Merge tag 'v5.9-rc2' into asoc-5.9
[linux-2.6-microblaze.git] / drivers / pwm / pwm-bcm-iproc.c
1 /*
2  * Copyright (C) 2016 Broadcom
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation version 2.
7  *
8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
9  * kind, whether express or implied; without even the implied warranty
10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13
14 #include <linux/clk.h>
15 #include <linux/delay.h>
16 #include <linux/err.h>
17 #include <linux/io.h>
18 #include <linux/math64.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/pwm.h>
23
24 #define IPROC_PWM_CTRL_OFFSET                   0x00
25 #define IPROC_PWM_CTRL_TYPE_SHIFT(ch)           (15 + (ch))
26 #define IPROC_PWM_CTRL_POLARITY_SHIFT(ch)       (8 + (ch))
27 #define IPROC_PWM_CTRL_EN_SHIFT(ch)             (ch)
28
29 #define IPROC_PWM_PERIOD_OFFSET(ch)             (0x04 + ((ch) << 3))
30 #define IPROC_PWM_PERIOD_MIN                    0x02
31 #define IPROC_PWM_PERIOD_MAX                    0xffff
32
33 #define IPROC_PWM_DUTY_CYCLE_OFFSET(ch)         (0x08 + ((ch) << 3))
34 #define IPROC_PWM_DUTY_CYCLE_MIN                0x00
35 #define IPROC_PWM_DUTY_CYCLE_MAX                0xffff
36
37 #define IPROC_PWM_PRESCALE_OFFSET               0x24
38 #define IPROC_PWM_PRESCALE_BITS                 0x06
39 #define IPROC_PWM_PRESCALE_SHIFT(ch)            ((3 - (ch)) * \
40                                                  IPROC_PWM_PRESCALE_BITS)
41 #define IPROC_PWM_PRESCALE_MASK(ch)             (IPROC_PWM_PRESCALE_MAX << \
42                                                  IPROC_PWM_PRESCALE_SHIFT(ch))
43 #define IPROC_PWM_PRESCALE_MIN                  0x00
44 #define IPROC_PWM_PRESCALE_MAX                  0x3f
45
46 struct iproc_pwmc {
47         struct pwm_chip chip;
48         void __iomem *base;
49         struct clk *clk;
50 };
51
52 static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *chip)
53 {
54         return container_of(chip, struct iproc_pwmc, chip);
55 }
56
57 static void iproc_pwmc_enable(struct iproc_pwmc *ip, unsigned int channel)
58 {
59         u32 value;
60
61         value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
62         value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(channel);
63         writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
64
65         /* must be a 400 ns delay between clearing and setting enable bit */
66         ndelay(400);
67 }
68
69 static void iproc_pwmc_disable(struct iproc_pwmc *ip, unsigned int channel)
70 {
71         u32 value;
72
73         value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
74         value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(channel));
75         writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
76
77         /* must be a 400 ns delay between clearing and setting enable bit */
78         ndelay(400);
79 }
80
81 static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
82                                  struct pwm_state *state)
83 {
84         struct iproc_pwmc *ip = to_iproc_pwmc(chip);
85         u64 tmp, multi, rate;
86         u32 value, prescale;
87
88         value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
89
90         if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))
91                 state->enabled = true;
92         else
93                 state->enabled = false;
94
95         if (value & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm)))
96                 state->polarity = PWM_POLARITY_NORMAL;
97         else
98                 state->polarity = PWM_POLARITY_INVERSED;
99
100         rate = clk_get_rate(ip->clk);
101         if (rate == 0) {
102                 state->period = 0;
103                 state->duty_cycle = 0;
104                 return;
105         }
106
107         value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
108         prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
109         prescale &= IPROC_PWM_PRESCALE_MAX;
110
111         multi = NSEC_PER_SEC * (prescale + 1);
112
113         value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
114         tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
115         state->period = div64_u64(tmp, rate);
116
117         value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
118         tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
119         state->duty_cycle = div64_u64(tmp, rate);
120 }
121
122 static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
123                             const struct pwm_state *state)
124 {
125         unsigned long prescale = IPROC_PWM_PRESCALE_MIN;
126         struct iproc_pwmc *ip = to_iproc_pwmc(chip);
127         u32 value, period, duty;
128         u64 rate;
129
130         rate = clk_get_rate(ip->clk);
131
132         /*
133          * Find period count, duty count and prescale to suit duty_cycle and
134          * period. This is done according to formulas described below:
135          *
136          * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE
137          * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
138          *
