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f6b8a570 TR |
1 | /* |
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 | ||
29 | static 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 | ||
40 | struct jz4740_pwm_chip { | |
41 | struct pwm_chip chip; | |
42 | struct clk *clk; | |
43 | }; | |
44 | ||
45 | static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip) | |
46 | { | |
47 | return container_of(chip, struct jz4740_pwm_chip, chip); | |
48 | } | |
49 | ||
50 | static 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 | ||
76 | static 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 | ||
88 | static 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 | ||
99 | static 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 | ||
108 | static 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 | ||
156 | static 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 | ||
3e9fe83d | 165 | static int jz4740_pwm_probe(struct platform_device *pdev) |
f6b8a570 TR |
166 | { |
167 | struct jz4740_pwm_chip *jz4740; | |
f6b8a570 TR |
168 | |
169 | jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL); | |
170 | if (!jz4740) | |
171 | return -ENOMEM; | |
172 | ||
0dc1135f | 173 | jz4740->clk = devm_clk_get(&pdev->dev, "ext"); |
f6b8a570 TR |
174 | if (IS_ERR(jz4740->clk)) |
175 | return PTR_ERR(jz4740->clk); | |
176 | ||
177 | jz4740->chip.dev = &pdev->dev; | |
178 | jz4740->chip.ops = &jz4740_pwm_ops; | |
179 | jz4740->chip.npwm = NUM_PWM; | |
180 | jz4740->chip.base = -1; | |
181 | ||
f6b8a570 TR |
182 | platform_set_drvdata(pdev, jz4740); |
183 | ||
0dc1135f | 184 | return pwmchip_add(&jz4740->chip); |
f6b8a570 TR |
185 | } |
186 | ||
77f37917 | 187 | static int jz4740_pwm_remove(struct platform_device *pdev) |
f6b8a570 TR |
188 | { |
189 | struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev); | |
f6b8a570 | 190 | |
0dc1135f | 191 | return pwmchip_remove(&jz4740->chip); |
f6b8a570 TR |
192 | } |
193 | ||
194 | static struct platform_driver jz4740_pwm_driver = { | |
195 | .driver = { | |
196 | .name = "jz4740-pwm", | |
197 | .owner = THIS_MODULE, | |
198 | }, | |
199 | .probe = jz4740_pwm_probe, | |
fd109112 | 200 | .remove = jz4740_pwm_remove, |
f6b8a570 TR |
201 | }; |
202 | module_platform_driver(jz4740_pwm_driver); | |
203 | ||
204 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); | |
205 | MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver"); | |
206 | MODULE_ALIAS("platform:jz4740-pwm"); | |
207 | MODULE_LICENSE("GPL"); |