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 mutex mutex;
66 };
67
to_twl(struct pwm_chip * chip)68 static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
69 {
70 return pwmchip_get_drvdata(chip);
71 }
72
twl4030_pwmled_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)73 static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
74 int duty_ns, int period_ns)
75 {
76 int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
77 u8 pwm_config[2] = { 1, 0 };
78 int base, ret;
79
80 /*
81 * To configure the duty period:
82 * On-cycle is set to 1 (the minimum allowed value)
83 * The off time of 0 is not configurable, so the mapping is:
84 * 0 -> off cycle = 2,
85 * 1 -> off cycle = 2,
86 * 2 -> off cycle = 3,
87 * 126 - > off cycle 127,
88 * 127 - > off cycle 1
89 * When on cycle == off cycle the PWM will be always on
90 */
91 if (duty_cycle == 1)
92 duty_cycle = 2;
93 else if (duty_cycle > TWL4030_LED_MAX)
94 duty_cycle = 1;
95
96 base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
97
98 pwm_config[1] = duty_cycle;
99
100 ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
101 if (ret < 0)
102 dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
103
104 return ret;
105 }
106
twl4030_pwmled_enable(struct pwm_chip * chip,struct pwm_device * pwm)107 static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
108 {
109 struct twl_pwmled_chip *twl = to_twl(chip);
110 int ret;
111 u8 val;
112
113 mutex_lock(&twl->mutex);
114 ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
115 if (ret < 0) {
116 dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
117 goto out;
118 }
119
120 val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
121
122 ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
123 if (ret < 0)
124 dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
125
126 out:
127 mutex_unlock(&twl->mutex);
128 return ret;
129 }
130
twl4030_pwmled_disable(struct pwm_chip * chip,struct pwm_device * pwm)131 static void twl4030_pwmled_disable(struct pwm_chip *chip,
132 struct pwm_device *pwm)
133 {
134 struct twl_pwmled_chip *twl = to_twl(chip);
135 int ret;
136 u8 val;
137
138 mutex_lock(&twl->mutex);
139 ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
140 if (ret < 0) {
141 dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
142 goto out;
143 }
144
145 val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
146
147 ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
148 if (ret < 0)
149 dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
150
151 out:
152 mutex_unlock(&twl->mutex);
153 }
154
twl4030_pwmled_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)155 static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
156 const struct pwm_state *state)
157 {
158 int ret;
159
160 if (state->polarity != PWM_POLARITY_NORMAL)
161 return -EINVAL;
162
163 if (!state->enabled) {
164 if (pwm->state.enabled)
165 twl4030_pwmled_disable(chip, pwm);
166
167 return 0;
168 }
169
170 /*
171 * We cannot skip calling ->config even if state->period ==
172 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
173 * because we might have exited early in the last call to
174 * pwm_apply_might_sleep because of !state->enabled and so the two values in
175 * pwm->state might not be configured in hardware.
176 */
177 ret = twl4030_pwmled_config(chip, pwm,
178 state->duty_cycle, state->period);
179 if (ret)
180 return ret;
181
182 if (!pwm->state.enabled)
183 ret = twl4030_pwmled_enable(chip, pwm);
184
185 return ret;
186 }
187
188
189 static const struct pwm_ops twl4030_pwmled_ops = {
190 .apply = twl4030_pwmled_apply,
191 };
192
twl6030_pwmled_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)193 static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
194 int duty_ns, int period_ns)
195 {
196 int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
197 u8 on_time;
198 int ret;
199
200 on_time = duty_cycle & 0xff;
201
202 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
203 TWL6030_LED_PWM_CTRL1);
204 if (ret < 0)
205 dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
206
207 return ret;
208 }
209
twl6030_pwmled_enable(struct pwm_chip * chip,struct pwm_device * pwm)210 static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
211 {
212 struct twl_pwmled_chip *twl = to_twl(chip);
213 int ret;
214 u8 val;
215
216 mutex_lock(&twl->mutex);
217 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
218 if (ret < 0) {
219 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
