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1/*
2 * PWM driver for Rockchip SoCs
3 *
4 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
5 * Copyright (C) 2014 ROCKCHIP, Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
10 */
11
12#include <linux/clk.h>
13#include <linux/io.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_device.h>
17#include <linux/platform_device.h>
18#include <linux/pwm.h>
19#include <linux/time.h>
20
21#define PWM_CTRL_TIMER_EN (1 << 0)
22#define PWM_CTRL_OUTPUT_EN (1 << 3)
23
24#define PWM_ENABLE (1 << 0)
25#define PWM_CONTINUOUS (1 << 1)
26#define PWM_DUTY_POSITIVE (1 << 3)
27#define PWM_DUTY_NEGATIVE (0 << 3)
28#define PWM_INACTIVE_NEGATIVE (0 << 4)
29#define PWM_INACTIVE_POSITIVE (1 << 4)
30#define PWM_OUTPUT_LEFT (0 << 5)
31#define PWM_LP_DISABLE (0 << 8)
32
33struct rockchip_pwm_chip {
34 struct pwm_chip chip;
35 struct clk *clk;
36 const struct rockchip_pwm_data *data;
37 void __iomem *base;
38};
39
40struct rockchip_pwm_regs {
41 unsigned long duty;
42 unsigned long period;
43 unsigned long cntr;
44 unsigned long ctrl;
45};
46
47struct rockchip_pwm_data {
48 struct rockchip_pwm_regs regs;
49 unsigned int prescaler;
50 bool supports_polarity;
51 const struct pwm_ops *ops;
52
53 void (*set_enable)(struct pwm_chip *chip,
54 struct pwm_device *pwm, bool enable,
55 enum pwm_polarity polarity);
56 void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
57 struct pwm_state *state);
58};
59
60static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
61{
62 return container_of(c, struct rockchip_pwm_chip, chip);
63}
64
65static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
66 struct pwm_device *pwm, bool enable,
67 enum pwm_polarity polarity)
68{
69 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
70 u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
71 u32 val;
72
73 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
74
75 if (enable)
76 val |= enable_conf;
77 else
78 val &= ~enable_conf;
79
80 writel_relaxed(val, pc->base + pc->data->regs.ctrl);
81}
82
83static void rockchip_pwm_get_state_v1(struct pwm_chip *chip,
84 struct pwm_device *pwm,
85 struct pwm_state *state)
86{
87 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
88 u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
89 u32 val;
90
91 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
92 if ((val & enable_conf) == enable_conf)
93 state->enabled = true;
94}
95
96static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
97 struct pwm_device *pwm, bool enable,
98 enum pwm_polarity polarity)
99{
100 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
101 u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
102 PWM_CONTINUOUS;
103 u32 val;
104
105 if (polarity == PWM_POLARITY_INVERSED)
106 enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
107 else
108 enable_conf |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
109
110 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
111
112 if (enable)
113 val |= enable_conf;
114 else
115 val &= ~enable_conf;
116
117 writel_relaxed(val, pc->base + pc->data->regs.ctrl);
118}
119
120static void rockchip_pwm_get_state_v2(struct pwm_chip *chip,
121 struct pwm_device *pwm,
122 struct pwm_state *state)
123{
124 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
125 u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
126 PWM_CONTINUOUS;
127 u32 val;
128
129 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
130 if ((val & enable_conf) != enable_conf)
131 return;
132
133 state->enabled = true;
134
135 if (!(val & PWM_DUTY_POSITIVE))
136 state->polarity = PWM_POLARITY_INVERSED;
137}
138
139static void rockchip_pwm_get_state(struct pwm_chip *chip,
140 struct pwm_device *pwm,
141 struct pwm_state *state)
142{
143 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
144 unsigned long clk_rate;
145 u64 tmp;
146 int ret;
147
148 ret = clk_enable(pc->clk);
149 if (ret)
150 return;
151
152 clk_rate = clk_get_rate(pc->clk);
153
154 tmp = readl_relaxed(pc->base + pc->data->regs.period);
155 tmp *= pc->data->prescaler * NSEC_PER_SEC;
156 state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
157
158 tmp = readl_relaxed(pc->base + pc->data->regs.duty);
159 tmp *= pc->data->prescaler * NSEC_PER_SEC;
160 state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
161
162 pc->data->get_state(chip, pwm, state);
163
164 clk_disable(pc->clk);
165}
166
167static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
168 int duty_ns, int period_ns)
169{
170 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
171 unsigned long period, duty;
172 u64 clk_rate, div;
173
174 clk_rate = clk_get_rate(pc->clk);
175
176 /*
177 * Since period and duty cycle registers have a width of 32
178 * bits, every possible input period can be obtained using the
179 * default prescaler value for all practical clock rate values.
180 */
181 div = clk_rate * period_ns;
182 period = DIV_ROUND_CLOSEST_ULL(div,
183 pc->data->prescaler * NSEC_PER_SEC);
184
185 div = clk_rate * duty_ns;
186 duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
187
188 writel(period, pc->base + pc->data->regs.period);
189 writel(duty, pc->base + pc->data->regs.duty);
190
191 return 0;
192}
193
194static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
195 struct pwm_state *state)
196{
197 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
198 struct pwm_state curstate;
199 bool enabled;
200 int ret;
201
202 pwm_get_state(pwm, &curstate);
203 enabled = curstate.enabled;
204
205 ret = clk_enable(pc->clk);
206 if (ret)
207 return ret;
208
209 if (state->polarity != curstate.polarity && enabled) {
210 pc->data->set_enable(chip, pwm, false, state->polarity);
211 enabled = false;
212 }
213
214 ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
215 if (ret) {
216 if (enabled != curstate.enabled)
217 pc->data->set_enable(chip, pwm, !enabled,
218 state->polarity);
219
220 goto out;
221 }
222
223 if (state->enabled != enabled)
224 pc->data->set_enable(chip, pwm, state->enabled,
225 state->polarity);
226
227 /*
228 * Update the state with the real hardware, which can differ a bit
229 * because of period/duty_cycle approximation.
