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1 | /* |
2 | * TI/National Semiconductor LP3943 PWM driver | |
3 | * | |
4 | * Copyright 2013 Texas Instruments | |
5 | * | |
6 | * Author: Milo Kim <milo.kim@ti.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; version 2. | |
11 | */ | |
12 | ||
13 | #include <linux/err.h> | |
14 | #include <linux/i2c.h> | |
15 | #include <linux/mfd/lp3943.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/pwm.h> | |
19 | #include <linux/slab.h> | |
20 | ||
21 | #define LP3943_MAX_DUTY 255 | |
22 | #define LP3943_MIN_PERIOD 6250 | |
23 | #define LP3943_MAX_PERIOD 1600000 | |
24 | ||
25 | struct lp3943_pwm { | |
26 | struct pwm_chip chip; | |
27 | struct lp3943 *lp3943; | |
28 | struct lp3943_platform_data *pdata; | |
29 | }; | |
30 | ||
31 | static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip) | |
32 | { | |
33 | return container_of(_chip, struct lp3943_pwm, chip); | |
34 | } | |
35 | ||
36 | static struct lp3943_pwm_map * | |
37 | lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm) | |
38 | { | |
39 | struct lp3943_platform_data *pdata = lp3943_pwm->pdata; | |
40 | struct lp3943 *lp3943 = lp3943_pwm->lp3943; | |
41 | struct lp3943_pwm_map *pwm_map; | |
42 | int i, offset; | |
43 | ||
44 | pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL); | |
45 | if (!pwm_map) | |
46 | return ERR_PTR(-ENOMEM); | |
47 | ||
48 | pwm_map->output = pdata->pwms[hwpwm]->output; | |
49 | pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs; | |
50 | ||
51 | for (i = 0; i < pwm_map->num_outputs; i++) { | |
52 | offset = pwm_map->output[i]; | |
53 | ||
54 | /* Return an error if the pin is already assigned */ | |
0b7d25c3 CE |
55 | if (test_and_set_bit(offset, &lp3943->pin_used)) { |
56 | kfree(pwm_map); | |
af66b3c0 | 57 | return ERR_PTR(-EBUSY); |
0b7d25c3 | 58 | } |
af66b3c0 MK |
59 | } |
60 | ||
61 | return pwm_map; | |
62 | } | |
63 | ||
64 | static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) | |
65 | { | |
66 | struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); | |
67 | struct lp3943_pwm_map *pwm_map; | |
68 | ||
69 | pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm); | |
70 | if (IS_ERR(pwm_map)) | |
71 | return PTR_ERR(pwm_map); | |
72 | ||
73 | return pwm_set_chip_data(pwm, pwm_map); | |
74 | } | |
75 | ||
76 | static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm, | |
77 | struct lp3943_pwm_map *pwm_map) | |
78 | { | |
79 | struct lp3943 *lp3943 = lp3943_pwm->lp3943; | |
80 | int i, offset; | |
81 | ||
82 | for (i = 0; i < pwm_map->num_outputs; i++) { | |
83 | offset = pwm_map->output[i]; | |
84 | clear_bit(offset, &lp3943->pin_used); | |
85 | } | |
86 | ||
87 | kfree(pwm_map); | |
88 | } | |
89 | ||
90 | static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) | |
91 | { | |
92 | struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); | |
93 | struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); | |
94 | ||
95 | lp3943_pwm_free_map(lp3943_pwm, pwm_map); | |
96 | } | |
97 | ||
98 | static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, | |
99 | int duty_ns, int period_ns) | |
100 | { | |
101 | struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); | |
102 | struct lp3943 *lp3943 = lp3943_pwm->lp3943; | |
103 | u8 val, reg_duty, reg_prescale; | |
104 | int err; | |
105 | ||
106 | /* | |
