[go: nahoru, domu]
1/*
2 * Blackfin Pulse Width Modulation (PWM) core
3 *
4 * Copyright (c) 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 */
8
9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/pwm.h>
12#include <linux/slab.h>
13
14#include <asm/gptimers.h>
15#include <asm/portmux.h>
16
17struct bfin_pwm_chip {
18	struct pwm_chip chip;
19};
20
21struct bfin_pwm {
22	unsigned short pin;
23};
24
25static const unsigned short pwm_to_gptimer_per[] = {
26	P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
27	P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
28};
29
30static int bfin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
31{
32	struct bfin_pwm *priv;
33	int ret;
34
35	if (pwm->hwpwm >= ARRAY_SIZE(pwm_to_gptimer_per))
36		return -EINVAL;
37
38	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
39	if (!priv)
40		return -ENOMEM;
41
42	priv->pin = pwm_to_gptimer_per[pwm->hwpwm];
43
44	ret = peripheral_request(priv->pin, NULL);
45	if (ret) {
46		kfree(priv);
47		return ret;
48	}
49
50	pwm_set_chip_data(pwm, priv);
51
52	return 0;
53}
54
55static void bfin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
56{
57	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
58
59	if (priv) {
60		peripheral_free(priv->pin);
61		kfree(priv);
62	}
63}
64
65static int bfin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
66		int duty_ns, int period_ns)
67{
68	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
69	unsigned long period, duty;
70	unsigned long long val;
71
72	val = (unsigned long long)get_sclk() * period_ns;
73	do_div(val, NSEC_PER_SEC);
74	period = val;
75
76	val = (unsigned long long)period * duty_ns;
77	do_div(val, period_ns);
78	duty = period - val;
79
80	if (duty >= period)
81		duty = period - 1;
82
83	set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
84	set_gptimer_pwidth(priv->pin, duty);
85	set_gptimer_period(priv->pin, period);
86
87	return 0;
88}
89
90static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
91{
92	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
93
94	enable_gptimer(priv->pin);
95
96	return 0;
97}
98
99static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
100{
101	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
102
103	disable_gptimer(priv->pin);
104}
105
106static struct pwm_ops bfin_pwm_ops = {
107	.request = bfin_pwm_request,
108	.free = bfin_pwm_free,
109	.config = bfin_pwm_config,
110	.enable = bfin_pwm_enable,
111	.disable = bfin_pwm_disable,
112	.owner = THIS_MODULE,
113};
114
115static int bfin_pwm_probe(struct platform_device *pdev)
116{
117	struct bfin_pwm_chip *pwm;
118	int ret;
119
120	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
121	if (!pwm) {
122		dev_err(&pdev->dev, "failed to allocate memory\n");
123		return -ENOMEM;
124	}
125
126	platform_set_drvdata(pdev, pwm);
127
128	pwm->chip.dev = &pdev->dev;
129	pwm->chip.ops = &bfin_pwm_ops;
130	pwm->chip.base = -1;
131	pwm->chip.npwm = 12;
132
133	ret = pwmchip_add(&pwm->chip);
134	if (ret < 0) {
135		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
136		return ret;
137	}
138
139	return 0;
140}
141
142static int bfin_pwm_remove(struct platform_device *pdev)
143{
144	struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev);
145
146	return pwmchip_remove(&pwm->chip);
147}
148
149static struct platform_driver bfin_pwm_driver = {
150	.driver = {
151		.name = "bfin-pwm",
152		.owner = THIS_MODULE,
153	},
154	.probe = bfin_pwm_probe,
155	.remove = bfin_pwm_remove,
156};
157
158module_platform_driver(bfin_pwm_driver);
159
160MODULE_LICENSE("GPL");
161