185 lines
4.3 KiB
C
185 lines
4.3 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/pwm.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 twl6030_pwm_chip {
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struct pwm_chip chip;
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};
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static int twl6030_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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int ret;
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u8 val;
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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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dev_err(chip->dev, "%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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static int twl6030_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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u8 duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns;
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int ret;
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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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static int twl6030_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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int ret;
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u8 val;
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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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dev_err(chip->dev, "%s: Failed to enable 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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/* 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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dev_err(chip->dev, "%s: Failed to enable 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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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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static void twl6030_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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int ret;
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u8 val;
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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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dev_err(chip->dev, "%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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dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
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pwm->label, ret);
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}
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}
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static const struct pwm_ops twl6030_pwm_ops = {
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.request = twl6030_pwm_request,
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.config = twl6030_pwm_config,
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.enable = twl6030_pwm_enable,
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.disable = twl6030_pwm_disable,
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};
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static int twl6030_pwm_probe(struct platform_device *pdev)
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{
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struct twl6030_pwm_chip *twl6030;
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int ret;
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twl6030 = devm_kzalloc(&pdev->dev, sizeof(*twl6030), GFP_KERNEL);
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if (!twl6030)
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return -ENOMEM;
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twl6030->chip.dev = &pdev->dev;
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twl6030->chip.ops = &twl6030_pwm_ops;
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twl6030->chip.base = -1;
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twl6030->chip.npwm = 1;
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ret = pwmchip_add(&twl6030->chip);
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if (ret < 0)
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return ret;
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platform_set_drvdata(pdev, twl6030);
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return 0;
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}
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static int twl6030_pwm_remove(struct platform_device *pdev)
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{
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struct twl6030_pwm_chip *twl6030 = platform_get_drvdata(pdev);
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return pwmchip_remove(&twl6030->chip);
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}
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static struct platform_driver twl6030_pwm_driver = {
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.driver = {
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.name = "twl6030-pwm",
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},
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.probe = twl6030_pwm_probe,
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.remove = __devexit_p(twl6030_pwm_remove),
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};
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module_platform_driver(twl6030_pwm_driver);
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MODULE_ALIAS("platform:twl6030-pwm");
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MODULE_LICENSE("GPL");
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