107 | * How to configure the LP3943 PWMs | |
108 | * | |
109 | * 1) Period = 6250 ~ 1600000 | |
110 | * 2) Prescale = period / 6250 -1 | |
111 | * 3) Duty = input duty | |
112 | * | |
113 | * Prescale and duty are register values | |
114 | */ | |
115 | ||
116 | if (pwm->hwpwm == 0) { | |
117 | reg_prescale = LP3943_REG_PRESCALE0; | |
118 | reg_duty = LP3943_REG_PWM0; | |
119 | } else { | |
120 | reg_prescale = LP3943_REG_PRESCALE1; | |
121 | reg_duty = LP3943_REG_PWM1; | |
122 | } | |
123 | ||
124 | period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD); | |
125 | val = (u8)(period_ns / LP3943_MIN_PERIOD - 1); | |
126 | ||
127 | err = lp3943_write_byte(lp3943, reg_prescale, val); | |
128 | if (err) | |
129 | return err; | |
130 | ||
131 | val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns); | |
132 | ||
133 | return lp3943_write_byte(lp3943, reg_duty, val); | |
134 | } | |
135 | ||
136 | static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm, | |
137 | struct lp3943_pwm_map *pwm_map, | |
138 | u8 val) | |
139 | { | |
140 | struct lp3943 *lp3943 = lp3943_pwm->lp3943; | |
141 | const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; | |
142 | int i, index, err; | |
143 | ||
144 | for (i = 0; i < pwm_map->num_outputs; i++) { | |
145 | index = pwm_map->output[i]; | |
146 | err = lp3943_update_bits(lp3943, mux[index].reg, | |
147 | mux[index].mask, | |
148 | val << mux[index].shift); | |
149 | if (err) | |
150 | return err; | |
151 | } | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) | |
157 | { | |
158 | struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); | |
159 | struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); | |
160 | u8 val; | |
161 | ||
162 | if (pwm->hwpwm == 0) | |
163 | val = LP3943_DIM_PWM0; | |
164 | else | |
165 | val = LP3943_DIM_PWM1; | |
166 | ||
167 | /* | |
168 | * Each PWM generator is set to control any of outputs of LP3943. | |
169 | * To enable/disable the PWM, these output pins should be configured. | |
170 | */ | |
171 | ||
172 | return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val); | |
173 | } | |
174 | ||
175 | static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) | |
176 | { | |
177 | struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); | |
178 | struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); | |
179 | ||
180 | /* | |
181 | * LP3943 outputs are open-drain, so the pin should be configured | |
182 | * when the PWM is disabled. | |
183 | */ | |
184 | ||
185 | lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH); | |
186 | } | |
187 | ||
188 | static const struct pwm_ops lp3943_pwm_ops = { | |
189 | .request = lp3943_pwm_request, | |
190 | .free = lp3943_pwm_free, | |
191 | .config = lp3943_pwm_config, | |
192 | .enable = lp3943_pwm_enable, | |
193 | .disable = lp3943_pwm_disable, | |
194 | .owner = THIS_MODULE, | |
195 | }; | |
196 | ||
197 | static int lp3943_pwm_parse_dt(struct device *dev, | |
198 | struct lp3943_pwm *lp3943_pwm) | |
199 | { | |
200 | static const char * const name[] = { "ti,pwm0", "ti,pwm1", }; | |
201 | struct device_node *node = dev->of_node; | |
202 | struct lp3943_platform_data *pdata; | |
203 | struct lp3943_pwm_map *pwm_map; | |
204 | enum lp3943_pwm_output *output; | |
205 | int i, err, proplen, count = 0; | |
206 | u32 num_outputs; | |
207 | ||
208 | if (!node) | |
