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/i2c.h>
12 #include <linux/mfd/lp3943.h>
13 #include <linux/module.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,int duty_ns,int period_ns)95 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
96 int duty_ns, int 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 period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
122 val = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
123
124 err = lp3943_write_byte(lp3943, reg_prescale, val);
125 if (err)
126 return err;
127
128 duty_ns = min(duty_ns, period_ns);
129 val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
130
131 return lp3943_write_byte(lp3943, reg_duty, val);
132 }
133
lp3943_pwm_set_mode(struct lp3943_pwm * lp3943_pwm,struct lp3943_pwm_map * pwm_map,u8 val)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
lp3943_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)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
lp3943_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)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
lp3943_pwm_parse_dt(struct device * dev,struct lp3943_pwm * lp3943_pwm)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_kcalloc(dev, num_outputs, sizeof(*output),
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
lp3943_pwm_probe(struct platform_device * pdev)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 lp3943_pwm->chip.base = -1;
280
281 platform_set_drvdata(pdev, lp3943_pwm);
282
283 return pwmchip_add(&lp3943_pwm->chip);
284 }
285
lp3943_pwm_remove(struct platform_device * pdev)286 static int lp3943_pwm_remove(struct platform_device *pdev)
287 {
288 struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
289
290 return pwmchip_remove(&lp3943_pwm->chip);
291 }
292
293 #ifdef CONFIG_OF
294 static const struct of_device_id lp3943_pwm_of_match[] = {
295 { .compatible = "ti,lp3943-pwm", },
296 { }
297 };
298 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
299 #endif
300
301 static struct platform_driver lp3943_pwm_driver = {
302 .probe = lp3943_pwm_probe,
303 .remove = lp3943_pwm_remove,
304 .driver = {
305 .name = "lp3943-pwm",
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");
315