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
to_lp3943_pwm(struct pwm_chip * _chip)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 *
lp3943_pwm_request_map(struct lp3943_pwm * lp3943_pwm,int hwpwm)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 kfree(pwm_map);
57 return ERR_PTR(-EBUSY);
58 }
59 }
60
61 return pwm_map;
62 }
63
lp3943_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)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
lp3943_pwm_free_map(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map)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
lp3943_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)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
lp3943_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)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 duty_ns = min(duty_ns, period_ns);
132 val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
133
134 return lp3943_write_byte(lp3943, reg_duty, val);
135 }
136
lp3943_pwm_set_mode(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map,u8 val)137 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
138 struct lp3943_pwm_map *pwm_map,
139 u8 val)
140 {
141 struct lp3943 *lp3943 = lp3943_pwm->lp3943;
142 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
143 int i, index, err;
144
145 for (i = 0; i < pwm_map->num_outputs; i++) {
146 index = pwm_map->output[i];
147 err = lp3943_update_bits(lp3943, mux[index].reg,
148 mux[index].mask,
149 val << mux[index].shift);
150 if (err)
151 return err;
152 }
153
154 return 0;
155 }
156
lp3943_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)157 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
158 {
159 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
160 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
161 u8 val;
162
163 if (pwm->hwpwm == 0)
164 val = LP3943_DIM_PWM0;
165 else
166 val = LP3943_DIM_PWM1;
167
168 /*
169 * Each PWM generator is set to control any of outputs of LP3943.
170 * To enable/disable the PWM, these output pins should be configured.
171 */
172
173 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
174 }
175
lp3943_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)176 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
177 {
178 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
179 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
180
181 /*
182 * LP3943 outputs are open-drain, so the pin should be configured
183 * when the PWM is disabled.
184 */
185
186 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
187 }
188
189 static const struct pwm_ops lp3943_pwm_ops = {
190 .request = lp3943_pwm_request,
191 .free = lp3943_pwm_free,
192 .config = lp3943_pwm_config,
193 .enable = lp3943_pwm_enable,
194 .disable = lp3943_pwm_disable,
195 .owner = THIS_MODULE,
196 };
197
lp3943_pwm_parse_dt(struct device * dev,struct lp3943_pwm * lp3943_pwm)198 static int lp3943_pwm_parse_dt(struct device *dev,
199 struct lp3943_pwm *lp3943_pwm)
200 {
201 static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
202 struct device_node *node = dev->of_node;
203 struct lp3943_platform_data *pdata;
204 struct lp3943_pwm_map *pwm_map;
205 enum lp3943_pwm_output *output;
206 int i, err, proplen, count = 0;
207 u32 num_outputs;
208
209 if (!node)
210 return -EINVAL;
211
212 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
213 if (!pdata)
214 return -ENOMEM;
215
216 /*
217 * Read the output map configuration from the device tree.
218 * Each of the two PWM generators can drive zero or more outputs.
219 */
220
221 for (i = 0; i < LP3943_NUM_PWMS; i++) {
222 if (!of_get_property(node, name[i], &proplen))
223 continue;
224
225 num_outputs = proplen / sizeof(u32);
226 if (num_outputs == 0)
227 continue;
228
229 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
230 GFP_KERNEL);
231 if (!output)
232 return -ENOMEM;
233
234 err = of_property_read_u32_array(node, name[i], output,
235 num_outputs);
236 if (err)
237 return err;
238
239 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
240 if (!pwm_map)
241 return -ENOMEM;
242
243 pwm_map->output = output;
244 pwm_map->num_outputs = num_outputs;
245 pdata->pwms[i] = pwm_map;
246
247 count++;
248 }
249
250 if (count == 0)
251 return -ENODATA;
252
253 lp3943_pwm->pdata = pdata;
254 return 0;
255 }
256
lp3943_pwm_probe(struct platform_device * pdev)257 static int lp3943_pwm_probe(struct platform_device *pdev)
258 {
259 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
260 struct lp3943_pwm *lp3943_pwm;
261 int ret;
262
263 lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
264 if (!lp3943_pwm)
265 return -ENOMEM;
266
267 lp3943_pwm->pdata = lp3943->pdata;
268 if (!lp3943_pwm->pdata) {
269 if (IS_ENABLED(CONFIG_OF))
270 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
271 else
272 ret = -ENODEV;
273
274 if (ret)
275 return ret;
276 }
277
278 lp3943_pwm->lp3943 = lp3943;
279 lp3943_pwm->chip.dev = &pdev->dev;
280 lp3943_pwm->chip.ops = &lp3943_pwm_ops;
281 lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
282 lp3943_pwm->chip.base = -1;
283
284 platform_set_drvdata(pdev, lp3943_pwm);
285
286 return pwmchip_add(&lp3943_pwm->chip);
287 }
288
lp3943_pwm_remove(struct platform_device * pdev)289 static int lp3943_pwm_remove(struct platform_device *pdev)
290 {
291 struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
292
293 return pwmchip_remove(&lp3943_pwm->chip);
294 }
295
296 #ifdef CONFIG_OF
297 static const struct of_device_id lp3943_pwm_of_match[] = {
298 { .compatible = "ti,lp3943-pwm", },
299 { }
300 };
301 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
302 #endif
303
304 static struct platform_driver lp3943_pwm_driver = {
305 .probe = lp3943_pwm_probe,
306 .remove = lp3943_pwm_remove,
307 .driver = {
308 .name = "lp3943-pwm",
309 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
310 },
311 };
312 module_platform_driver(lp3943_pwm_driver);
313
314 MODULE_DESCRIPTION("LP3943 PWM driver");
315 MODULE_ALIAS("platform:lp3943-pwm");
316 MODULE_AUTHOR("Milo Kim");
317 MODULE_LICENSE("GPL");
318