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Thierry Redingf6b8a572012-08-22 10:01:24 +02001/*
2 * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
3 * JZ4740 platform PWM support
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 *
10 * You should have received a copy of the GNU General Public License along
11 * with this program; if not, write to the Free Software Foundation, Inc.,
12 * 675 Mass Ave, Cambridge, MA 02139, USA.
13 *
14 */
15
16#include <linux/clk.h>
17#include <linux/err.h>
18#include <linux/gpio.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/platform_device.h>
22#include <linux/pwm.h>
23
24#include <asm/mach-jz4740/gpio.h>
25#include <asm/mach-jz4740/timer.h>
26
27#define NUM_PWM 8
28
29static const unsigned int jz4740_pwm_gpio_list[NUM_PWM] = {
30 JZ_GPIO_PWM0,
31 JZ_GPIO_PWM1,
32 JZ_GPIO_PWM2,
33 JZ_GPIO_PWM3,
34 JZ_GPIO_PWM4,
35 JZ_GPIO_PWM5,
36 JZ_GPIO_PWM6,
37 JZ_GPIO_PWM7,
38};
39
40struct jz4740_pwm_chip {
41 struct pwm_chip chip;
42 struct clk *clk;
43};
44
45static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
46{
47 return container_of(chip, struct jz4740_pwm_chip, chip);
48}
49
50static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
51{
52 unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm];
53 int ret;
54
55 /*
56 * Timers 0 and 1 are used for system tasks, so they are unavailable
57 * for use as PWMs.
58 */
59 if (pwm->hwpwm < 2)
60 return -EBUSY;
61
62 ret = gpio_request(gpio, pwm->label);
63 if (ret) {
64 dev_err(chip->dev, "Failed to request GPIO#%u for PWM: %d\n",
65 gpio, ret);
66 return ret;
67 }
68
69 jz_gpio_set_function(gpio, JZ_GPIO_FUNC_PWM);
70
71 jz4740_timer_start(pwm->hwpwm);
72
73 return 0;
74}
75
76static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
77{
78 unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm];
79
80 jz4740_timer_set_ctrl(pwm->hwpwm, 0);
81
82 jz_gpio_set_function(gpio, JZ_GPIO_FUNC_NONE);
83 gpio_free(gpio);
84
85 jz4740_timer_stop(pwm->hwpwm);
86}
87
88static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
89{
90 uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
91
92 ctrl |= JZ_TIMER_CTRL_PWM_ENABLE;
93 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
94 jz4740_timer_enable(pwm->hwpwm);
95
96 return 0;
97}
98
99static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
100{
101 uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
102
103 ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE;
104 jz4740_timer_disable(pwm->hwpwm);
105 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
106}
107
108static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
109 int duty_ns, int period_ns)
110{
111 struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
112 unsigned long long tmp;
113 unsigned long period, duty;
114 unsigned int prescaler = 0;
115 uint16_t ctrl;
116 bool is_enabled;
117
118 tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns;
119 do_div(tmp, 1000000000);
120 period = tmp;
121
122 while (period > 0xffff && prescaler < 6) {
123 period >>= 2;
124 ++prescaler;
125 }
126
127 if (prescaler == 6)
128 return -EINVAL;
129
130 tmp = (unsigned long long)period * duty_ns;
131 do_div(tmp, period_ns);
132 duty = period - tmp;
133
134 if (duty >= period)
135 duty = period - 1;
136
137 is_enabled = jz4740_timer_is_enabled(pwm->hwpwm);
138 if (is_enabled)
139 jz4740_pwm_disable(chip, pwm);
140
141 jz4740_timer_set_count(pwm->hwpwm, 0);
142 jz4740_timer_set_duty(pwm->hwpwm, duty);
143 jz4740_timer_set_period(pwm->hwpwm, period);
144
145 ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
146 JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
147
148 jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
149
150 if (is_enabled)
151 jz4740_pwm_enable(chip, pwm);
152
153 return 0;
154}
155
156static const struct pwm_ops jz4740_pwm_ops = {
157 .request = jz4740_pwm_request,
158 .free = jz4740_pwm_free,
159 .config = jz4740_pwm_config,
160 .enable = jz4740_pwm_enable,
161 .disable = jz4740_pwm_disable,
162 .owner = THIS_MODULE,
163};
164
Bill Pemberton3e9fe832012-11-19 13:23:14 -0500165static int jz4740_pwm_probe(struct platform_device *pdev)
Thierry Redingf6b8a572012-08-22 10:01:24 +0200166{
167 struct jz4740_pwm_chip *jz4740;
168 int ret;
169
170 jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL);
171 if (!jz4740)
172 return -ENOMEM;
173
174 jz4740->clk = clk_get(NULL, "ext");
175 if (IS_ERR(jz4740->clk))
176 return PTR_ERR(jz4740->clk);
177
178 jz4740->chip.dev = &pdev->dev;
179 jz4740->chip.ops = &jz4740_pwm_ops;
180 jz4740->chip.npwm = NUM_PWM;
181 jz4740->chip.base = -1;
182
183 ret = pwmchip_add(&jz4740->chip);
184 if (ret < 0) {
185 clk_put(jz4740->clk);
186 return ret;
187 }
188
189 platform_set_drvdata(pdev, jz4740);
190
191 return 0;
192}
193
Bill Pemberton77f37912012-11-19 13:26:09 -0500194static int jz4740_pwm_remove(struct platform_device *pdev)
Thierry Redingf6b8a572012-08-22 10:01:24 +0200195{
196 struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
197 int ret;
198
199 ret = pwmchip_remove(&jz4740->chip);
200 if (ret < 0)
201 return ret;
202
203 clk_put(jz4740->clk);
204
205 return 0;
206}
207
208static struct platform_driver jz4740_pwm_driver = {
209 .driver = {
210 .name = "jz4740-pwm",
211 .owner = THIS_MODULE,
212 },
213 .probe = jz4740_pwm_probe,
Bill Pembertonfd109112012-11-19 13:21:28 -0500214 .remove = jz4740_pwm_remove,
Thierry Redingf6b8a572012-08-22 10:01:24 +0200215};
216module_platform_driver(jz4740_pwm_driver);
217
218MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
219MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
220MODULE_ALIAS("platform:jz4740-pwm");
221MODULE_LICENSE("GPL");