tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * R-Car PWM Timer driver
4 *
5 * Copyright (C) 2015 Renesas Electronics Corporation
6 */
7
8#include <linux/clk.h>
9#include <linux/err.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/pm_runtime.h>
15#include <linux/pwm.h>
16#include <linux/slab.h>
17
18#define RCAR_PWM_MAX_DIVISION 24
19#define RCAR_PWM_MAX_CYCLE 1023
20
21#define RCAR_PWMCR 0x00
22#define RCAR_PWMCR_CC0_MASK 0x000f0000
23#define RCAR_PWMCR_CC0_SHIFT 16
24#define RCAR_PWMCR_CCMD BIT(15)
25#define RCAR_PWMCR_SYNC BIT(11)
26#define RCAR_PWMCR_SS0 BIT(4)
27#define RCAR_PWMCR_EN0 BIT(0)
28
29#define RCAR_PWMCNT 0x04
30#define RCAR_PWMCNT_CYC0_MASK 0x03ff0000
31#define RCAR_PWMCNT_CYC0_SHIFT 16
32#define RCAR_PWMCNT_PH0_MASK 0x000003ff
33#define RCAR_PWMCNT_PH0_SHIFT 0
34
35struct rcar_pwm_chip {
36 struct pwm_chip chip;
37 void __iomem *base;
38 struct clk *clk;
39};
40
41static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
42{
43 return container_of(chip, struct rcar_pwm_chip, chip);
44}
45
46static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
47 unsigned int offset)
48{
49 writel(data, rp->base + offset);
50}
51
52static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
53{
54 return readl(rp->base + offset);
55}
56
57static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
58 unsigned int offset)
59{
60 u32 value;
61
62 value = rcar_pwm_read(rp, offset);
63 value &= ~mask;
64 value |= data & mask;
65 rcar_pwm_write(rp, value, offset);
66}
67
68static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
69{
70 unsigned long clk_rate = clk_get_rate(rp->clk);
71 unsigned long long max; /* max cycle / nanoseconds */
72 unsigned int div;
73
74 if (clk_rate == 0)
75 return -EINVAL;
76
77 for (div = 0; div <= RCAR_PWM_MAX_DIVISION; div++) {
78 max = (unsigned long long)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE *
79 (1 << div);
80 do_div(max, clk_rate);
81 if (period_ns <= max)
82 break;
83 }
84
85 return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
86}
87
88static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
89 unsigned int div)
90{
91 u32 value;
92
93 value = rcar_pwm_read(rp, RCAR_PWMCR);
94 value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);
95
96 if (div & 1)
97 value |= RCAR_PWMCR_CCMD;
98
99 div >>= 1;
100
101 value |= div << RCAR_PWMCR_CC0_SHIFT;
102 rcar_pwm_write(rp, value, RCAR_PWMCR);
103}
104
105static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
106 int period_ns)
107{
108 unsigned long long one_cycle, tmp; /* 0.01 nanoseconds */
109 unsigned long clk_rate = clk_get_rate(rp->clk);
110 u32 cyc, ph;
111
112 one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
113 do_div(one_cycle, clk_rate);
114
115 tmp = period_ns * 100ULL;
116 do_div(tmp, one_cycle);
117 cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
118
119 tmp = duty_ns * 100ULL;
120 do_div(tmp, one_cycle);
121 ph = tmp & RCAR_PWMCNT_PH0_MASK;
122
123 /* Avoid prohibited setting */
124 if (cyc == 0 || ph == 0)
125 return -EINVAL;
126
127 rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);
128
129 return 0;
130}
131
132static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
133{
134 return pm_runtime_get_sync(chip->dev);
135}
136
137static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
138{
139 pm_runtime_put(chip->dev);
140}
141
142static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
143 int duty_ns, int period_ns)
144{
145 struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
146 int div, ret;
147
148 div = rcar_pwm_get_clock_division(rp, period_ns);
149 if (div < 0)
150 return div;
151
152 /*
153 * Let the core driver set pwm->period if disabled and duty_ns == 0.