139          * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
140          * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
141          */
142         while (1) {
143                 u64 value, div;
144
145                 div = NSEC_PER_SEC * (prescale + 1);
146                 value = rate * state->period;
147                 period = div64_u64(value, div);
148                 value = rate * state->duty_cycle;
149                 duty = div64_u64(value, div);
150
151                 if (period < IPROC_PWM_PERIOD_MIN)
152                         return -EINVAL;
153
154                 if (period <= IPROC_PWM_PERIOD_MAX &&
155                      duty <= IPROC_PWM_DUTY_CYCLE_MAX)
156                         break;
157
158                 /* Otherwise, increase prescale and recalculate counts */
159                 if (++prescale > IPROC_PWM_PRESCALE_MAX)
160                         return -EINVAL;
161         }
162
163         iproc_pwmc_disable(ip, pwm->hwpwm);
164
165         /* Set prescale */
166         value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
167         value &= ~IPROC_PWM_PRESCALE_MASK(pwm->hwpwm);
168         value |= prescale << IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
169         writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);
170
171         /* set period and duty cycle */
172         writel(period, ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
173         writel(duty, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
174
175         /* set polarity */
176         value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
177
178         if (state->polarity == PWM_POLARITY_NORMAL)
179                 value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm);
180         else
181                 value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm));
182
183         writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
184
185         if (state->enabled)
186                 iproc_pwmc_enable(ip, pwm->hwpwm);
187
188         return 0;
189 }
190
191 static const struct pwm_ops iproc_pwm_ops = {
192         .apply = iproc_pwmc_apply,
193         .get_state = iproc_pwmc_get_state,
194         .owner = THIS_MODULE,
195 };
196
197 static int iproc_pwmc_probe(struct platform_device *pdev)
198 {
199         struct iproc_pwmc *ip;
200         struct resource *res;
201         unsigned int i;
202         u32 value;
203         int ret;
204
205         ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL);
206         if (!ip)
207                 return -ENOMEM;
208
209         platform_set_drvdata(pdev, ip);
210
211         ip->chip.dev = &pdev->dev;
212         ip->chip.ops = &iproc_pwm_ops;
213         ip->chip.base = -1;
214         ip->chip.npwm = 4;
215         ip->chip.of_xlate = of_pwm_xlate_with_flags;
216         ip->chip.of_pwm_n_cells = 3;
217
218         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
219         ip->base = devm_ioremap_resource(&pdev->dev, res);
220         if (IS_ERR(ip->base))
221                 return PTR_ERR(ip->base);
222
223         ip->clk = devm_clk_get(&pdev->dev, NULL);
224         if (IS_ERR(ip->clk)) {
225                 dev_err(&pdev->dev, "failed to get clock: %ld\n",
226                         PTR_ERR(ip->clk));
227                 return PTR_ERR(ip->clk);
228         }
229
230         ret = clk_prepare_enable(ip->clk);
231         if (ret < 0) {
232                 dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
233                 return ret;
234         }
235
236         /* Set full drive and normal polarity for all channels */
237         value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
238
239         for (i = 0; i < ip->chip.npwm; i++) {
240                 value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(i));
241                 value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(i);
242         }
243
244         writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
245
246         ret = pwmchip_add(&ip->chip);
247         if (ret < 0) {
248                 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
249                 clk_disable_unprepare(ip->clk);
250         }
251
252         return ret;
253 }
254
255 static int iproc_pwmc_remove(struct platform_device *pdev)
256 {
257         struct iproc_pwmc *ip = platform_get_drvdata(pdev);
258
259         clk_disable_unprepare(ip->clk);
260
261         return pwmchip_remove(&ip->chip);
262 }
263
264 static const struct of_device_id bcm_iproc_pwmc_dt[] = {
265         { .compatible = "brcm,iproc-pwm" },
266         { },
267 };
268 MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);
269
270 static struct platform_driver iproc_pwmc_driver = {
271         .driver = {
272                 .name = "bcm-iproc-pwm",
273                 .of_match_table = bcm_iproc_pwmc_dt,
274         },
275         .probe = iproc_pwmc_probe,
276         .remove = iproc_pwmc_remove,
277 };
278 module_platform_driver(iproc_pwmc_driver);
279
280 MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>");
281 MODULE_DESCRIPTION("Broadcom iProc PWM driver");
282 MODULE_LICENSE("GPL v2");