LXR linux/drivers/pwm/pwm-ab8500.c

   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
  23struct ab8500_pwm_chip {
  24        struct pwm_chip chip;
  25};
  26
  27static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  28                             int duty_ns, int period_ns)
  29{
  30        int ret = 0;
  31        unsigned int higher_val, lower_val;
  32        u8 reg;
  33
  34        /*
  35         * get the first 8 bits that are be written to
  36         * AB8500_PWM_OUT_CTRL1_REG[0:7]
  37         */
  38        lower_val = duty_ns & 0x00FF;
  39        /*
  40         * get bits [9:10] that are to be written to
  41         * AB8500_PWM_OUT_CTRL2_REG[0:1]
  42         */
  43        higher_val = ((duty_ns & 0x0300) >> 8);
  44
  45        reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
  46
  47        ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  48                        reg, (u8)lower_val);
  49        if (ret < 0)
  50                return ret;
  51        ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  52                        (reg + 1), (u8)higher_val);
  53
  54        return ret;
  55}
  56
  57static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  58{
  59        int ret;
  60
  61        ret = abx500_mask_and_set_register_interruptible(chip->dev,
  62                                AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  63                                1 << (chip->base - 1), 1 << (chip->base - 1));
  64        if (ret < 0)
  65                dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
  66                                                        pwm->label, ret);
  67        return ret;
  68}
  69
  70static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  71{
  72        int ret;
  73
  74        ret = abx500_mask_and_set_register_interruptible(chip->dev,
  75                                AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  76                                1 << (chip->base - 1), 0);
  77        if (ret < 0)
  78                dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
  79                                                        pwm->label, ret);
  80}
  81
  82static const struct pwm_ops ab8500_pwm_ops = {
  83        .config = ab8500_pwm_config,
  84        .enable = ab8500_pwm_enable,
  85        .disable = ab8500_pwm_disable,
  86        .owner = THIS_MODULE,
  87};
  88
  89static int ab8500_pwm_probe(struct platform_device *pdev)
  90{
  91        struct ab8500_pwm_chip *ab8500;
  92        int err;
  93
  94        /*
  95         * Nothing to be done in probe, this is required to get the
  96         * device which is required for ab8500 read and write
  97         */
  98        ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
  99        if (ab8500 == NULL)
 100                return -ENOMEM;
 101
 102        ab8500->chip.dev = &pdev->dev;
 103        ab8500->chip.ops = &ab8500_pwm_ops;
 104        ab8500->chip.base = pdev->id;
 105        ab8500->chip.npwm = 1;
 106
 107        err = pwmchip_add(&ab8500->chip);
 108        if (err < 0)
 109                return err;
 110
 111        dev_dbg(&pdev->dev, "pwm probe successful\n");
 112        platform_set_drvdata(pdev, ab8500);
 113
 114        return 0;
 115}
 116
 117static int ab8500_pwm_remove(struct platform_device *pdev)
 118{
 119        struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
 120        int err;
 121
 122        err = pwmchip_remove(&ab8500->chip);
 123        if (err < 0)
 124                return err;
 125
 126        dev_dbg(&pdev->dev, "pwm driver removed\n");
 127
 128        return 0;
 129}
 130
 131static struct platform_driver ab8500_pwm_driver = {
 132        .driver = {
 133                .name = "ab8500-pwm",
 134        },
 135        .probe = ab8500_pwm_probe,
 136        .remove = ab8500_pwm_remove,
 137};
 138module_platform_driver(ab8500_pwm_driver);
 139
 140MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
 141MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
 142MODULE_ALIAS("platform:ab8500-pwm");
 143MODULE_LICENSE("GPL v2");
 144