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