pwm-ab8500.c revision ee66e653ca7425bc8ffca4e00f19a8057cd14e4d 
1/*
2 * Copyright (C) ST-Ericsson SA 2010
3 *
4 * Author: Arun R Murthy <arun.murthy@stericsson.com>
5 * License terms: GNU General Public License (GPL) version 2
6 */
7#include <linux/err.h>
8#include <linux/platform_device.h>
9#include <linux/slab.h>
10#include <linux/pwm.h>
11#include <linux/mfd/abx500.h>
12#include <linux/mfd/abx500/ab8500.h>
13#include <linux/module.h>
14
15/*
16 * PWM Out generators
17 * Bank: 0x10
18 */
19#define AB8500_PWM_OUT_CTRL1_REG	0x60
20#define AB8500_PWM_OUT_CTRL2_REG	0x61
21#define AB8500_PWM_OUT_CTRL7_REG	0x66
22
23/* backlight driver constants */
24#define ENABLE_PWM			1
25#define DISABLE_PWM			0
26
27struct pwm_device {
28	struct device *dev;
29	struct list_head node;
30	const char *label;
31	unsigned int pwm_id;
32};
33
34static LIST_HEAD(pwm_list);
35
36int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
37{
38	int ret = 0;
39	unsigned int higher_val, lower_val;
40	u8 reg;
41
42	/*
43	 * get the first 8 bits that are be written to
44	 * AB8500_PWM_OUT_CTRL1_REG[0:7]
45	 */
46	lower_val = duty_ns & 0x00FF;
47	/*
48	 * get bits [9:10] that are to be written to
49	 * AB8500_PWM_OUT_CTRL2_REG[0:1]
50	 */
51	higher_val = ((duty_ns & 0x0300) >> 8);
52
53	reg = AB8500_PWM_OUT_CTRL1_REG + ((pwm->pwm_id - 1) * 2);
54
55	ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC,
56			reg, (u8)lower_val);
57	if (ret < 0)
58		return ret;
59	ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC,
60			(reg + 1), (u8)higher_val);
61
62	return ret;
63}
64EXPORT_SYMBOL(pwm_config);
65
66int pwm_enable(struct pwm_device *pwm)
67{
68	int ret;
69
70	ret = abx500_mask_and_set_register_interruptible(pwm->dev,
71				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
72				1 << (pwm->pwm_id-1), ENABLE_PWM);
73	if (ret < 0)
74		dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n",
75							pwm->label, ret);
76	return ret;
77}
78EXPORT_SYMBOL(pwm_enable);
79
80void pwm_disable(struct pwm_device *pwm)
81{
82	int ret;
83
84	ret = abx500_mask_and_set_register_interruptible(pwm->dev,
85				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
86				1 << (pwm->pwm_id-1), DISABLE_PWM);
87	if (ret < 0)
88		dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n",
89							pwm->label, ret);
90	return;
91}
92EXPORT_SYMBOL(pwm_disable);
93
94struct pwm_device *pwm_request(int pwm_id, const char *label)
95{
96	struct pwm_device *pwm;
97
98	list_for_each_entry(pwm, &pwm_list, node) {
99		if (pwm->pwm_id == pwm_id) {
100			pwm->label = label;
101			pwm->pwm_id = pwm_id;
102			return pwm;
103		}
104	}
105
106	return ERR_PTR(-ENOENT);
107}
108EXPORT_SYMBOL(pwm_request);
109
110void pwm_free(struct pwm_device *pwm)
111{
112	pwm_disable(pwm);
113}
114EXPORT_SYMBOL(pwm_free);
115
116static int __devinit ab8500_pwm_probe(struct platform_device *pdev)
117{
118	struct pwm_device *pwm;
119	/*
120	 * Nothing to be done in probe, this is required to get the
121	 * device which is required for ab8500 read and write
122	 */
123	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
124	if (pwm == NULL) {
125		dev_err(&pdev->dev, "failed to allocate memory\n");
126		return -ENOMEM;
127	}
128	pwm->dev = &pdev->dev;
129	pwm->pwm_id = pdev->id;
130	list_add_tail(&pwm->node, &pwm_list);
131	platform_set_drvdata(pdev, pwm);
132	dev_dbg(pwm->dev, "pwm probe successful\n");
133	return 0;
134}
135
136static int __devexit ab8500_pwm_remove(struct platform_device *pdev)
137{
138	struct pwm_device *pwm = platform_get_drvdata(pdev);
139	list_del(&pwm->node);
140	dev_dbg(&pdev->dev, "pwm driver removed\n");
141	kfree(pwm);
142	return 0;
143}
144
145static struct platform_driver ab8500_pwm_driver = {
146	.driver = {
147		.name = "ab8500-pwm",
148		.owner = THIS_MODULE,
149	},
150	.probe = ab8500_pwm_probe,
151	.remove = __devexit_p(ab8500_pwm_remove),
152};
153
154static int __init ab8500_pwm_init(void)
155{
156	return platform_driver_register(&ab8500_pwm_driver);
157}
158
159static void __exit ab8500_pwm_exit(void)
160{
161	platform_driver_unregister(&ab8500_pwm_driver);
162}
163
164subsys_initcall(ab8500_pwm_init);
165module_exit(ab8500_pwm_exit);
166MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
167MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
168MODULE_ALIAS("platform:ab8500-pwm");
169MODULE_LICENSE("GPL v2");
170