	return ret;
187 }
188 
189 
190 static const struct pwm_ops twl4030_pwmled_ops = {
191 	.apply = twl4030_pwmled_apply,
192 	.owner = THIS_MODULE,
193 };
194 
twl6030_pwmled_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)195 static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
196 			      int duty_ns, int period_ns)
197 {
198 	int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
199 	u8 on_time;
200 	int ret;
201 
202 	on_time = duty_cycle & 0xff;
203 
204 	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
205 			       TWL6030_LED_PWM_CTRL1);
206 	if (ret < 0)
207 		dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
208 
209 	return ret;
210 }
211 
twl6030_pwmled_enable(struct pwm_chip * chip,struct pwm_device * pwm)212 static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
213 {
214 	struct twl_pwmled_chip *twl = to_twl(chip);
215 	int ret;
216 	u8 val;
217 
218 	mutex_lock(&twl->mutex);
219 	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
220 	if (ret < 0) {
221 		dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
222 			pwm->label);
223 		goto out;
224 	}
225 
226 	val &= ~TWL6040_LED_MODE_MASK;
227 	val |= TWL6040_LED_MODE_ON;
228 
229 	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
230 	if (ret < 0)
231 		dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
232 
233 out:
234 	mutex_unlock(&twl->mutex);
235 	return ret;
236 }
237 
twl6030_pwmled_disable(struct pwm_chip * chip,struct pwm_device * pwm)238 static void twl6030_pwmled_disable(struct pwm_chip *chip,
239 				   struct pwm_device *pwm)
240 {
241 	struct twl_pwmled_chip *twl = to_twl(chip);
242 	int ret;
243 	u8 val;
244 
245 	mutex_lock(&twl->mutex);
246 	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
247 	if (ret < 0) {
248 		dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
249 			pwm->label);
250 		goto out;
251 	}
252 
253 	val &= ~TWL6040_LED_MODE_MASK;
254 	val |= TWL6040_LED_MODE_OFF;
255 
256 	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
257 	if (ret < 0)
258 		dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
259 
260 out:
261 	mutex_unlock(&twl->mutex);
262 }
263 
twl6030_pwmled_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)264 static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
265 				const struct pwm_state *state)
266 {
267 	int err;
268 
269 	if (state->polarity != pwm->state.polarity)
270 		return -EINVAL;
271 
272 	if (!state->enabled) {
273 		if (pwm->state.enabled)
274 			twl6030_pwmled_disable(chip, pwm);
275 
276 		return 0;
277 	}
278 
279 	err = twl6030_pwmled_config(pwm->chip, pwm,
280 				    state->duty_cycle, state->period);
281 	if (err)
282 		return err;
283 
284 	if (!pwm->state.enabled)
285 		err = twl6030_pwmled_enable(chip, pwm);
286 
287 	return err;
288 }
289 
twl6030_pwmled_request(struct pwm_chip * chip,struct pwm_device * pwm)290 static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
291 {
292 	struct twl_pwmled_chip *twl = to_twl(chip);
293 	int ret;
294 	u8 val;
295 
296 	mutex_lock(&twl->mutex);
297 	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
298 	if (ret < 0) {
299 		dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
300 			pwm->label);
301 		goto out;
302 	}
303 
304 	val &= ~TWL6040_LED_MODE_MASK;
305 	val |= TWL6040_LED_MODE_OFF;
306 
307 	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
308 	if (ret < 0)
309 		dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
310 
311 out:
312 	mutex_unlock(&twl->mutex);
313 	return ret;
314 }
315 
twl6030_pwmled_free(struct pwm_chip * chip,struct pwm_device * pwm)316 static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
317 {
318 	struct twl_pwmled_chip *twl = to_twl(chip);
319 	int ret;
320 	u8 val;
321 
322 	mutex_lock(&twl->mutex);
323 	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
324 	if (ret < 0) {
325 		dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
326 			pwm->label);
327 		goto out;
328 	}
329 
330 	val &= ~TWL6040_LED_MODE_MASK;
331 	val |= TWL6040_LED_MODE_HW;
332 
333 	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
334 	if (ret < 0)
335 		dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
336 
337 out:
338 	mutex_unlock(&twl->mutex);
339 }
340 
341 static const struct pwm_ops twl6030_pwmled_ops = {
342 	.apply = twl6030_pwmled_apply,
343 	.request = twl6030_pwmled_request,
344 	.free = twl6030_pwmled_free,
345 	.owner = THIS_MODULE,
346 };
347 
twl_pwmled_probe(struct platform_device * pdev)348 static int twl_pwmled_probe(struct platform_device *pdev)
349 {
350 	struct twl_pwmled_chip *twl;
351 
352 	twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
353 	if (!twl)
354 		return -ENOMEM;
355 
356 	if (twl_class_is_4030()) {
357 		twl->chip.ops = &twl4030_pwmled_ops;
358 		twl->chip.npwm = 2;
359 	} else {
360 		twl->chip.ops = &twl6030_pwmled_ops;
361 		twl->chip.npwm = 1;
362 	}
363 
364 	twl->chip.dev = &pdev->dev;
365 
366 	mutex_init(&twl->mutex);
367 
368 	return devm_pwmchip_add(&pdev->dev, &twl->chip);
369 }
370 
371 #ifdef CONFIG_OF
372 static const struct of_device_id twl_pwmled_of_match[] = {
373 	{ .compatible = "ti,twl4030-pwmled" },
374 	{ .compatible = "ti,twl6030-pwmled" },
375 	{ },
376 };
377 MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
378 #endif
379 
380 static struct platform_driver twl_pwmled_driver = {
381 	.driver = {
382 		.name = "twl-pwmled",
383 		.of_match_table = of_match_ptr(twl_pwmled_of_match),
384 	},
385 	.probe = twl_pwmled_probe,
386 };
387 module_platform_driver(twl_pwmled_driver);
388 
389 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
390 MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
391 MODULE_ALIAS("platform:twl-pwmled");
392 MODULE_LICENSE("GPL");
393