0fcf94ffad321d8bb10911c6cdb65eebd8c8161b
[sfrench/cifs-2.6.git] / drivers / pwm / pwm-rcar.c
1 /*
2  * R-Car PWM Timer driver
3  *
4  * Copyright (C) 2015 Renesas Electronics Corporation
5  *
6  * This is free software; you can redistribute it and/or modify
7  * it under the terms of version 2 of the GNU General Public License as
8  * published by the Free Software Foundation.
9  */
10
11 #include <linux/clk.h>
12 #include <linux/err.h>
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_runtime.h>
18 #include <linux/pwm.h>
19 #include <linux/slab.h>
20
21 #define RCAR_PWM_MAX_DIVISION   24
22 #define RCAR_PWM_MAX_CYCLE      1023
23
24 #define RCAR_PWMCR              0x00
25 #define  RCAR_PWMCR_CC0_MASK    0x000f0000
26 #define  RCAR_PWMCR_CC0_SHIFT   16
27 #define  RCAR_PWMCR_CCMD        BIT(15)
28 #define  RCAR_PWMCR_SYNC        BIT(11)
29 #define  RCAR_PWMCR_SS0         BIT(4)
30 #define  RCAR_PWMCR_EN0         BIT(0)
31
32 #define RCAR_PWMCNT             0x04
33 #define  RCAR_PWMCNT_CYC0_MASK  0x03ff0000
34 #define  RCAR_PWMCNT_CYC0_SHIFT 16
35 #define  RCAR_PWMCNT_PH0_MASK   0x000003ff
36 #define  RCAR_PWMCNT_PH0_SHIFT  0
37
38 struct rcar_pwm_chip {
39         struct pwm_chip chip;
40         void __iomem *base;
41         struct clk *clk;
42 };
43
44 static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
45 {
46         return container_of(chip, struct rcar_pwm_chip, chip);
47 }
48
49 static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
50                            unsigned int offset)
51 {
52         writel(data, rp->base + offset);
53 }
54
55 static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
56 {
57         return readl(rp->base + offset);
58 }
59
60 static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
61                             unsigned int offset)
62 {
63         u32 value;
64
65         value = rcar_pwm_read(rp, offset);
66         value &= ~mask;
67         value |= data & mask;
68         rcar_pwm_write(rp, value, offset);
69 }
70
71 static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
72 {
73         unsigned long clk_rate = clk_get_rate(rp->clk);
74         unsigned long long max; /* max cycle / nanoseconds */
75         unsigned int div;
76
77         if (clk_rate == 0)
78                 return -EINVAL;
79
80         for (div = 0; div <= RCAR_PWM_MAX_DIVISION; div++) {
81                 max = (unsigned long long)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE *
82                         (1 << div);
83                 do_div(max, clk_rate);
84                 if (period_ns <= max)
85                         break;
86         }
87
88         return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
89 }
90
91 static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
92                                        unsigned int div)
93 {
94         u32 value;
95
96         value = rcar_pwm_read(rp, RCAR_PWMCR);
97         value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);
98
99         if (div & 1)
100                 value |= RCAR_PWMCR_CCMD;
101
102         div >>= 1;
103
104         value |= div << RCAR_PWMCR_CC0_SHIFT;
105         rcar_pwm_write(rp, value, RCAR_PWMCR);
106 }
107
108 static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
109                                 int period_ns)
110 {
111         unsigned long long one_cycle, tmp;      /* 0.01 nanoseconds */
112         unsigned long clk_rate = clk_get_rate(rp->clk);
113         u32 cyc, ph;
114
115         one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
116         do_div(one_cycle, clk_rate);
117
118         tmp = period_ns * 100ULL;
119         do_div(tmp, one_cycle);
120         cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
121
122         tmp = duty_ns * 100ULL;
123         do_div(tmp, one_cycle);
124         ph = tmp & RCAR_PWMCNT_PH0_MASK;
125
126         /* Avoid prohibited setting */
127         if (cyc == 0 || ph == 0)
128                 return -EINVAL;
129
130         rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);
131
132         return 0;
133 }
134
135 static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
136 {
137         struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
138
139         return clk_prepare_enable(rp->clk);
140 }
141
142 static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
143 {
144         struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
145
146         clk_disable_unprepare(rp->clk);
147 }
148
149 static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
150                            int duty_ns, int period_ns)
151 {
152         struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
153         int div, ret;
154
155         div = rcar_pwm_get_clock_division(rp, period_ns);
156         if (div < 0)
157                 return div;
158
159         /*
160          * Let the core driver set pwm->period if disabled and duty_ns == 0.
