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 const struct of_device_id ab8500_pwm_match[] = {
146	{ .compatible = "stericsson,ab8500-pwm", },
147	{}
148};
149
150static struct platform_driver ab8500_pwm_driver = {
151	.driver = {
152		.name = "ab8500-pwm",
153		.owner = THIS_MODULE,
154		.of_match_table = ab8500_pwm_match,
155	},
156	.probe = ab8500_pwm_probe,
157	.remove = __devexit_p(ab8500_pwm_remove),
158};
159
160static int __init ab8500_pwm_init(void)
161{
162	return platform_driver_register(&ab8500_pwm_driver);
163}
164
165static void __exit ab8500_pwm_exit(void)
166{
167	platform_driver_unregister(&ab8500_pwm_driver);
168}
169
170subsys_initcall(ab8500_pwm_init);
171module_exit(ab8500_pwm_exit);
172MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
173MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
174MODULE_ALIAS("platform:ab8500-pwm");
175MODULE_LICENSE("GPL v2");