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 | |
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 * |
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(size: sizeof(*pwm_map), GFP_KERNEL); |
42 | if (!pwm_map) |
43 | return ERR_PTR(error: -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(nr: offset, addr: &lp3943->pin_used)) { |
53 | kfree(objp: pwm_map); |
54 | return ERR_PTR(error: -EBUSY); |
55 | } |
56 | } |
57 | |
58 | return pwm_map; |
59 | } |
60 | |
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, hwpwm: pwm->hwpwm); |
67 | if (IS_ERR(ptr: pwm_map)) |
68 | return PTR_ERR(ptr: pwm_map); |
69 | |
70 | return pwm_set_chip_data(pwm, data: pwm_map); |
71 | } |
72 | |
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(nr: offset, addr: &lp3943->pin_used); |
82 | } |
83 | |
84 | kfree(objp: pwm_map); |
85 | } |
86 | |
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 | |
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: reg_prescale, data: 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: reg_duty, data: val); |
137 | } |
138 | |
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, reg: mux[index].reg, |
150 | mask: mux[index].mask, |
151 | data: val << mux[index].shift); |
152 | if (err) |
153 | return err; |
154 | } |
155 | |
156 | return 0; |
157 | } |
158 | |
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 | |
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 | |
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, duty_ns: state->duty_cycle, period_ns: 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 | |
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, size: 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: name[i], lenp: &proplen)) |
247 | continue; |
248 | |
249 | num_outputs = proplen / sizeof(u32); |
250 | if (num_outputs == 0) |
251 | continue; |
252 | |
253 | output = devm_kcalloc(dev, n: num_outputs, size: sizeof(*output), |
254 | GFP_KERNEL); |
255 | if (!output) |
256 | return -ENOMEM; |
257 | |
258 | err = of_property_read_u32_array(np: node, propname: name[i], out_values: output, |
259 | sz: num_outputs); |
260 | if (err) |
261 | return err; |
262 | |
263 | pwm_map = devm_kzalloc(dev, size: 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 | |
281 | static int lp3943_pwm_probe(struct platform_device *pdev) |
282 | { |
283 | struct lp3943 *lp3943 = dev_get_drvdata(dev: pdev->dev.parent); |
284 | struct lp3943_pwm *lp3943_pwm; |
285 | int ret; |
286 | |
287 | lp3943_pwm = devm_kzalloc(dev: &pdev->dev, size: 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(dev: &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(dev: &pdev->dev, chip: &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 | |