154 * But, this driver should prevent to set the new duty_ns if current
155 * duty_cycle is not set
156 */
157 if (!pwm_is_enabled(pwm) && !duty_ns && !pwm->state.duty_cycle)
158 return 0;
159
160 rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
161
162 ret = rcar_pwm_set_counter(rp, div, duty_ns, period_ns);
163 if (!ret)
164 rcar_pwm_set_clock_control(rp, div);
165
166 /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
167 rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
168
169 return ret;
170}
171
172static int rcar_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
173{
174 struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
175 u32 value;
176
177 /* Don't enable the PWM device if CYC0 or PH0 is 0 */
178 value = rcar_pwm_read(rp, RCAR_PWMCNT);
179 if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
180 (value & RCAR_PWMCNT_PH0_MASK) == 0)
181 return -EINVAL;
182
183 rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);
184
185 return 0;
186}
187
188static void rcar_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
189{
190 struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
191
192 rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
193}
194
195static const struct pwm_ops rcar_pwm_ops = {
196 .request = rcar_pwm_request,
197 .free = rcar_pwm_free,
198 .config = rcar_pwm_config,
199 .enable = rcar_pwm_enable,
200 .disable = rcar_pwm_disable,
201 .owner = THIS_MODULE,
202};
203
204static int rcar_pwm_probe(struct platform_device *pdev)
205{
206 struct rcar_pwm_chip *rcar_pwm;
207 struct resource *res;
208 int ret;
209
210 rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL);
211 if (rcar_pwm == NULL)
212 return -ENOMEM;
213
214 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
215 rcar_pwm->base = devm_ioremap_resource(&pdev->dev, res);
216 if (IS_ERR(rcar_pwm->base))
217 return PTR_ERR(rcar_pwm->base);
218
219 rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
220 if (IS_ERR(rcar_pwm->clk)) {
221 dev_err(&pdev->dev, "cannot get clock\n");
222 return PTR_ERR(rcar_pwm->clk);
223 }
224
225 platform_set_drvdata(pdev, rcar_pwm);
226
227 rcar_pwm->chip.dev = &pdev->dev;
228 rcar_pwm->chip.ops = &rcar_pwm_ops;
229 rcar_pwm->chip.base = -1;
230 rcar_pwm->chip.npwm = 1;
231
232 ret = pwmchip_add(&rcar_pwm->chip);
233 if (ret < 0) {
234 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret);
235 return ret;
236 }
237
238 pm_runtime_enable(&pdev->dev);
239
240 return 0;
241}
242
243static int rcar_pwm_remove(struct platform_device *pdev)
244{
245 struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
246
247 pm_runtime_disable(&pdev->dev);
248
249 return pwmchip_remove(&rcar_pwm->chip);
250}
251
252static const struct of_device_id rcar_pwm_of_table[] = {
253 { .compatible = "renesas,pwm-rcar", },
254 { },
255};
256MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
257
258#ifdef CONFIG_PM_SLEEP
259static struct pwm_device *rcar_pwm_dev_to_pwm_dev(struct device *dev)
260{
261 struct rcar_pwm_chip *rcar_pwm = dev_get_drvdata(dev);
262 struct pwm_chip *chip = &rcar_pwm->chip;
263
264 return &chip->pwms[0];
265}
266
267static int rcar_pwm_suspend(struct device *dev)
268{
269 struct pwm_device *pwm = rcar_pwm_dev_to_pwm_dev(dev);
270
271 if (!test_bit(PWMF_REQUESTED, &pwm->flags))
272 return 0;
273
274 pm_runtime_put(dev);
275
276 return 0;
277}
278
279static int rcar_pwm_resume(struct device *dev)
280{
281 struct pwm_device *pwm = rcar_pwm_dev_to_pwm_dev(dev);
282
283 if (!test_bit(PWMF_REQUESTED, &pwm->flags))
284 return 0;
285
286 pm_runtime_get_sync(dev);
287
288 rcar_pwm_config(pwm->chip, pwm, pwm->state.duty_cycle,
289 pwm->state.period);
290 if (pwm_is_enabled(pwm))
291 rcar_pwm_enable(pwm->chip, pwm);
292
293 return 0;
294}
295#endif /* CONFIG_PM_SLEEP */
296static SIMPLE_DEV_PM_OPS(rcar_pwm_pm_ops, rcar_pwm_suspend, rcar_pwm_resume);
297
298static struct platform_driver rcar_pwm_driver = {
299 .probe = rcar_pwm_probe,
300 .remove = rcar_pwm_remove,
301 .driver = {
302 .name = "pwm-rcar",
303 .pm = &rcar_pwm_pm_ops,
304 .of_match_table = of_match_ptr(rcar_pwm_of_table),
305 }
306};
307module_platform_driver(rcar_pwm_driver);
308
309MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
310MODULE_DESCRIPTION("Renesas PWM Timer Driver");
311MODULE_LICENSE("GPL v2");
312MODULE_ALIAS("platform:pwm-rcar");