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
27 struct pwm_device {
28 struct device *dev;
29 struct list_head node;
30 const char *label;
31 unsigned int pwm_id;
32 };
33
34 static LIST_HEAD(pwm_list);
35
pwm_config(struct pwm_device * pwm,int duty_ns,int period_ns)36 int 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 }
64 EXPORT_SYMBOL(pwm_config);
65
pwm_enable(struct pwm_device * pwm)66 int 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 }
78 EXPORT_SYMBOL(pwm_enable);
79
pwm_disable(struct pwm_device * pwm)80 void 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 }
92 EXPORT_SYMBOL(pwm_disable);
93
pwm_request(int pwm_id,const char * label)94 struct 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 }
108 EXPORT_SYMBOL(pwm_request);
109
pwm_free(struct pwm_device * pwm)110 void pwm_free(struct pwm_device *pwm)
111 {
112 pwm_disable(pwm);
113 }
114 EXPORT_SYMBOL(pwm_free);
115
ab8500_pwm_probe(struct platform_device * pdev)116 static 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
ab8500_pwm_remove(struct platform_device * pdev)136 static 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
145 static 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
ab8500_pwm_init(void)154 static int __init ab8500_pwm_init(void)
155 {
156 return platform_driver_register(&ab8500_pwm_driver);
157 }
158
ab8500_pwm_exit(void)159 static void __exit ab8500_pwm_exit(void)
160 {
161 platform_driver_unregister(&ab8500_pwm_driver);
162 }
163
164 subsys_initcall(ab8500_pwm_init);
165 module_exit(ab8500_pwm_exit);
166 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
167 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
168 MODULE_ALIAS("platform:ab8500-pwm");
169 MODULE_LICENSE("GPL v2");
170