1/*
  2 * twl6030_pwm.c
  3 * Driver for PHOENIX (TWL6030) Pulse Width Modulator
  4 *
  5 * Copyright (C) 2010 Texas Instruments
  6 * Author: Hemanth V <hemanthv@ti.com>
  7 *
  8 * This program is free software; you can redistribute it and/or modify it
  9 * under the terms of the GNU General Public License version 2 as published by
 10 * the Free Software Foundation.
 11 *
 12 * This program is distributed in the hope that it will be useful, but WITHOUT
 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 15 * more details.
 16 *
 17 * You should have received a copy of the GNU General Public License along with
 18 * this program.  If not, see <http://www.gnu.org/licenses/>.
 19 */
 20
 21#include <linux/module.h>
 22#include <linux/platform_device.h>
 23#include <linux/i2c/twl.h>
 24#include <linux/slab.h>
 25
 26#define LED_PWM_CTRL1	0xF4
 27#define LED_PWM_CTRL2	0xF5
 28
 29/* Max value for CTRL1 register */
 30#define PWM_CTRL1_MAX	255
 31
 32/* Pull down disable */
 33#define PWM_CTRL2_DIS_PD	(1 << 6)
 34
 35/* Current control 2.5 milli Amps */
 36#define PWM_CTRL2_CURR_02	(2 << 4)
 37
 38/* LED supply source */
 39#define PWM_CTRL2_SRC_VAC	(1 << 2)
 40
 41/* LED modes */
 42#define PWM_CTRL2_MODE_HW	(0 << 0)
 43#define PWM_CTRL2_MODE_SW	(1 << 0)
 44#define PWM_CTRL2_MODE_DIS	(2 << 0)
 45
 46#define PWM_CTRL2_MODE_MASK	0x3
 47
 48struct pwm_device {
 49	const char *label;
 50	unsigned int pwm_id;
 51};
 52
 53int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
 54{
 55	u8 duty_cycle;
 56	int ret;
 57
 58	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
 59		return -EINVAL;
 60
 61	duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns;
 62
 63	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1);
 64
 65	if (ret < 0) {
 66		pr_err("%s: Failed to configure PWM, Error %d\n",
 67			pwm->label, ret);
 68		return ret;
 69	}
 70	return 0;
 71}
 72EXPORT_SYMBOL(pwm_config);
 73
 74int pwm_enable(struct pwm_device *pwm)
 75{
 76	u8 val;
 77	int ret;
 78
 79	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
 80	if (ret < 0) {
 81		pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret);
 82		return ret;
 83	}
 84
 85	/* Change mode to software control */
 86	val &= ~PWM_CTRL2_MODE_MASK;
 87	val |= PWM_CTRL2_MODE_SW;
 88
 89	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
 90	if (ret < 0) {
 91		pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret);
 92		return ret;
 93	}
 94
 95	twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
 96	return 0;
 97}
 98EXPORT_SYMBOL(pwm_enable);
 99
100void pwm_disable(struct pwm_device *pwm)
101{
102	u8 val;
103	int ret;
104
105	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
106	if (ret < 0) {
107		pr_err("%s: Failed to disable PWM, Error %d\n",
108			pwm->label, ret);
109		return;
110	}
111
112	val &= ~PWM_CTRL2_MODE_MASK;
113	val |= PWM_CTRL2_MODE_HW;
114
115	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
116	if (ret < 0) {
117		pr_err("%s: Failed to disable PWM, Error %d\n",
118			pwm->label, ret);
119		return;
120	}
121	return;
122}
123EXPORT_SYMBOL(pwm_disable);
124
125struct pwm_device *pwm_request(int pwm_id, const char *label)
126{
127	u8 val;
128	int ret;
129	struct pwm_device *pwm;
130
131	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
132	if (pwm == NULL) {
133		pr_err("%s: failed to allocate memory\n", label);
134		return NULL;
135	}
136
137	pwm->label = label;
138	pwm->pwm_id = pwm_id;
139
140	/* Configure PWM */
141	val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC |
142		PWM_CTRL2_MODE_HW;
143
144	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
145
146	if (ret < 0) {
147		pr_err("%s: Failed to configure PWM, Error %d\n",
148			 pwm->label, ret);
149
150		kfree(pwm);
151		return NULL;
152	}
153
154	return pwm;
155}
156EXPORT_SYMBOL(pwm_request);
157
158void pwm_free(struct pwm_device *pwm)
159{
160	pwm_disable(pwm);
161	kfree(pwm);
162}
163EXPORT_SYMBOL(pwm_free);
164
165MODULE_LICENSE("GPL");