treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / pwm / pwm-ep93xx.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PWM framework driver for Cirrus Logic EP93xx
4  *
5  * Copyright (c) 2009        Matthieu Crapet <mcrapet@gmail.com>
6  * Copyright (c) 2009, 2013  H Hartley Sweeten <hsweeten@visionengravers.com>
7  *
8  * EP9301/02 have only one channel:
9  *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
10  *
11  * EP9307 has only one channel:
12  *   platform device ep93xx-pwm.0 - PWMOUT
13  *
14  * EP9312/15 have two channels:
15  *   platform device ep93xx-pwm.0 - PWMOUT
16  *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
17  */
18
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/slab.h>
22 #include <linux/clk.h>
23 #include <linux/err.h>
24 #include <linux/io.h>
25 #include <linux/pwm.h>
26
27 #include <asm/div64.h>
28
29 #include <linux/soc/cirrus/ep93xx.h>    /* for ep93xx_pwm_{acquire,release}_gpio() */
30
31 #define EP93XX_PWMx_TERM_COUNT  0x00
32 #define EP93XX_PWMx_DUTY_CYCLE  0x04
33 #define EP93XX_PWMx_ENABLE      0x08
34 #define EP93XX_PWMx_INVERT      0x0c
35
36 struct ep93xx_pwm {
37         void __iomem *base;
38         struct clk *clk;
39         struct pwm_chip chip;
40 };
41
42 static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
43 {
44         return container_of(chip, struct ep93xx_pwm, chip);
45 }
46
47 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
48 {
49         struct platform_device *pdev = to_platform_device(chip->dev);
50
51         return ep93xx_pwm_acquire_gpio(pdev);
52 }
53
54 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
55 {
56         struct platform_device *pdev = to_platform_device(chip->dev);
57
58         ep93xx_pwm_release_gpio(pdev);
59 }
60
61 static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
62                              int duty_ns, int period_ns)
63 {
64         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
65         void __iomem *base = ep93xx_pwm->base;
66         unsigned long long c;
67         unsigned long period_cycles;
68         unsigned long duty_cycles;
69         unsigned long term;
70         int ret = 0;
71
72         /*
73          * The clock needs to be enabled to access the PWM registers.
74          * Configuration can be changed at any time.
75          */
76         if (!pwm_is_enabled(pwm)) {
77                 ret = clk_enable(ep93xx_pwm->clk);
78                 if (ret)
79                         return ret;
80         }
81
82         c = clk_get_rate(ep93xx_pwm->clk);
83         c *= period_ns;
84         do_div(c, 1000000000);
85         period_cycles = c;
86
87         c = period_cycles;
88         c *= duty_ns;
89         do_div(c, period_ns);
90         duty_cycles = c;
91
92         if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
93                 term = readw(base + EP93XX_PWMx_TERM_COUNT);
94
95                 /* Order is important if PWM is running */
96                 if (period_cycles > term) {
97                         writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
98                         writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
99                 } else {
100                         writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
101                         writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
102                 }
103         } else {
104                 ret = -EINVAL;
105         }
106
107         if (!pwm_is_enabled(pwm))
108                 clk_disable(ep93xx_pwm->clk);
109
110         return ret;
111 }
112
113 static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
114                                enum pwm_polarity polarity)
115 {
116         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
117         int ret;
118
119         /*
120          * The clock needs to be enabled to access the PWM registers.
121          * Polarity can only be changed when the PWM is disabled.
122          */
123         ret = clk_enable(ep93xx_pwm->clk);
124         if (ret)
125                 return ret;
126
127         if (polarity == PWM_POLARITY_INVERSED)
128                 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
129         else
130                 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
131
132         clk_disable(ep93xx_pwm->clk);
133
134         return 0;
135 }
136
137 static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
138 {
139         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
140         int ret;
141
142         ret = clk_enable(ep93xx_pwm->clk);
143         if (ret)
144                 return ret;
145
146         writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
147
148         return 0;
149 }
150
151 static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
152 {
153         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
154
155         writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
156         clk_disable(ep93xx_pwm->clk);
157 }
158
159 static const struct pwm_ops ep93xx_pwm_ops = {
160         .request = ep93xx_pwm_request,
161         .free = ep93xx_pwm_free,
162         .config = ep93xx_pwm_config,
163         .set_polarity = ep93xx_pwm_polarity,
164         .enable = ep93xx_pwm_enable,
165         .disable = ep93xx_pwm_disable,
166         .owner = THIS_MODULE,
167 };
168
169 static int ep93xx_pwm_probe(struct platform_device *pdev)
170 {
171         struct ep93xx_pwm *ep93xx_pwm;
172         struct resource *res;
173         int ret;
174
175         ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL);
176         if (!ep93xx_pwm)
177                 return -ENOMEM;
178
179         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
180         ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res);
181         if (IS_ERR(ep93xx_pwm->base))
182                 return PTR_ERR(ep93xx_pwm->base);
183
184         ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
185         if (IS_ERR(ep93xx_pwm->clk))
186                 return PTR_ERR(ep93xx_pwm->clk);
187
188         ep93xx_pwm->chip.dev = &pdev->dev;
189         ep93xx_pwm->chip.ops = &ep93xx_pwm_ops;
190         ep93xx_pwm->chip.base = -1;
191         ep93xx_pwm->chip.npwm = 1;
192
193         ret = pwmchip_add(&ep93xx_pwm->chip);
194         if (ret < 0)
195                 return ret;
196
197         platform_set_drvdata(pdev, ep93xx_pwm);
198         return 0;
199 }
200
201 static int ep93xx_pwm_remove(struct platform_device *pdev)
202 {
203         struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev);
204
205         return pwmchip_remove(&ep93xx_pwm->chip);
206 }
207
208 static struct platform_driver ep93xx_pwm_driver = {
209         .driver = {
210                 .name = "ep93xx-pwm",
211         },
212         .probe = ep93xx_pwm_probe,
213         .remove = ep93xx_pwm_remove,
214 };
215 module_platform_driver(ep93xx_pwm_driver);
216
217 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
218 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");
219 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
220 MODULE_ALIAS("platform:ep93xx-pwm");
221 MODULE_LICENSE("GPL");