230 */
231 rockchip_pwm_get_state(chip, pwm, state);
232
233out:
234 clk_disable(pc->clk);
235
236 return ret;
237}
238
239static const struct pwm_ops rockchip_pwm_ops_v1 = {
240 .get_state = rockchip_pwm_get_state,
241 .apply = rockchip_pwm_apply,
242 .owner = THIS_MODULE,
243};
244
245static const struct pwm_ops rockchip_pwm_ops_v2 = {
246 .get_state = rockchip_pwm_get_state,
247 .apply = rockchip_pwm_apply,
248 .owner = THIS_MODULE,
249};
250
251static const struct rockchip_pwm_data pwm_data_v1 = {
252 .regs = {
253 .duty = 0x04,
254 .period = 0x08,
255 .cntr = 0x00,
256 .ctrl = 0x0c,
257 },
258 .prescaler = 2,
259 .ops = &rockchip_pwm_ops_v1,
260 .set_enable = rockchip_pwm_set_enable_v1,
261 .get_state = rockchip_pwm_get_state_v1,
262};
263
264static const struct rockchip_pwm_data pwm_data_v2 = {
265 .regs = {
266 .duty = 0x08,
267 .period = 0x04,
268 .cntr = 0x00,
269 .ctrl = 0x0c,
270 },
271 .prescaler = 1,
272 .supports_polarity = true,
273 .ops = &rockchip_pwm_ops_v2,
274 .set_enable = rockchip_pwm_set_enable_v2,
275 .get_state = rockchip_pwm_get_state_v2,
276};
277
278static const struct rockchip_pwm_data pwm_data_vop = {
279 .regs = {
280 .duty = 0x08,
281 .period = 0x04,
282 .cntr = 0x0c,
283 .ctrl = 0x00,
284 },
285 .prescaler = 1,
286 .supports_polarity = true,
287 .ops = &rockchip_pwm_ops_v2,
288 .set_enable = rockchip_pwm_set_enable_v2,
289 .get_state = rockchip_pwm_get_state_v2,
290};
291
292static const struct of_device_id rockchip_pwm_dt_ids[] = {
293 { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
294 { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
295 { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
296 { /* sentinel */ }
297};
298MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
299
300static int rockchip_pwm_probe(struct platform_device *pdev)
301{
302 const struct of_device_id *id;
303 struct rockchip_pwm_chip *pc;
304 struct resource *r;
305 int ret;
306
307 id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
308 if (!id)
309 return -EINVAL;
310
311 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
312 if (!pc)
313 return -ENOMEM;
314
315 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
316 pc->base = devm_ioremap_resource(&pdev->dev, r);
317 if (IS_ERR(pc->base))
318 return PTR_ERR(pc->base);
319
320 pc->clk = devm_clk_get(&pdev->dev, NULL);
321 if (IS_ERR(pc->clk))
322 return PTR_ERR(pc->clk);
323
324 ret = clk_prepare_enable(pc->clk);
325 if (ret)
326 return ret;
327
328 platform_set_drvdata(pdev, pc);
329
330 pc->data = id->data;
331 pc->chip.dev = &pdev->dev;
332 pc->chip.ops = pc->data->ops;
333 pc->chip.base = -1;
334 pc->chip.npwm = 1;
335
336 if (pc->data->supports_polarity) {
337 pc->chip.of_xlate = of_pwm_xlate_with_flags;
338 pc->chip.of_pwm_n_cells = 3;
339 }
340
341 ret = pwmchip_add(&pc->chip);
342 if (ret < 0) {
343 clk_unprepare(pc->clk);
344 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
345 }
346
347 /* Keep the PWM clk enabled if the PWM appears to be up and running. */
348 if (!pwm_is_enabled(pc->chip.pwms))
349 clk_disable(pc->clk);
350
351 return ret;
352}
353
354static int rockchip_pwm_remove(struct platform_device *pdev)
355{
356 struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
357
358 /*
359 * Disable the PWM clk before unpreparing it if the PWM device is still
360 * running. This should only happen when the last PWM user left it
361 * enabled, or when nobody requested a PWM that was previously enabled
362 * by the bootloader.
363 *
364 * FIXME: Maybe the core should disable all PWM devices in
365 * pwmchip_remove(). In this case we'd only have to call
366 * clk_unprepare() after pwmchip_remove().
367 *
368 */
369 if (pwm_is_enabled(pc->chip.pwms))
370 clk_disable(pc->clk);
371
372 clk_unprepare(pc->clk);
373
374 return pwmchip_remove(&pc->chip);
375}
376
377static struct platform_driver rockchip_pwm_driver = {
378 .driver = {
379 .name = "rockchip-pwm",
380 .of_match_table = rockchip_pwm_dt_ids,
381 },
382 .probe = rockchip_pwm_probe,
383 .remove = rockchip_pwm_remove,
384};
385module_platform_driver(rockchip_pwm_driver);
386
387MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
388MODULE_DESCRIPTION("Rockchip SoC PWM driver");
389MODULE_LICENSE("GPL v2");