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pwm: rockchip: Fix period and duty cycle approximation
[mirror_ubuntu-bionic-kernel.git] / drivers / pwm / pwm-rockchip.c
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1/*
2 * PWM driver for Rockchip SoCs
3 *
4 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
f6306299 5 * Copyright (C) 2014 ROCKCHIP, Inc.
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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>
f6306299 16#include <linux/of_device.h>
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17#include <linux/platform_device.h>
18#include <linux/pwm.h>
19#include <linux/time.h>
20
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21#define PWM_CTRL_TIMER_EN (1 << 0)
22#define PWM_CTRL_OUTPUT_EN (1 << 3)
23
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24#define PWM_ENABLE (1 << 0)
25#define PWM_CONTINUOUS (1 << 1)
26#define PWM_DUTY_POSITIVE (1 << 3)
7264354c 27#define PWM_DUTY_NEGATIVE (0 << 3)
f6306299 28#define PWM_INACTIVE_NEGATIVE (0 << 4)
7264354c 29#define PWM_INACTIVE_POSITIVE (1 << 4)
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30#define PWM_OUTPUT_LEFT (0 << 5)
31#define PWM_LP_DISABLE (0 << 8)
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32
33struct rockchip_pwm_chip {
34 struct pwm_chip chip;
35 struct clk *clk;
f6306299 36 const struct rockchip_pwm_data *data;
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37 void __iomem *base;
38};
39
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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;
7264354c 50 const struct pwm_ops *ops;
f6306299 51
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52 void (*set_enable)(struct pwm_chip *chip,
53 struct pwm_device *pwm, bool enable);
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54};
55
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56static 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
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61static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
62 struct pwm_device *pwm, bool enable)
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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
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78static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
79 struct pwm_device *pwm, bool enable)
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80{
81 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
82 u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
7264354c 83 PWM_CONTINUOUS;
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84 u32 val;
85
15da7b50 86 if (pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED)
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87 enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
88 else
89 enable_conf |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
90
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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
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101static 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;
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117 period = DIV_ROUND_CLOSEST_ULL(div,
118 pc->data->prescaler * NSEC_PER_SEC);
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119
120 div = clk_rate * duty_ns;
12f9ce4a 121 duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
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122
123 ret = clk_enable(pc->clk);
124 if (ret)
125 return ret;
126
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127 writel(period, pc->base + pc->data->regs.period);
128 writel(duty, pc->base + pc->data->regs.duty);
129 writel(0, pc->base + pc->data->regs.cntr);
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130
131 clk_disable(pc->clk);
132
133 return 0;
134}
135
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136static int rockchip_pwm_set_polarity(struct pwm_chip *chip,
137 struct pwm_device *pwm,
138 enum pwm_polarity polarity)
139{
140 /*
141 * No action needed here because pwm->polarity will be set by the core
142 * and the core will only change polarity when the PWM is not enabled.
143 * We'll handle things in set_enable().
144 */
145
146 return 0;
147}
148
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149static int rockchip_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
150{
151 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
152 int ret;
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153
154 ret = clk_enable(pc->clk);
155 if (ret)
156 return ret;
157
7264354c 158 pc->data->set_enable(chip, pwm, true);
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159
160 return 0;
161}
162
163static void rockchip_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
164{
165 struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
101353c8 166
7264354c 167 pc->data->set_enable(chip, pwm, false);
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168
169 clk_disable(pc->clk);
170}
171
7264354c 172static const struct pwm_ops rockchip_pwm_ops_v1 = {
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173 .config = rockchip_pwm_config,
174 .enable = rockchip_pwm_enable,
175 .disable = rockchip_pwm_disable,
176 .owner = THIS_MODULE,
177};
178
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179static const struct pwm_ops rockchip_pwm_ops_v2 = {
180 .config = rockchip_pwm_config,
181 .set_polarity = rockchip_pwm_set_polarity,
182 .enable = rockchip_pwm_enable,
183 .disable = rockchip_pwm_disable,
184 .owner = THIS_MODULE,
185};
186
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187static const struct rockchip_pwm_data pwm_data_v1 = {
188 .regs = {
189 .duty = 0x04,
190 .period = 0x08,
191 .cntr = 0x00,
192 .ctrl = 0x0c,
193 },
194 .prescaler = 2,
7264354c 195 .ops = &rockchip_pwm_ops_v1,
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196 .set_enable = rockchip_pwm_set_enable_v1,
197};
198
199static const struct rockchip_pwm_data pwm_data_v2 = {
200 .regs = {
201 .duty = 0x08,
202 .period = 0x04,
203 .cntr = 0x00,
204 .ctrl = 0x0c,
205 },
206 .prescaler = 1,
7264354c 207 .ops = &rockchip_pwm_ops_v2,
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208 .set_enable = rockchip_pwm_set_enable_v2,
209};
210
211static const struct rockchip_pwm_data pwm_data_vop = {
212 .regs = {
213 .duty = 0x08,
214 .period = 0x04,
215 .cntr = 0x0c,
216 .ctrl = 0x00,
217 },
218 .prescaler = 1,
7264354c 219 .ops = &rockchip_pwm_ops_v2,
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220 .set_enable = rockchip_pwm_set_enable_v2,
221};
222
223static const struct of_device_id rockchip_pwm_dt_ids[] = {
224 { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
225 { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
226 { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
227 { /* sentinel */ }
228};
229MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
230
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231static int rockchip_pwm_probe(struct platform_device *pdev)
232{
f6306299 233 const struct of_device_id *id;
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234 struct rockchip_pwm_chip *pc;
235 struct resource *r;
236 int ret;
237
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238 id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
239 if (!id)
240 return -EINVAL;
241
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242 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
243 if (!pc)
244 return -ENOMEM;
245
246 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
247 pc->base = devm_ioremap_resource(&pdev->dev, r);
248 if (IS_ERR(pc->base))
249 return PTR_ERR(pc->base);
250
251 pc->clk = devm_clk_get(&pdev->dev, NULL);
252 if (IS_ERR(pc->clk))
253 return PTR_ERR(pc->clk);
254
255 ret = clk_prepare(pc->clk);
256 if (ret)
257 return ret;
258
259 platform_set_drvdata(pdev, pc);
260
f6306299 261 pc->data = id->data;
101353c8 262 pc->chip.dev = &pdev->dev;
7264354c 263 pc->chip.ops = pc->data->ops;
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264 pc->chip.base = -1;
265 pc->chip.npwm = 1;
266
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267 if (pc->data->ops->set_polarity) {
268 pc->chip.of_xlate = of_pwm_xlate_with_flags;
269 pc->chip.of_pwm_n_cells = 3;
270 }
271
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272 ret = pwmchip_add(&pc->chip);
273 if (ret < 0) {
274 clk_unprepare(pc->clk);
275 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
276 }
277
278 return ret;
279}
280
281static int rockchip_pwm_remove(struct platform_device *pdev)
282{
283 struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
284
285 clk_unprepare(pc->clk);
286
287 return pwmchip_remove(&pc->chip);
288}
289
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290static struct platform_driver rockchip_pwm_driver = {
291 .driver = {
292 .name = "rockchip-pwm",
293 .of_match_table = rockchip_pwm_dt_ids,
294 },
295 .probe = rockchip_pwm_probe,
296 .remove = rockchip_pwm_remove,
297};
298module_platform_driver(rockchip_pwm_driver);
299
300MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
301MODULE_DESCRIPTION("Rockchip SoC PWM driver");
302MODULE_LICENSE("GPL v2");