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
33 struct 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
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 const struct pwm_ops *ops;
51
52 void (*set_enable)(struct pwm_chip *chip,
53 struct pwm_device *pwm, bool enable);
54 };
55
to_rockchip_pwm_chip(struct pwm_chip * c)56 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
57 {
58 return container_of(c, struct rockchip_pwm_chip, chip);
59 }
60
rockchip_pwm_set_enable_v1(struct pwm_chip * chip,struct pwm_device * pwm,bool enable)61 static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
62 struct pwm_device *pwm, bool enable)
63 {
64 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
65 u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
66 u32 val;
67
68 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
69
70 if (enable)
71 val |= enable_conf;
72 else
73 val &= ~enable_conf;
74
75 writel_relaxed(val, pc->base + pc->data->regs.ctrl);
76 }
77
rockchip_pwm_set_enable_v2(struct pwm_chip * chip,struct pwm_device * pwm,bool enable)78 static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
79 struct pwm_device *pwm, bool enable)
80 {
81 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
82 u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
83 PWM_CONTINUOUS;
84 u32 val;
85
86 if (pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED)
87 enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
88 else
89 enable_conf |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
90
91 val = readl_relaxed(pc->base + pc->data->regs.ctrl);
92
93 if (enable)
94 val |= enable_conf;
95 else
96 val &= ~enable_conf;
97
98 writel_relaxed(val, pc->base + pc->data->regs.ctrl);
99 }
100
rockchip_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)101 static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
102 int duty_ns, int period_ns)
103 {
104 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
105 unsigned long period, duty;
106 u64 clk_rate, div;
107 int ret;
108
109 clk_rate = clk_get_rate(pc->clk);
110
111 /*
112 * Since period and duty cycle registers have a width of 32
113 * bits, every possible input period can be obtained using the
114 * default prescaler value for all practical clock rate values.
115 */
116 div = clk_rate * period_ns;
117 do_div(div, pc->data->prescaler * NSEC_PER_SEC);
118 period = div;
119
120 div = clk_rate * duty_ns;
121 do_div(div, pc->data->prescaler * NSEC_PER_SEC);
122 duty = div;
123
124 ret = clk_enable(pc->clk);
125 if (ret)
126 return ret;
127
128 writel(period, pc->base + pc->data->regs.period);
129 writel(duty, pc->base + pc->data->regs.duty);
130 writel(0, pc->base + pc->data->regs.cntr);
131
132 clk_disable(pc->clk);
133
134 return 0;
135 }
136
rockchip_pwm_set_polarity(struct pwm_chip * chip,struct pwm_device * pwm,enum pwm_polarity polarity)137 static int rockchip_pwm_set_polarity(struct pwm_chip *chip,
138 struct pwm_device *pwm,
139 enum pwm_polarity polarity)
140 {
141 /*
142 * No action needed here because pwm->polarity will be set by the core
143 * and the core will only change polarity when the PWM is not enabled.
144 * We'll handle things in set_enable().
145 */
146
147 return 0;
148 }
149
rockchip_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)150 static int rockchip_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
151 {
152 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
153 int ret;
154
155 ret = clk_enable(pc->clk);
156 if (ret)
157 return ret;
158
159 pc->data->set_enable(chip, pwm, true);
160
161 return 0;
162 }
163
rockchip_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)164 static void rockchip_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
165 {
166 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
167
168 pc->data->set_enable(chip, pwm, false);
169
170 clk_disable(pc->clk);
171 }
172
173 static const struct pwm_ops rockchip_pwm_ops_v1 = {
174 .config = rockchip_pwm_config,
175 .enable = rockchip_pwm_enable,
176 .disable = rockchip_pwm_disable,
177 .owner = THIS_MODULE,
178 };
179
180 static const struct pwm_ops rockchip_pwm_ops_v2 = {
181 .config = rockchip_pwm_config,
182 .set_polarity = rockchip_pwm_set_polarity,
183 .enable = rockchip_pwm_enable,
184 .disable = rockchip_pwm_disable,
185 .owner = THIS_MODULE,
186 };
187
188 static const struct rockchip_pwm_data pwm_data_v1 = {
189 .regs = {
190 .duty = 0x04,
191 .period = 0x08,
192 .cntr = 0x00,
193 .ctrl = 0x0c,
194 },
195 .prescaler = 2,
196 .ops = &rockchip_pwm_ops_v1,
197 .set_enable = rockchip_pwm_set_enable_v1,
198 };
199
200 static const struct rockchip_pwm_data pwm_data_v2 = {
201 .regs = {
202 .duty = 0x08,
203 .period = 0x04,
204 .cntr = 0x00,
205 .ctrl = 0x0c,
206 },
207 .prescaler = 1,
208 .ops = &rockchip_pwm_ops_v2,
209 .set_enable = rockchip_pwm_set_enable_v2,
210 };
211
212 static const struct rockchip_pwm_data pwm_data_vop = {
213 .regs = {
214 .duty = 0x08,
215 .period = 0x04,
216 .cntr = 0x0c,
217 .ctrl = 0x00,
218 },
219 .prescaler = 1,
220 .ops = &rockchip_pwm_ops_v2,
221 .set_enable = rockchip_pwm_set_enable_v2,
222 };
223
224 static const struct of_device_id rockchip_pwm_dt_ids[] = {
225 { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
226 { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
227 { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
228 { /* sentinel */ }
229 };
230 MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
231
rockchip_pwm_probe(struct platform_device * pdev)232 static int rockchip_pwm_probe(struct platform_device *pdev)
233 {
234 const struct of_device_id *id;
235 struct rockchip_pwm_chip *pc;
236 struct resource *r;
237 int ret;
238
239 id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
240 if (!id)
241 return -EINVAL;
242
243 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
244 if (!pc)
245 return -ENOMEM;
246
247 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
248 pc->base = devm_ioremap_resource(&pdev->dev, r);
249 if (IS_ERR(pc->base))
250 return PTR_ERR(pc->base);
251
252 pc->clk = devm_clk_get(&pdev->dev, NULL);
253 if (IS_ERR(pc->clk))
254 return PTR_ERR(pc->clk);
255
256 ret = clk_prepare(pc->clk);
257 if (ret)
258 return ret;
259
260 platform_set_drvdata(pdev, pc);
261
262 pc->data = id->data;
263 pc->chip.dev = &pdev->dev;
264 pc->chip.ops = pc->data->ops;
265 pc->chip.base = -1;
266 pc->chip.npwm = 1;
267
268 if (pc->data->ops->set_polarity) {
269 pc->chip.of_xlate = of_pwm_xlate_with_flags;
270 pc->chip.of_pwm_n_cells = 3;
271 }
272
273 ret = pwmchip_add(&pc->chip);
274 if (ret < 0) {
275 clk_unprepare(pc->clk);
276 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
277 }
278
279 return ret;
280 }
281
rockchip_pwm_remove(struct platform_device * pdev)282 static int rockchip_pwm_remove(struct platform_device *pdev)
283 {
284 struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
285
286 clk_unprepare(pc->clk);
287
288 return pwmchip_remove(&pc->chip);
289 }
290
291 static struct platform_driver rockchip_pwm_driver = {
292 .driver = {
293 .name = "rockchip-pwm",
294 .of_match_table = rockchip_pwm_dt_ids,
295 },
296 .probe = rockchip_pwm_probe,
297 .remove = rockchip_pwm_remove,
298 };
299 module_platform_driver(rockchip_pwm_driver);
300
301 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
302 MODULE_DESCRIPTION("Rockchip SoC PWM driver");
303 MODULE_LICENSE("GPL v2");
304