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
  23 struct ab8500_pwm_chip {
  24         struct pwm_chip chip;
  25 };
  26
  27 static 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
  57 static 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
  70 static 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
  82 static 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
  89 static 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
 117 static 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
 131 static struct platform_driver ab8500_pwm_driver = {
 132         .driver = {
 133                 .name = "ab8500-pwm",
 134         },
 135         .probe = ab8500_pwm_probe,
 136         .remove = ab8500_pwm_remove,
 137 };
 138 module_platform_driver(ab8500_pwm_driver);
 139
 140 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
 141 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
 142 MODULE_ALIAS("platform:ab8500-pwm");
 143 MODULE_LICENSE("GPL v2");