pwm-ab8500.c revision 37b7bf67c36d3a2b426c0cb2787d948949574103 
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/ab8500.h>
12#include <linux/mfd/abx500.h>
13
14/*
15 * PWM Out generators
16 * Bank: 0x10
17 */
18#define AB8500_PWM_OUT_CTRL1_REG	0x60
19#define AB8500_PWM_OUT_CTRL2_REG	0x61
20#define AB8500_PWM_OUT_CTRL7_REG	0x66
21
22/* backlight driver constants */
23#define ENABLE_PWM			1
24#define DISABLE_PWM			0
25
26struct pwm_device {
27	struct device *dev;
28	struct list_head node;
29	const char *label;
30	unsigned int pwm_id;
31};
32
33static LIST_HEAD(pwm_list);
34
35int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
36{
37	int ret = 0;
38	unsigned int higher_val, lower_val;
39	u8 reg;
40
41	/*
42	 * get the first 8 bits that are be written to
43	 * AB8500_PWM_OUT_CTRL1_REG[0:7]
44	 */
45	lower_val = duty_ns & 0x00FF;
46	/*
47	 * get bits [9:10] that are to be written to
48	 * AB8500_PWM_OUT_CTRL2_REG[0:1]
49	 */
50	higher_val = ((duty_ns & 0x0300) >> 8);
51
52	reg = AB8500_PWM_OUT_CTRL1_REG + ((pwm->pwm_id - 1) * 2);
53
54	ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC,
55			reg, (u8)lower_val);
56	if (ret < 0)
57		return ret;
58	ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC,
59			(reg + 1), (u8)higher_val);
60
61	return ret;
62}
63EXPORT_SYMBOL(pwm_config);
64
65int pwm_enable(struct pwm_device *pwm)
66{
67	int ret;
68
69	ret = abx500_mask_and_set_register_interruptible(pwm->dev,
70				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
71				1 << (pwm->pwm_id-1), ENABLE_PWM);
72	if (ret < 0)
73		dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n",
74							pwm->label, ret);
75	return ret;
76}
77EXPORT_SYMBOL(pwm_enable);
78
79void pwm_disable(struct pwm_device *pwm)
80{
81	int ret;
82
83	ret = abx500_mask_and_set_register_interruptible(pwm->dev,
84				AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
85				1 << (pwm->pwm_id-1), DISABLE_PWM);
86	if (ret < 0)
87		dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n",
88							pwm->label, ret);
89	return;
90}
91EXPORT_SYMBOL(pwm_disable);
92
93struct pwm_device *pwm_request(int pwm_id, const char *label)
94{
95	struct pwm_device *pwm;
96
97	list_for_each_entry(pwm, &pwm_list, node) {
98		if (pwm->pwm_id == pwm_id) {
99			pwm->label = label;
100			pwm->pwm_id = pwm_id;
101			return pwm;
102		}
103	}
104
105	return ERR_PTR(-ENOENT);
106}
107EXPORT_SYMBOL(pwm_request);
108
109void pwm_free(struct pwm_device *pwm)
110{
111	pwm_disable(pwm);
112}
113EXPORT_SYMBOL(pwm_free);
114
115static int __devinit ab8500_pwm_probe(struct platform_device *pdev)
116{
117	struct pwm_device *pwm;
118	/*
119	 * Nothing to be done in probe, this is required to get the
120	 * device which is required for ab8500 read and write
121	 */
122	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
123	if (pwm == NULL) {
124		dev_err(&pdev->dev, "failed to allocate memory\n");
125		return -ENOMEM;
126	}
127	pwm->dev = &pdev->dev;
128	pwm->pwm_id = pdev->id;
129	list_add_tail(&pwm->node, &pwm_list);
130	platform_set_drvdata(pdev, pwm);
131	dev_dbg(pwm->dev, "pwm probe successful\n");
132	return 0;
133}
134
135static int __devexit ab8500_pwm_remove(struct platform_device *pdev)
136{
137	struct pwm_device *pwm = platform_get_drvdata(pdev);
138	list_del(&pwm->node);
139	dev_dbg(&pdev->dev, "pwm driver removed\n");
140	kfree(pwm);
141	return 0;
142}
143
144static struct platform_driver ab8500_pwm_driver = {
145	.driver = {
146		.name = "ab8500-pwm",
147		.owner = THIS_MODULE,
148	},
149	.probe = ab8500_pwm_probe,
150	.remove = __devexit_p(ab8500_pwm_remove),
151};
152
153static int __init ab8500_pwm_init(void)
154{
155	return platform_driver_register(&ab8500_pwm_driver);
156}
157
158static void __exit ab8500_pwm_exit(void)
159{
160	platform_driver_unregister(&ab8500_pwm_driver);
161}
162
163subsys_initcall(ab8500_pwm_init);
164module_exit(ab8500_pwm_exit);
165MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
166MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
167MODULE_ALIAS("platform:ab8500-pwm");
168MODULE_LICENSE("GPL v2");
169