1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * PWM driver for Rockchip SoCs
4 *
5 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
6 * Copyright (C) 2014 ROCKCHIP, Inc.
7 */
8
9 #include <linux/clk.h>
10 #include <linux/io.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/property.h>
15 #include <linux/pwm.h>
16 #include <linux/time.h>
17
18 #define PWM_CTRL_TIMER_EN (1 << 0)
19 #define PWM_CTRL_OUTPUT_EN (1 << 3)
20
21 #define PWM_ENABLE (1 << 0)
22 #define PWM_CONTINUOUS (1 << 1)
23 #define PWM_DUTY_POSITIVE (1 << 3)
24 #define PWM_DUTY_NEGATIVE (0 << 3)
25 #define PWM_INACTIVE_NEGATIVE (0 << 4)
26 #define PWM_INACTIVE_POSITIVE (1 << 4)
27 #define PWM_POLARITY_MASK (PWM_DUTY_POSITIVE | PWM_INACTIVE_POSITIVE)
28 #define PWM_OUTPUT_LEFT (0 << 5)
29 #define PWM_LOCK_EN (1 << 6)
30 #define PWM_LP_DISABLE (0 << 8)
31
32 struct rockchip_pwm_chip {
33 struct clk *clk;
34 struct clk *pclk;
35 const struct rockchip_pwm_data *data;
36 void __iomem *base;
37 };
38
39 struct rockchip_pwm_regs {
40 unsigned long duty;
41 unsigned long period;
42 unsigned long cntr;
43 unsigned long ctrl;
44 };
45
46 struct rockchip_pwm_data {
47 struct rockchip_pwm_regs regs;
48 unsigned int prescaler;
49 bool supports_polarity;
50 bool supports_lock;
51 u32 enable_conf;
52 };
53
to_rockchip_pwm_chip(struct pwm_chip * chip)54 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *chip)
55 {
56 return pwmchip_get_drvdata(chip);
57 }
58
rockchip_pwm_get_state(struct pwm_chip * chip,struct pwm_device * pwm,struct pwm_state * state)59 static int rockchip_pwm_get_state(struct pwm_chip *chip,
60 struct pwm_device *pwm,
61 struct pwm_state *state)
62 {
63 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
64 u32 enable_conf = pc->data->enable_conf;
65 unsigned long clk_rate;
66 u64 tmp;
67 u32 val;
68 int ret;
69
70 ret = clk_enable(pc->pclk);
71 if (ret)
72 return ret;
73
74 ret = clk_enable(pc->clk);
75 if (ret)
76 return ret;
77
78 clk_rate = clk_get_rate(pc->clk);
79
80 tmp = readl_relaxed(pc->base + pc->data->regs.period);
81 tmp *= pc->data->prescaler * NSEC_PER_SEC;
82 state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
83
84 tmp = readl_relaxed(pc->base + pc->data->regs.duty);
85 tmp *= pc->data->prescaler * NSEC_PER_SEC;
86 state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
87
88 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
89 state->enabled = (val & enable_conf) == enable_conf;
90
91 if (pc->data->supports_polarity && !(val & PWM_DUTY_POSITIVE))
92 state->polarity = PWM_POLARITY_INVERSED;
93 else
94 state->polarity = PWM_POLARITY_NORMAL;
95
96 clk_disable(pc->clk);
97 clk_disable(pc->pclk);
98
99 return 0;
100 }
101
rockchip_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)102 static void rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
103 const struct pwm_state *state)
104 {
105 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
106 unsigned long period, duty;
107 u64 clk_rate, div;
108 u32 ctrl;
109
110 clk_rate = clk_get_rate(pc->clk);
111
112 /*
113 * Since period and duty cycle registers have a width of 32
114 * bits, every possible input period can be obtained using the
115 * default prescaler value for all practical clock rate values.
116 */
117 div = clk_rate * state->period;
118 period = DIV_ROUND_CLOSEST_ULL(div,
119 pc->data->prescaler * NSEC_PER_SEC);
120
121 div = clk_rate * state->duty_cycle;
122 duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
123
124 /*
125 * Lock the period and duty of previous configuration, then
126 * change the duty and period, that would not be effective.
