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/of_device.h>
14 #include <linux/platform_device.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 pwm_chip chip;
34 struct clk *clk;
35 struct clk *pclk;
36 const struct rockchip_pwm_data *data;
37 void __iomem *base;
38 };
39
40 struct rockchip_pwm_regs {
41 unsigned long duty;
42 unsigned long period;
43 unsigned long cntr;
44 unsigned long ctrl;
45 };
46
47 struct rockchip_pwm_data {
48 struct rockchip_pwm_regs regs;
49 unsigned int prescaler;
50 bool supports_polarity;
51 bool supports_lock;
52 u32 enable_conf;
53 };
54
to_rockchip_pwm_chip(struct pwm_chip * chip)55 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *chip)
56 {
57 return container_of(chip, struct rockchip_pwm_chip, chip);
58 }
59
rockchip_pwm_get_state(struct pwm_chip * chip,struct pwm_device * pwm,struct pwm_state * state)60 static int rockchip_pwm_get_state(struct pwm_chip *chip,
61 struct pwm_device *pwm,
62 struct pwm_state *state)
63 {
64 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
65 u32 enable_conf = pc->data->enable_conf;
66 unsigned long clk_rate;
67 u64 tmp;
68 u32 val;
69 int ret;
70
71 ret = clk_enable(pc->pclk);
72 if (ret)
73 return ret;
74
75 ret = clk_enable(pc->clk);
76 if (ret)
77 return ret;
78
79 clk_rate = clk_get_rate(pc->clk);
80
81 tmp = readl_relaxed(pc->base + pc->data->regs.period);
82 tmp *= pc->data->prescaler * NSEC_PER_SEC;
83 state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
84
85 tmp = readl_relaxed(pc->base + pc->data->regs.duty);
86 tmp *= pc->data->prescaler * NSEC_PER_SEC;
87 state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
88
89 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
90 state->enabled = (val & enable_conf) == enable_conf;
91
92 if (pc->data->supports_polarity && !(val & PWM_DUTY_POSITIVE))
93 state->polarity = PWM_POLARITY_INVERSED;
94 else
95 state->polarity = PWM_POLARITY_NORMAL;
96
97 clk_disable(pc->clk);
98 clk_disable(pc->pclk);
99
100 return 0;
101 }
102
rockchip_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)103 static void rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
104 const struct pwm_state *state)
105 {
106 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
107 unsigned long period, duty;
108 u64 clk_rate, div;
109 u32 ctrl;
110
111 clk_rate = clk_get_rate(pc->clk);
112
113 /*
114 * Since period and duty cycle registers have a width of 32
115 * bits, every possible input period can be obtained using the
116 * default prescaler value for all practical clock rate values.
117 */
118 div = clk_rate * state->period;
119 period = DIV_ROUND_CLOSEST_ULL(div,
120 pc->data->prescaler * NSEC_PER_SEC);
121
122 div = clk_rate * state->duty_cycle;
123 duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
124
125 /*
126 * Lock the period and duty of previous configuration, then
127 * change the duty and period, that would not be effective.
128 */
129 ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
130 if (pc->data->supports_lock) {
131 ctrl |= PWM_LOCK_EN;
132 writel_relaxed(ctrl, pc->base + pc->data->regs.ctrl);
133 }
134
135 writel(period, pc->base + pc->data->regs.period);
136 writel(duty, pc->base + pc->data->regs.duty);
137
138 if (pc->data->supports_polarity) {
139 ctrl &= ~PWM_POLARITY_MASK;
140 if (state->polarity == PWM_POLARITY_INVERSED)
141 ctrl |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
142 else
143 ctrl |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
144 }
145
146 /*
147 * Unlock and set polarity at the same time,
148 * the configuration of duty, period and polarity
149 * would be effective together at next period.
150 */
151 if (pc->data->supports_lock)
152 ctrl &= ~PWM_LOCK_EN;
153
154 writel(ctrl, pc->base + pc->data->regs.ctrl);
155 }
156
rockchip_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm,bool enable)157 static int rockchip_pwm_enable(struct pwm_chip *chip,
158 struct pwm_device *pwm,
159 bool enable)
160 {
161 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
162 u32 enable_conf = pc->data->enable_conf;
163 int ret;
164 u32 val;
165
166 if (enable) {
167 ret = clk_enable(pc->clk);
168 if (ret)
169 return ret;
170 }
171
172 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
173
174 if (enable)
175 val |= enable_conf;
176 else
177 val &= ~enable_conf;
178
179 writel_relaxed(val, pc->base + pc->data->regs.ctrl);
180
181 if (!enable)
182 clk_disable(pc->clk);
183
184 return 0;
185 }
186
rockchip_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)187 static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
188 const struct pwm_state *state)
189 {
190 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
191 struct pwm_state curstate;
192 bool enabled;
193 int ret = 0;
194
195 ret = clk_enable(pc->pclk);
196 if (ret)
197 return ret;
198
199 ret = clk_enable(pc->clk);
200 if (ret)
201 return ret;
202
203 pwm_get_state(pwm, &curstate);
204 enabled = curstate.enabled;
205
206 if (state->polarity != curstate.polarity && enabled &&
207 !pc->data->supports_lock) {
208 ret = rockchip_pwm_enable(chip, pwm, false);
