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, value: pwm_config, reg: base, num_bytes: 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: &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: &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 duty_ns: state->duty_cycle, period_ns: 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(mod_no: TWL6030_MODULE_ID1, val: 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(mod_no: TWL6030_MODULE_ID1, val: &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(mod_no: 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(mod_no: TWL6030_MODULE_ID1, val: &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(mod_no: 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 duty_ns: state->duty_cycle, period_ns: 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(mod_no: TWL6030_MODULE_ID1, val: &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(mod_no: 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(mod_no: TWL6030_MODULE_ID1, val: &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(mod_no: 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(parent: &pdev->dev, npwm, sizeof_priv: 0);
329 if (IS_ERR(ptr: chip))
330 return PTR_ERR(ptr: 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");
359

source code of linux/drivers/pwm/pwm-twl-led.c