linux/drivers/pwm/pwm-twl6030.c
<<
>>
Prefs
   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/pwm.h>
  24#include <linux/i2c/twl.h>
  25#include <linux/slab.h>
  26
  27#define LED_PWM_CTRL1   0xF4
  28#define LED_PWM_CTRL2   0xF5
  29
  30/* Max value for CTRL1 register */
  31#define PWM_CTRL1_MAX   255
  32
  33/* Pull down disable */
  34#define PWM_CTRL2_DIS_PD        (1 << 6)
  35
  36/* Current control 2.5 milli Amps */
  37#define PWM_CTRL2_CURR_02       (2 << 4)
  38
  39/* LED supply source */
  40#define PWM_CTRL2_SRC_VAC       (1 << 2)
  41
  42/* LED modes */
  43#define PWM_CTRL2_MODE_HW       (0 << 0)
  44#define PWM_CTRL2_MODE_SW       (1 << 0)
  45#define PWM_CTRL2_MODE_DIS      (2 << 0)
  46
  47#define PWM_CTRL2_MODE_MASK     0x3
  48
  49struct twl6030_pwm_chip {
  50        struct pwm_chip chip;
  51};
  52
  53static int twl6030_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  54{
  55        int ret;
  56        u8 val;
  57
  58        /* Configure PWM */
  59        val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC |
  60              PWM_CTRL2_MODE_HW;
  61
  62        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
  63        if (ret < 0) {
  64                dev_err(chip->dev, "%s: Failed to configure PWM, Error %d\n",
  65                        pwm->label, ret);
  66                return ret;
  67        }
  68
  69        return 0;
  70}
  71
  72static int twl6030_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  73                              int duty_ns, int period_ns)
  74{
  75        u8 duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns;
  76        int ret;
  77
  78        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1);
  79        if (ret < 0) {
  80                pr_err("%s: Failed to configure PWM, Error %d\n",
  81                        pwm->label, ret);
  82                return ret;
  83        }
  84
  85        return 0;
  86}
  87
  88static int twl6030_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  89{
  90        int ret;
  91        u8 val;
  92
  93        ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
  94        if (ret < 0) {
  95                dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
  96                        pwm->label, ret);
  97                return ret;
  98        }
  99
 100        /* Change mode to software control */
 101        val &= ~PWM_CTRL2_MODE_MASK;
 102        val |= PWM_CTRL2_MODE_SW;
 103
 104        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
 105        if (ret < 0) {
 106                dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
 107                        pwm->label, ret);
 108                return ret;
 109        }
 110
 111        twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
 112        return 0;
 113}
 114
 115static void twl6030_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 116{
 117        int ret;
 118        u8 val;
 119
 120        ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
 121        if (ret < 0) {
 122                dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
 123                        pwm->label, ret);
 124                return;
 125        }
 126
 127        val &= ~PWM_CTRL2_MODE_MASK;
 128        val |= PWM_CTRL2_MODE_HW;
 129
 130        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
 131        if (ret < 0) {
 132                dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
 133                        pwm->label, ret);
 134        }
 135}
 136
 137static const struct pwm_ops twl6030_pwm_ops = {
 138        .request = twl6030_pwm_request,
 139        .config = twl6030_pwm_config,
 140        .enable = twl6030_pwm_enable,
 141        .disable = twl6030_pwm_disable,
 142};
 143
 144static int twl6030_pwm_probe(struct platform_device *pdev)
 145{
 146        struct twl6030_pwm_chip *twl6030;
 147        int ret;
 148
 149        twl6030 = devm_kzalloc(&pdev->dev, sizeof(*twl6030), GFP_KERNEL);
 150        if (!twl6030)
 151                return -ENOMEM;
 152
 153        twl6030->chip.dev = &pdev->dev;
 154        twl6030->chip.ops = &twl6030_pwm_ops;
 155        twl6030->chip.base = -1;
 156        twl6030->chip.npwm = 1;
 157
 158        ret = pwmchip_add(&twl6030->chip);
 159        if (ret < 0)
 160                return ret;
 161
 162        platform_set_drvdata(pdev, twl6030);
 163
 164        return 0;
 165}
 166
 167static int twl6030_pwm_remove(struct platform_device *pdev)
 168{
 169        struct twl6030_pwm_chip *twl6030 = platform_get_drvdata(pdev);
 170
 171        return pwmchip_remove(&twl6030->chip);
 172}
 173
 174static struct platform_driver twl6030_pwm_driver = {
 175        .driver = {
 176                .name = "twl6030-pwm",
 177        },
 178        .probe = twl6030_pwm_probe,
 179        .remove = __devexit_p(twl6030_pwm_remove),
 180};
 181module_platform_driver(twl6030_pwm_driver);
 182
 183MODULE_ALIAS("platform:twl6030-pwm");
 184MODULE_LICENSE("GPL");
 185
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.