220 pwm->label);
221 goto out;
222 }
223
224 val &= ~TWL6040_LED_MODE_MASK;
225 val |= TWL6040_LED_MODE_ON;
226
227 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
228 if (ret < 0)
229 dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
230
231 out:
232 mutex_unlock(&twl->mutex);
233 return ret;
234 }
235
twl6030_pwmled_disable(struct pwm_chip * chip,struct pwm_device * pwm)236 static void twl6030_pwmled_disable(struct pwm_chip *chip,
237 struct pwm_device *pwm)
238 {
239 struct twl_pwmled_chip *twl = to_twl(chip);
240 int ret;
241 u8 val;
242
243 mutex_lock(&twl->mutex);
244 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
245 if (ret < 0) {
246 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
247 pwm->label);
248 goto out;
249 }
250
251 val &= ~TWL6040_LED_MODE_MASK;
252 val |= TWL6040_LED_MODE_OFF;
253
254 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
255 if (ret < 0)
256 dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
257
258 out:
259 mutex_unlock(&twl->mutex);
260 }
261
twl6030_pwmled_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)262 static int twl6030_pwmled_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->state.polarity)
268 return -EINVAL;
269
270 if (!state->enabled) {
271 if (pwm->state.enabled)
272 twl6030_pwmled_disable(chip, pwm);
273
274 return 0;
275 }
276
277 err = twl6030_pwmled_config(chip, pwm,
278 state->duty_cycle, state->period);
279 if (err)
280 return err;
281
282 if (!pwm->state.enabled)
283 err = twl6030_pwmled_enable(chip, pwm);
284
285 return err;
286 }
287
twl6030_pwmled_request(struct pwm_chip * chip,struct pwm_device * pwm)288 static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
289 {
290 struct twl_pwmled_chip *twl = to_twl(chip);
291 int ret;
292 u8 val;
293
294 mutex_lock(&twl->mutex);
295 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
296 if (ret < 0) {
297 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
298 pwm->label);
299 goto out;
300 }
301
302 val &= ~TWL6040_LED_MODE_MASK;
303 val |= TWL6040_LED_MODE_OFF;
304
305 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
306 if (ret < 0)
307 dev_err(pwmchip_parent(chip), "%s: Failed to request PWM\n", pwm->label);
308
309 out:
310 mutex_unlock(&twl->mutex);
311 return ret;
312 }
313
twl6030_pwmled_free(struct pwm_chip * chip,struct pwm_device * pwm)314 static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
315 {
316 struct twl_pwmled_chip *twl = to_twl(chip);
317 int ret;
318 u8 val;
319
320 mutex_lock(&twl->mutex);
321 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
322 if (ret < 0) {
323 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
324 pwm->label);
325 goto out;
326 }
327
328 val &= ~TWL6040_LED_MODE_MASK;
329 val |= TWL6040_LED_MODE_HW;
330
331 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
332 if (ret < 0)
333 dev_err(pwmchip_parent(chip), "%s: Failed to free PWM\n", pwm->label);
334
335 out:
336 mutex_unlock(&twl->mutex);
337 }
338
339 static const struct pwm_ops twl6030_pwmled_ops = {
340 .apply = twl6030_pwmled_apply,
341 .request = twl6030_pwmled_request,
342 .free = twl6030_pwmled_free,
343 };
344
twl_pwmled_probe(struct platform_device * pdev)345 static int twl_pwmled_probe(struct platform_device *pdev)
346 {
347 struct pwm_chip *chip;
348 struct twl_pwmled_chip *twl;
349 unsigned int npwm;
350 const struct pwm_ops *ops;
351
352 if (twl_class_is_4030()) {
353 ops = &twl4030_pwmled_ops;
354 npwm = 2;
355 } else {
356 ops = &twl6030_pwmled_ops;
357 npwm = 1;
358 }
359
360 chip = devm_pwmchip_alloc(&pdev->dev, npwm, sizeof(*twl));
361 if (IS_ERR(chip))
362 return PTR_ERR(chip);
363 twl = to_twl(chip);
364
365 chip->ops = ops;
366
367 mutex_init(&twl->mutex);
368
369 return devm_pwmchip_add(&pdev->dev, chip);
370 }
371
372 #ifdef CONFIG_OF
373 static const struct of_device_id twl_pwmled_of_match[] = {
374 { .compatible = "ti,twl4030-pwmled" },
375 { .compatible = "ti,twl6030-pwmled" },
376 { },
377 };
378 MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
379 #endif
380
381 static struct platform_driver twl_pwmled_driver = {
382 .driver = {
383 .name = "twl-pwmled",
384 .of_match_table = of_match_ptr(twl_pwmled_of_match),
385 },
386 .probe = twl_pwmled_probe,
387 };
388 module_platform_driver(twl_pwmled_driver);
389
390 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
391 MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
392 MODULE_ALIAS("platform:twl-pwmled");
393 MODULE_LICENSE("GPL");
394