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