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/drivers/misc/ab8500-pwm.c

https://bitbucket.org/ndreys/linux-sunxi
C | 168 lines | 122 code | 23 blank | 23 comment | 7 complexity | 90ebc20bb7501c9f54ccec638f077b98 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  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("AB8500 PWM driver");
168MODULE_LICENSE("GPL v2");