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/*
* twl6030_pwm.c
* Driver for PHOENIX (TWL6030) Pulse Width Modulator
*
* Copyright (C) 2010 Texas Instruments
* Author: Hemanth V <hemanthv@ti.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/i2c/twl.h>
#include <linux/slab.h>
#define LED_PWM_CTRL1 0xF4
#define LED_PWM_CTRL2 0xF5
/* Max value for CTRL1 register */
#define PWM_CTRL1_MAX 255
/* Pull down disable */
#define PWM_CTRL2_DIS_PD (1 << 6)
/* Current control 2.5 milli Amps */
#define PWM_CTRL2_CURR_02 (2 << 4)
/* LED supply source */
#define PWM_CTRL2_SRC_VAC (1 << 2)
/* LED modes */
#define PWM_CTRL2_MODE_HW (0 << 0)
#define PWM_CTRL2_MODE_SW (1 << 0)
#define PWM_CTRL2_MODE_DIS (2 << 0)
#define PWM_CTRL2_MODE_MASK 0x3
struct pwm_device {
const char *label;
unsigned int pwm_id;
};
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
u8 duty_cycle;
int ret;
if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
return -EINVAL;
duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1);
if (ret < 0) {
pr_err("%s: Failed to configure PWM, Error %d\n",
pwm->label, ret);
return ret;
}
return 0;
}
EXPORT_SYMBOL(pwm_config);
int pwm_enable(struct pwm_device *pwm)
{
u8 val;
int ret;
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
if (ret < 0) {
pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret);
return ret;
}
/* Change mode to software control */
val &= ~PWM_CTRL2_MODE_MASK;
val |= PWM_CTRL2_MODE_SW;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
if (ret < 0) {
pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret);
return ret;
}
twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
return 0;
}
EXPORT_SYMBOL(pwm_enable);
void pwm_disable(struct pwm_device *pwm)
{
u8 val;
int ret;
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
if (ret < 0) {
pr_err("%s: Failed to disable PWM, Error %d\n",
pwm->label, ret);
return;
}
val &= ~PWM_CTRL2_MODE_MASK;
val |= PWM_CTRL2_MODE_HW;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
if (ret < 0) {
pr_err("%s: Failed to disable PWM, Error %d\n",
pwm->label, ret);
return;
}
return;
}
EXPORT_SYMBOL(pwm_disable);
struct pwm_device *pwm_request(int pwm_id, const char *label)
{
u8 val;
int ret;
struct pwm_device *pwm;
pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
if (pwm == NULL) {
pr_err("%s: failed to allocate memory\n", label);
return NULL;
}
pwm->label = label;
pwm->pwm_id = pwm_id;
/* Configure PWM */
val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC |
PWM_CTRL2_MODE_HW;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
if (ret < 0) {
pr_err("%s: Failed to configure PWM, Error %d\n",
pwm->label, ret);
kfree(pwm);
return NULL;
}
return pwm;
}
EXPORT_SYMBOL(pwm_request);
void pwm_free(struct pwm_device *pwm)
{
pwm_disable(pwm);
kfree(pwm);
}
EXPORT_SYMBOL(pwm_free);
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