1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * TI/National Semiconductor LP3943 PWM driver
4 *
5 * Copyright 2013 Texas Instruments
6 *
7 * Author: Milo Kim <milo.kim@ti.com>
8 */
9
10 #include <linux/err.h>
11 #include <linux/mfd/lp3943.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/pwm.h>
16 #include <linux/slab.h>
17
18 #define LP3943_MAX_DUTY 255
19 #define LP3943_MIN_PERIOD 6250
20 #define LP3943_MAX_PERIOD 1600000
21
22 struct lp3943_pwm {
23 struct pwm_chip chip;
24 struct lp3943 *lp3943;
25 struct lp3943_platform_data *pdata;
26 };
27
to_lp3943_pwm(struct pwm_chip * chip)28 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip)
29 {
30 return container_of(chip, struct lp3943_pwm, chip);
31 }
32
33 static struct lp3943_pwm_map *
lp3943_pwm_request_map(struct lp3943_pwm * lp3943_pwm,int hwpwm)34 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
35 {
36 struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
37 struct lp3943 *lp3943 = lp3943_pwm->lp3943;
38 struct lp3943_pwm_map *pwm_map;
39 int i, offset;
40
41 pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
42 if (!pwm_map)
43 return ERR_PTR(-ENOMEM);
44
45 pwm_map->output = pdata->pwms[hwpwm]->output;
46 pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
47
48 for (i = 0; i < pwm_map->num_outputs; i++) {
49 offset = pwm_map->output[i];
50
51 /* Return an error if the pin is already assigned */
52 if (test_and_set_bit(offset, &lp3943->pin_used)) {
53 kfree(pwm_map);
54 return ERR_PTR(-EBUSY);
55 }
56 }
57
58 return pwm_map;
59 }
60
lp3943_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)61 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
62 {
63 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
64 struct lp3943_pwm_map *pwm_map;
65
66 pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
67 if (IS_ERR(pwm_map))
68 return PTR_ERR(pwm_map);
69
70 return pwm_set_chip_data(pwm, pwm_map);
71 }
72
lp3943_pwm_free_map(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map)73 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
74 struct lp3943_pwm_map *pwm_map)
75 {
76 struct lp3943 *lp3943 = lp3943_pwm->lp3943;
77 int i, offset;
78
79 for (i = 0; i < pwm_map->num_outputs; i++) {
80 offset = pwm_map->output[i];
81 clear_bit(offset, &lp3943->pin_used);
82 }
83
84 kfree(pwm_map);
85 }
86
lp3943_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)87 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
88 {
89 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
90 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
91
92 lp3943_pwm_free_map(lp3943_pwm, pwm_map);
93 }
94
lp3943_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,u64 duty_ns,u64 period_ns)95 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
96 u64 duty_ns, u64 period_ns)
97 {
98 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
99 struct lp3943 *lp3943 = lp3943_pwm->lp3943;
100 u8 val, reg_duty, reg_prescale;
101 int err;
102
103 /*
104 * How to configure the LP3943 PWMs
105 *
106 * 1) Period = 6250 ~ 1600000
107 * 2) Prescale = period / 6250 -1
108 * 3) Duty = input duty
109 *
110 * Prescale and duty are register values
111 */
112
113 if (pwm->hwpwm == 0) {
114 reg_prescale = LP3943_REG_PRESCALE0;
115 reg_duty = LP3943_REG_PWM0;
116 } else {
117 reg_prescale = LP3943_REG_PRESCALE1;
118 reg_duty = LP3943_REG_PWM1;
119 }
120
121 /*
122 * Note that after this clamping, period_ns fits into an int. This is
123 * helpful because we can resort to integer division below instead of
124 * the (more expensive) 64 bit division.
125 */
126 period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD);
127 val = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1);
128
129 err = lp3943_write_byte(lp3943, reg_prescale, val);
130 if (err)
131 return err;
132
133 duty_ns = min(duty_ns, period_ns);
134 val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns);
135
136 return lp3943_write_byte(lp3943, reg_duty, val);
137 }
138
lp3943_pwm_set_mode(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map,u8 val)139 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
140 struct lp3943_pwm_map *pwm_map,
141 u8 val)
142 {
143 struct lp3943 *lp3943 = lp3943_pwm->lp3943;
144 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
145 int i, index, err;
146
147 for (i = 0; i < pwm_map->num_outputs; i++) {
148 index = pwm_map->output[i];
149 err = lp3943_update_bits(lp3943, mux[index].reg,
150 mux[index].mask,
151 val << mux[index].shift);
152 if (err)
153 return err;
154 }
155
156 return 0;
157 }
158
lp3943_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)159 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
160 {
161 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
162 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
163 u8 val;
164
165 if (pwm->hwpwm == 0)
166 val = LP3943_DIM_PWM0;
167 else
168 val = LP3943_DIM_PWM1;
169
170 /*
171 * Each PWM generator is set to control any of outputs of LP3943.