127 */
128 ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
129 if (pc->data->supports_lock) {
130 ctrl |= PWM_LOCK_EN;
131 writel_relaxed(ctrl, pc->base + pc->data->regs.ctrl);
132 }
133
134 writel(period, pc->base + pc->data->regs.period);
135 writel(duty, pc->base + pc->data->regs.duty);
136
137 if (pc->data->supports_polarity) {
138 ctrl &= ~PWM_POLARITY_MASK;
139 if (state->polarity == PWM_POLARITY_INVERSED)
140 ctrl |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
141 else
142 ctrl |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
143 }
144
145 /*
146 * Unlock and set polarity at the same time,
147 * the configuration of duty, period and polarity
148 * would be effective together at next period.
149 */
150 if (pc->data->supports_lock)
151 ctrl &= ~PWM_LOCK_EN;
152
153 writel(ctrl, pc->base + pc->data->regs.ctrl);
154 }
155
rockchip_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm,bool enable)156 static int rockchip_pwm_enable(struct pwm_chip *chip,
157 struct pwm_device *pwm,
158 bool enable)
159 {
160 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
161 u32 enable_conf = pc->data->enable_conf;
162 int ret;
163 u32 val;
164
165 if (enable) {
166 ret = clk_enable(pc->clk);
167 if (ret)
168 return ret;
169 }
170
171 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
172
173 if (enable)
174 val |= enable_conf;
175 else
176 val &= ~enable_conf;
177
178 writel_relaxed(val, pc->base + pc->data->regs.ctrl);
179
180 if (!enable)
181 clk_disable(pc->clk);
182
183 return 0;
184 }
185
rockchip_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)186 static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
187 const struct pwm_state *state)
188 {
189 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
190 struct pwm_state curstate;
191 bool enabled;
192 int ret = 0;
193
194 ret = clk_enable(pc->pclk);
195 if (ret)
196 return ret;
197
198 ret = clk_enable(pc->clk);
199 if (ret)
200 return ret;
201
202 pwm_get_state(pwm, &curstate);
203 enabled = curstate.enabled;
204
205 if (state->polarity != curstate.polarity && enabled &&
206 !pc->data->supports_lock) {
207 ret = rockchip_pwm_enable(chip, pwm, false);
208 if (ret)
209 goto out;
210 enabled = false;
211 }
212
213 rockchip_pwm_config(chip, pwm, state);
214 if (state->enabled != enabled) {
215 ret = rockchip_pwm_enable(chip, pwm, state->enabled);
216 if (ret)
217 goto out;
218 }
219
220 out:
221 clk_disable(pc->clk);
222 clk_disable(pc->pclk);
223
224 return ret;
225 }
226
227 static const struct pwm_ops rockchip_pwm_ops = {
228 .get_state = rockchip_pwm_get_state,
229 .apply = rockchip_pwm_apply,
230 };
231
232 static const struct rockchip_pwm_data pwm_data_v1 = {
233 .regs = {
234 .duty = 0x04,
235 .period = 0x08,
236 .cntr = 0x00,
237 .ctrl = 0x0c,
238 },
239 .prescaler = 2,
240 .supports_polarity = false,
241 .supports_lock = false,
242 .enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN,
243 };
244
245 static const struct rockchip_pwm_data pwm_data_v2 = {
246 .regs = {
247 .duty = 0x08,
248 .period = 0x04,
249 .cntr = 0x00,
250 .ctrl = 0x0c,
251 },
252 .prescaler = 1,
253 .supports_polarity = true,
254 .supports_lock = false,
255 .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
256 PWM_CONTINUOUS,
257 };
258
259 static const struct rockchip_pwm_data pwm_data_vop = {
260 .regs = {
261 .duty = 0x08,
262 .period = 0x04,
263 .cntr = 0x0c,
264 .ctrl = 0x00,
265 },
266 .prescaler = 1,
267 .supports_polarity = true,
268 .supports_lock = false,
269 .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
270 PWM_CONTINUOUS,
