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
26 struct pwm_device {
27 struct device *dev;
28 struct list_head node;
29 const char *label;
30 unsigned int pwm_id;
31 };
32
33 static LIST_HEAD(pwm_list);
34
pwm_config(struct pwm_device * pwm,int duty_ns,int period_ns)35 int 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 }
63 EXPORT_SYMBOL(pwm_config);
64
pwm_enable(struct pwm_device * pwm)65 int 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 }
77 EXPORT_SYMBOL(pwm_enable);
78
pwm_disable(struct pwm_device * pwm)79 void 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 }
91 EXPORT_SYMBOL(pwm_disable);
92
pwm_request(int pwm_id,const char * label)93 struct 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 }
107 EXPORT_SYMBOL(pwm_request);
108
pwm_free(struct pwm_device * pwm)109 void pwm_free(struct pwm_device *pwm)
110 {
111 pwm_disable(pwm);
112 }
113 EXPORT_SYMBOL(pwm_free);
114
ab8500_pwm_probe(struct platform_device * pdev)115 static 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
ab8500_pwm_remove(struct platform_device * pdev)135 static 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
144 static 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
ab8500_pwm_init(void)153 static int __init ab8500_pwm_init(void)
154 {
155 return platform_driver_register(&ab8500_pwm_driver);
156 }
157
ab8500_pwm_exit(void)158 static void __exit ab8500_pwm_exit(void)
159 {
160 platform_driver_unregister(&ab8500_pwm_driver);
161 }
162
163 subsys_initcall(ab8500_pwm_init);
164 module_exit(ab8500_pwm_exit);
165 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
166 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
167 MODULE_ALIAS("AB8500 PWM driver");
168 MODULE_LICENSE("GPL v2");
169