209 if (ret)
210 goto out;
211 enabled = false;
212 }
213
214 rockchip_pwm_config(chip, pwm, state);
215 if (state->enabled != enabled) {
216 ret = rockchip_pwm_enable(chip, pwm, state->enabled);
217 if (ret)
218 goto out;
219 }
220
221 out:
222 clk_disable(pc->clk);
223 clk_disable(pc->pclk);
224
225 return ret;
226 }
227
228 static const struct pwm_ops rockchip_pwm_ops = {
229 .get_state = rockchip_pwm_get_state,
230 .apply = rockchip_pwm_apply,
231 .owner = THIS_MODULE,
232 };
233
234 static const struct rockchip_pwm_data pwm_data_v1 = {
235 .regs = {
236 .duty = 0x04,
237 .period = 0x08,
238 .cntr = 0x00,
239 .ctrl = 0x0c,
240 },
241 .prescaler = 2,
242 .supports_polarity = false,
243 .supports_lock = false,
244 .enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN,
245 };
246
247 static const struct rockchip_pwm_data pwm_data_v2 = {
248 .regs = {
249 .duty = 0x08,
250 .period = 0x04,
251 .cntr = 0x00,
252 .ctrl = 0x0c,
253 },
254 .prescaler = 1,
255 .supports_polarity = true,
256 .supports_lock = false,
257 .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
258 PWM_CONTINUOUS,
259 };
260
261 static const struct rockchip_pwm_data pwm_data_vop = {
262 .regs = {
263 .duty = 0x08,
264 .period = 0x04,
265 .cntr = 0x0c,
266 .ctrl = 0x00,
267 },
268 .prescaler = 1,
269 .supports_polarity = true,
270 .supports_lock = false,
271 .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
272 PWM_CONTINUOUS,
273 };
274
275 static const struct rockchip_pwm_data pwm_data_v3 = {
276 .regs = {
277 .duty = 0x08,
278 .period = 0x04,
279 .cntr = 0x00,
280 .ctrl = 0x0c,
281 },
282 .prescaler = 1,
283 .supports_polarity = true,
284 .supports_lock = true,
285 .enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
286 PWM_CONTINUOUS,
287 };
288
289 static const struct of_device_id rockchip_pwm_dt_ids[] = {
290 { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
291 { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
292 { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
293 { .compatible = "rockchip,rk3328-pwm", .data = &pwm_data_v3},
294 { /* sentinel */ }
295 };
296 MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
297
rockchip_pwm_probe(struct platform_device * pdev)298 static int rockchip_pwm_probe(struct platform_device *pdev)
299 {
300 const struct of_device_id *id;
301 struct rockchip_pwm_chip *pc;
302 u32 enable_conf, ctrl;
303 bool enabled;
304 int ret, count;
305
306 id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
307 if (!id)
308 return -EINVAL;
309
310 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
311 if (!pc)
312 return -ENOMEM;
313
314 pc->base = devm_platform_ioremap_resource(pdev, 0);
315 if (IS_ERR(pc->base))
316 return PTR_ERR(pc->base);
317
318 pc->clk = devm_clk_get(&pdev->dev, "pwm");
319 if (IS_ERR(pc->clk)) {
320 pc->clk = devm_clk_get(&pdev->dev, NULL);
321 if (IS_ERR(pc->clk))
322 return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk),
323 "Can't get PWM clk\n");
324 }
325
326 count = of_count_phandle_with_args(pdev->dev.of_node,
327 "clocks", "#clock-cells");
328 if (count == 2)
329 pc->pclk = devm_clk_get(&pdev->dev, "pclk");
330 else
331 pc->pclk = pc->clk;
332
333 if (IS_ERR(pc->pclk))
334 return dev_err_probe(&pdev->dev, PTR_ERR(pc->pclk), "Can't get APB clk\n");
335
336 ret = clk_prepare_enable(pc->clk);
337 if (ret)
338 return dev_err_probe(&pdev->dev, ret, "Can't prepare enable PWM clk\n");
339
340 ret = clk_prepare_enable(pc->pclk);
341 if (ret) {
342 dev_err_probe(&pdev->dev, ret, "Can't prepare enable APB clk\n");
343 goto err_clk;
344 }
345
346 platform_set_drvdata(pdev, pc);
347
348 pc->data = id->data;
349 pc->chip.dev = &pdev->dev;
350 pc->chip.ops = &rockchip_pwm_ops;
351 pc->chip.npwm = 1;
352
353 enable_conf = pc->data->enable_conf;
354 ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
355 enabled = (ctrl & enable_conf) == enable_conf;
356
357 ret = pwmchip_add(&pc->chip);
358 if (ret < 0) {
359 dev_err_probe(&pdev->dev, ret, "pwmchip_add() failed\n");
360 goto err_pclk;
361 }
362
363 /* Keep the PWM clk enabled if the PWM appears to be up and running. */
364 if (!enabled)
365 clk_disable(pc->clk);
366
367 clk_disable(pc->pclk);
368
369 return 0;
370
371 err_pclk:
372 clk_disable_unprepare(pc->pclk);
373 err_clk:
374 clk_disable_unprepare(pc->clk);
375
376 return ret;
377 }
378
rockchip_pwm_remove(struct platform_device * pdev)379 static void rockchip_pwm_remove(struct platform_device *pdev)
380 {
381 struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
382
383 pwmchip_remove(&pc->chip);
384
385 clk_unprepare(pc->pclk);
386 clk_unprepare(pc->clk);
387 }
388
389 static struct platform_driver rockchip_pwm_driver = {
390 .driver = {
391 .name = "rockchip-pwm",
392 .of_match_table = rockchip_pwm_dt_ids,
393 },
394 .probe = rockchip_pwm_probe,
395 .remove_new = rockchip_pwm_remove,
396 };
397 module_platform_driver(rockchip_pwm_driver);
398
399 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
400 MODULE_DESCRIPTION("Rockchip SoC PWM driver");
401 MODULE_LICENSE("GPL v2");
402