209 | return -EINVAL; | |
210 | ||
211 | pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); | |
212 | if (!pdata) | |
213 | return -ENOMEM; | |
214 | ||
215 | /* | |
216 | * Read the output map configuration from the device tree. | |
217 | * Each of the two PWM generators can drive zero or more outputs. | |
218 | */ | |
219 | ||
220 | for (i = 0; i < LP3943_NUM_PWMS; i++) { | |
221 | if (!of_get_property(node, name[i], &proplen)) | |
222 | continue; | |
223 | ||
224 | num_outputs = proplen / sizeof(u32); | |
225 | if (num_outputs == 0) | |
226 | continue; | |
227 | ||
228 | output = devm_kzalloc(dev, sizeof(*output) * num_outputs, | |
229 | GFP_KERNEL); | |
230 | if (!output) | |
231 | return -ENOMEM; | |
232 | ||
233 | err = of_property_read_u32_array(node, name[i], output, | |
234 | num_outputs); | |
235 | if (err) | |
236 | return err; | |
237 | ||
238 | pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL); | |
239 | if (!pwm_map) | |
240 | return -ENOMEM; | |
241 | ||
242 | pwm_map->output = output; | |
243 | pwm_map->num_outputs = num_outputs; | |
244 | pdata->pwms[i] = pwm_map; | |
245 | ||
246 | count++; | |
247 | } | |
248 | ||
249 | if (count == 0) | |
250 | return -ENODATA; | |
251 | ||
252 | lp3943_pwm->pdata = pdata; | |
253 | return 0; | |
254 | } | |
255 | ||
256 | static int lp3943_pwm_probe(struct platform_device *pdev) | |
257 | { | |
258 | struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); | |
259 | struct lp3943_pwm *lp3943_pwm; | |
260 | int ret; | |
261 | ||
262 | lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL); | |
263 | if (!lp3943_pwm) | |
264 | return -ENOMEM; | |
265 | ||
266 | lp3943_pwm->pdata = lp3943->pdata; | |
267 | if (!lp3943_pwm->pdata) { | |
268 | if (IS_ENABLED(CONFIG_OF)) | |
269 | ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm); | |
270 | else | |
271 | ret = -ENODEV; | |
272 | ||
273 | if (ret) | |
274 | return ret; | |
275 | } | |
276 | ||
277 | lp3943_pwm->lp3943 = lp3943; | |
278 | lp3943_pwm->chip.dev = &pdev->dev; | |
279 | lp3943_pwm->chip.ops = &lp3943_pwm_ops; | |
280 | lp3943_pwm->chip.npwm = LP3943_NUM_PWMS; | |
00afb429 | 281 | lp3943_pwm->chip.can_sleep = true; |
af66b3c0 MK |
282 | |
283 | platform_set_drvdata(pdev, lp3943_pwm); | |
284 | ||
285 | return pwmchip_add(&lp3943_pwm->chip); | |
286 | } | |
287 | ||
288 | static int lp3943_pwm_remove(struct platform_device *pdev) | |
289 | { | |
290 | struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev); | |
291 | ||
292 | return pwmchip_remove(&lp3943_pwm->chip); | |
293 | } | |
294 | ||
295 | #ifdef CONFIG_OF | |
296 | static const struct of_device_id lp3943_pwm_of_match[] = { | |
297 | { .compatible = "ti,lp3943-pwm", }, | |
298 | { } | |
299 | }; | |
300 | MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match); | |
301 | #endif | |
302 | ||
303 | static struct platform_driver lp3943_pwm_driver = { | |
304 | .probe = lp3943_pwm_probe, | |
305 | .remove = lp3943_pwm_remove, | |
306 | .driver = { | |
307 | .name = "lp3943-pwm", | |
af66b3c0 MK |
308 | .of_match_table = of_match_ptr(lp3943_pwm_of_match), |
309 | }, | |
310 | }; | |
311 | module_platform_driver(lp3943_pwm_driver); | |
312 | ||
313 | MODULE_DESCRIPTION("LP3943 PWM driver"); | |
314 | MODULE_ALIAS("platform:lp3943-pwm"); | |
315 | MODULE_AUTHOR("Milo Kim"); | |
316 | MODULE_LICENSE("GPL"); |