linux/drivers/pwm/pwm-ab8500.c
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   1/*
   2 * Copyright (C) ST-Ericsson SA 2010
   3 *
   4 * Author: Arun R Murthy <arun.murthy@stericsson.com>
   5 * License terms: GNU General Public License (GPL) version 2
   6 */
   7#include <linux/err.h>
   8#include <linux/platform_device.h>
   9#include <linux/slab.h>
  10#include <linux/pwm.h>
  11#include <linux/mfd/abx500.h>
  12#include <linux/mfd/abx500/ab8500.h>
  13#include <linux/module.h>
  14
  15/*
  16 * PWM Out generators
  17 * Bank: 0x10
  18 */
  19#define AB8500_PWM_OUT_CTRL1_REG        0x60
  20#define AB8500_PWM_OUT_CTRL2_REG        0x61
  21#define AB8500_PWM_OUT_CTRL7_REG        0x66
  22
  23/* backlight driver constants */
  24#define ENABLE_PWM                      1
  25#define DISABLE_PWM                     0
  26
  27struct ab8500_pwm_chip {
  28        struct pwm_chip chip;
  29};
  30
  31static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  32                             int duty_ns, int period_ns)
  33{
  34        int ret = 0;
  35        unsigned int higher_val, lower_val;
  36        u8 reg;
  37
  38        /*
  39         * get the first 8 bits that are be written to
  40         * AB8500_PWM_OUT_CTRL1_REG[0:7]
  41         */
  42        lower_val = duty_ns & 0x00FF;
  43        /*
  44         * get bits [9:10] that are to be written to
  45         * AB8500_PWM_OUT_CTRL2_REG[0:1]
  46         */
  47        higher_val = ((duty_ns & 0x0300) >> 8);
  48
  49        reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
  50
  51        ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  52                        reg, (u8)lower_val);
  53        if (ret < 0)
  54                return ret;
  55        ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  56                        (reg + 1), (u8)higher_val);
  57
  58        return ret;
  59}
  60
  61static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  62{
  63        int ret;
  64
  65        ret = abx500_mask_and_set_register_interruptible(chip->dev,
  66                                AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  67                                1 << (chip->base - 1), ENABLE_PWM);
  68        if (ret < 0)
  69                dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
  70                                                        pwm->label, ret);
  71        return ret;
  72}
  73
  74static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  75{
  76        int ret;
  77
  78        ret = abx500_mask_and_set_register_interruptible(chip->dev,
  79                                AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  80                                1 << (chip->base - 1), DISABLE_PWM);
  81        if (ret < 0)
  82                dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
  83                                                        pwm->label, ret);
  84        return;
  85}
  86
  87static const struct pwm_ops ab8500_pwm_ops = {
  88        .config = ab8500_pwm_config,
  89        .enable = ab8500_pwm_enable,
  90        .disable = ab8500_pwm_disable,
  91};
  92
  93static int __devinit ab8500_pwm_probe(struct platform_device *pdev)
  94{
  95        struct ab8500_pwm_chip *ab8500;
  96        int err;
  97
  98        /*
  99         * Nothing to be done in probe, this is required to get the
 100         * device which is required for ab8500 read and write
 101         */
 102        ab8500 = kzalloc(sizeof(*ab8500), GFP_KERNEL);
 103        if (ab8500 == NULL) {
 104                dev_err(&pdev->dev, "failed to allocate memory\n");
 105                return -ENOMEM;
 106        }
 107
 108        ab8500->chip.dev = &pdev->dev;
 109        ab8500->chip.ops = &ab8500_pwm_ops;
 110        ab8500->chip.base = pdev->id;
 111        ab8500->chip.npwm = 1;
 112
 113        err = pwmchip_add(&ab8500->chip);
 114        if (err < 0) {
 115                kfree(ab8500);
 116                return err;
 117        }
 118
 119        dev_dbg(&pdev->dev, "pwm probe successful\n");
 120        platform_set_drvdata(pdev, ab8500);
 121
 122        return 0;
 123}
 124
 125static int __devexit ab8500_pwm_remove(struct platform_device *pdev)
 126{
 127        struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
 128        int err;
 129
 130        err = pwmchip_remove(&ab8500->chip);
 131        if (err < 0)
 132                return err;
 133
 134        dev_dbg(&pdev->dev, "pwm driver removed\n");
 135        kfree(ab8500);
 136
 137        return 0;
 138}
 139
 140static struct platform_driver ab8500_pwm_driver = {
 141        .driver = {
 142                .name = "ab8500-pwm",
 143                .owner = THIS_MODULE,
 144        },
 145        .probe = ab8500_pwm_probe,
 146        .remove = __devexit_p(ab8500_pwm_remove),
 147};
 148module_platform_driver(ab8500_pwm_driver);
 149
 150MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
 151MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
 152MODULE_ALIAS("platform:ab8500-pwm");
 153MODULE_LICENSE("GPL v2");
 154
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