161          * But, this driver should prevent to set the new duty_ns if current
162          * duty_cycle is not set
163          */
164         if (!pwm_is_enabled(pwm) && !duty_ns && !pwm->state.duty_cycle)
165                 return 0;
166
167         rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
168
169         ret = rcar_pwm_set_counter(rp, div, duty_ns, period_ns);
170         if (!ret)
171                 rcar_pwm_set_clock_control(rp, div);
172
173         /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
174         rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
175
176         return ret;
177 }
178
179 static int rcar_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
180 {
181         struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
182         u32 value;
183
184         /* Don't enable the PWM device if CYC0 or PH0 is 0 */
185         value = rcar_pwm_read(rp, RCAR_PWMCNT);
186         if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
187             (value & RCAR_PWMCNT_PH0_MASK) == 0)
188                 return -EINVAL;
189
190         rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);
191
192         return 0;
193 }
194
195 static void rcar_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
196 {
197         struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
198
199         rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
200 }
201
202 static const struct pwm_ops rcar_pwm_ops = {
203         .request = rcar_pwm_request,
204         .free = rcar_pwm_free,
205         .config = rcar_pwm_config,
206         .enable = rcar_pwm_enable,
207         .disable = rcar_pwm_disable,
208         .owner = THIS_MODULE,
209 };
210
211 static int rcar_pwm_probe(struct platform_device *pdev)
212 {
213         struct rcar_pwm_chip *rcar_pwm;
214         struct resource *res;
215         int ret;
216
217         rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL);
218         if (rcar_pwm == NULL)
219                 return -ENOMEM;
220
221         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
222         rcar_pwm->base = devm_ioremap_resource(&pdev->dev, res);
223         if (IS_ERR(rcar_pwm->base))
224                 return PTR_ERR(rcar_pwm->base);
225
226         rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
227         if (IS_ERR(rcar_pwm->clk)) {
228                 dev_err(&pdev->dev, "cannot get clock\n");
229                 return PTR_ERR(rcar_pwm->clk);
230         }
231
232         platform_set_drvdata(pdev, rcar_pwm);
233
234         rcar_pwm->chip.dev = &pdev->dev;
235         rcar_pwm->chip.ops = &rcar_pwm_ops;
236         rcar_pwm->chip.base = -1;
237         rcar_pwm->chip.npwm = 1;
238
239         ret = pwmchip_add(&rcar_pwm->chip);
240         if (ret < 0) {
241                 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret);
242                 return ret;
243         }
244
245         pm_runtime_enable(&pdev->dev);
246
247         return 0;
248 }
249
250 static int rcar_pwm_remove(struct platform_device *pdev)
251 {
252         struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
253
254         pm_runtime_disable(&pdev->dev);
255
256         return pwmchip_remove(&rcar_pwm->chip);
257 }
258
259 static const struct of_device_id rcar_pwm_of_table[] = {
260         { .compatible = "renesas,pwm-rcar", },
261         { },
262 };
263 MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
264
265 static struct platform_driver rcar_pwm_driver = {
266         .probe = rcar_pwm_probe,
267         .remove = rcar_pwm_remove,
268         .driver = {
269                 .name = "pwm-rcar",
270                 .of_match_table = of_match_ptr(rcar_pwm_of_table),
271         }
272 };
273 module_platform_driver(rcar_pwm_driver);
274
275 MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
276 MODULE_DESCRIPTION("Renesas PWM Timer Driver");
277 MODULE_LICENSE("GPL v2");
278 MODULE_ALIAS("platform:pwm-rcar");