172 * To enable/disable the PWM, these output pins should be configured.
173 */
174
175 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
176 }
177
lp3943_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)178 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
179 {
180 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
181 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
182
183 /*
184 * LP3943 outputs are open-drain, so the pin should be configured
185 * when the PWM is disabled.
186 */
187
188 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
189 }
190
lp3943_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)191 static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
192 const struct pwm_state *state)
193 {
194 int err;
195
196 if (state->polarity != PWM_POLARITY_NORMAL)
197 return -EINVAL;
198
199 if (!state->enabled) {
200 if (pwm->state.enabled)
201 lp3943_pwm_disable(chip, pwm);
202 return 0;
203 }
204
205 err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period);
206 if (err)
207 return err;
208
209 if (!pwm->state.enabled)
210 err = lp3943_pwm_enable(chip, pwm);
211
212 return err;
213 }
214
215 static const struct pwm_ops lp3943_pwm_ops = {
216 .request = lp3943_pwm_request,
217 .free = lp3943_pwm_free,
218 .apply = lp3943_pwm_apply,
219 .owner = THIS_MODULE,
220 };
221
lp3943_pwm_parse_dt(struct device * dev,struct lp3943_pwm * lp3943_pwm)222 static int lp3943_pwm_parse_dt(struct device *dev,
223 struct lp3943_pwm *lp3943_pwm)
224 {
225 static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
226 struct device_node *node = dev->of_node;
227 struct lp3943_platform_data *pdata;
228 struct lp3943_pwm_map *pwm_map;
229 enum lp3943_pwm_output *output;
230 int i, err, proplen, count = 0;
231 u32 num_outputs;
232
233 if (!node)
234 return -EINVAL;
235
236 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
237 if (!pdata)
238 return -ENOMEM;
239
240 /*
241 * Read the output map configuration from the device tree.
242 * Each of the two PWM generators can drive zero or more outputs.
243 */
244
245 for (i = 0; i < LP3943_NUM_PWMS; i++) {
246 if (!of_get_property(node, name[i], &proplen))
247 continue;
248
249 num_outputs = proplen / sizeof(u32);
250 if (num_outputs == 0)
251 continue;
252
253 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
254 GFP_KERNEL);
255 if (!output)
256 return -ENOMEM;
257
258 err = of_property_read_u32_array(node, name[i], output,
259 num_outputs);
260 if (err)
261 return err;
262
263 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
264 if (!pwm_map)
265 return -ENOMEM;
266
267 pwm_map->output = output;
268 pwm_map->num_outputs = num_outputs;
269 pdata->pwms[i] = pwm_map;
270
271 count++;
272 }
273
274 if (count == 0)
275 return -ENODATA;
276
277 lp3943_pwm->pdata = pdata;
278 return 0;
279 }
280
lp3943_pwm_probe(struct platform_device * pdev)281 static int lp3943_pwm_probe(struct platform_device *pdev)
282 {
283 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
284 struct lp3943_pwm *lp3943_pwm;
285 int ret;
286
287 lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
288 if (!lp3943_pwm)
289 return -ENOMEM;
290
291 lp3943_pwm->pdata = lp3943->pdata;
292 if (!lp3943_pwm->pdata) {
293 if (IS_ENABLED(CONFIG_OF))
294 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
295 else
296 ret = -ENODEV;
297
298 if (ret)
299 return ret;
300 }
301
302 lp3943_pwm->lp3943 = lp3943;
303 lp3943_pwm->chip.dev = &pdev->dev;
304 lp3943_pwm->chip.ops = &lp3943_pwm_ops;
305 lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
306
307 return devm_pwmchip_add(&pdev->dev, &lp3943_pwm->chip);
308 }
309
310 #ifdef CONFIG_OF
311 static const struct of_device_id lp3943_pwm_of_match[] = {
312 { .compatible = "ti,lp3943-pwm", },
313 { }
314 };
315 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
316 #endif
317
318 static struct platform_driver lp3943_pwm_driver = {
319 .probe = lp3943_pwm_probe,
320 .driver = {
321 .name = "lp3943-pwm",
322 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
323 },
324 };
325 module_platform_driver(lp3943_pwm_driver);
326
327 MODULE_DESCRIPTION("LP3943 PWM driver");
328 MODULE_ALIAS("platform:lp3943-pwm");
329 MODULE_AUTHOR("Milo Kim");
330 MODULE_LICENSE("GPL");
331