mirror of
https://github.com/torvalds/linux.git
synced 2024-12-22 10:56:40 +00:00
31fc03df5d
TWL6030 supports PWM (Pulse Width Modulator) which is used to control charging LED. PWM allows for controlling brightness. This patch implements the APIs required by leds-pwm driver. Signed-off-by: Hemanth V <hemanthv@ti.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
164 lines
3.6 KiB
C
164 lines
3.6 KiB
C
/*
|
|
* 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);
|