271 };
272
273 static const struct rockchip_pwm_data pwm_data_v3 = {
274 .regs = {
275 .duty = 0x08,
276 .period = 0x04,
277 .cntr = 0x00,
278 .ctrl = 0x0c,
279 },
280 .prescaler = 1,
281 .supports_polarity = true,
282 .supports_lock = true,
283 .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
284 PWM_CONTINUOUS,
285 };
286
287 static const struct of_device_id rockchip_pwm_dt_ids[] = {
288 { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
289 { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
290 { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
291 { .compatible = "rockchip,rk3328-pwm", .data = &pwm_data_v3},
292 { /* sentinel */ }
293 };
294 MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
295
rockchip_pwm_probe(struct platform_device * pdev)296 static int rockchip_pwm_probe(struct platform_device *pdev)
297 {
298 struct pwm_chip *chip;
299 struct rockchip_pwm_chip *pc;
300 u32 enable_conf, ctrl;
301 bool enabled;
302 int ret, count;
303
304 chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*pc));
305 if (IS_ERR(chip))
306 return PTR_ERR(chip);
307 pc = to_rockchip_pwm_chip(chip);
308
309 pc->base = devm_platform_ioremap_resource(pdev, 0);
310 if (IS_ERR(pc->base))
311 return PTR_ERR(pc->base);
312
313 pc->clk = devm_clk_get(&pdev->dev, "pwm");
314 if (IS_ERR(pc->clk)) {
315 pc->clk = devm_clk_get(&pdev->dev, NULL);
316 if (IS_ERR(pc->clk))
317 return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk),
318 "Can't get PWM clk\n");
319 }
320
321 count = of_count_phandle_with_args(pdev->dev.of_node,
322 "clocks", "#clock-cells");
323 if (count == 2)
324 pc->pclk = devm_clk_get(&pdev->dev, "pclk");
325 else
326 pc->pclk = pc->clk;
327
328 if (IS_ERR(pc->pclk))
329 return dev_err_probe(&pdev->dev, PTR_ERR(pc->pclk), "Can't get APB clk\n");
330
331 ret = clk_prepare_enable(pc->clk);
332 if (ret)
333 return dev_err_probe(&pdev->dev, ret, "Can't prepare enable PWM clk\n");
334
335 ret = clk_prepare_enable(pc->pclk);
336 if (ret) {
337 dev_err_probe(&pdev->dev, ret, "Can't prepare enable APB clk\n");
338 goto err_clk;
339 }
340
341 platform_set_drvdata(pdev, chip);
342
343 pc->data = device_get_match_data(&pdev->dev);
344 chip->ops = &rockchip_pwm_ops;
345
346 enable_conf = pc->data->enable_conf;
347 ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
348 enabled = (ctrl & enable_conf) == enable_conf;
349
350 ret = pwmchip_add(chip);
351 if (ret < 0) {
352 dev_err_probe(&pdev->dev, ret, "pwmchip_add() failed\n");
353 goto err_pclk;
354 }
355
356 /* Keep the PWM clk enabled if the PWM appears to be up and running. */
357 if (!enabled)
358 clk_disable(pc->clk);
359
360 clk_disable(pc->pclk);
361
362 return 0;
363
364 err_pclk:
365 clk_disable_unprepare(pc->pclk);
366 err_clk:
367 clk_disable_unprepare(pc->clk);
368
369 return ret;
370 }
371
rockchip_pwm_remove(struct platform_device * pdev)372 static void rockchip_pwm_remove(struct platform_device *pdev)
373 {
374 struct pwm_chip *chip = platform_get_drvdata(pdev);
375 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
376
377 pwmchip_remove(chip);
378
379 clk_unprepare(pc->pclk);
380 clk_unprepare(pc->clk);
381 }
382
383 static struct platform_driver rockchip_pwm_driver = {
384 .driver = {
385 .name = "rockchip-pwm",
386 .of_match_table = rockchip_pwm_dt_ids,
387 },
388 .probe = rockchip_pwm_probe,
389 .remove = rockchip_pwm_remove,
390 };
391 module_platform_driver(rockchip_pwm_driver);
392
393 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
394 MODULE_DESCRIPTION("Rockchip SoC PWM driver");
395 MODULE_LICENSE("GPL v2");
396