drivers/pwm/pwm-ab8500.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) ST-Ericsson SA 2010
   4  *
   5  * Author: Arun R Murthy <arun.murthy@stericsson.com>
   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_apply(struct pwm_chip *chip, struct pwm_device *pwm,
  28                             const struct pwm_state *state)
  29 {
  30         int ret;
  31         u8 reg;
  32         unsigned int higher_val, lower_val;
  33
  34         if (state->polarity != PWM_POLARITY_NORMAL)
  35                 return -EINVAL;
  36
  37         if (!state->enabled) {
  38                 ret = abx500_mask_and_set_register_interruptible(chip->dev,
  39                                         AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  40                                         1 << (chip->base - 1), 0);
  41
  42                 if (ret < 0)
  43                         dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
  44                                                                 pwm->label, ret);
  45                 return ret;
  46         }
  47
  48         /*
  49          * get the first 8 bits that are be written to
  50          * AB8500_PWM_OUT_CTRL1_REG[0:7]
  51          */
  52         lower_val = state->duty_cycle & 0x00FF;
  53         /*
  54          * get bits [9:10] that are to be written to
  55          * AB8500_PWM_OUT_CTRL2_REG[0:1]
  56          */
  57         higher_val = ((state->duty_cycle & 0x0300) >> 8);
  58
  59         reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
  60
  61         ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  62                         reg, (u8)lower_val);
  63         if (ret < 0)
  64                 return ret;
  65
  66         ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  67                         (reg + 1), (u8)higher_val);
  68         if (ret < 0)
  69                 return ret;
  70
  71         ret = abx500_mask_and_set_register_interruptible(chip->dev,
  72                                 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  73                                 1 << (chip->base - 1), 1 << (chip->base - 1));
  74         if (ret < 0)
  75                 dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
  76                                                         pwm->label, ret);
  77
  78         return ret;
  79 }
  80
  81 static const struct pwm_ops ab8500_pwm_ops = {
  82         .apply = ab8500_pwm_apply,
  83         .owner = THIS_MODULE,
  84 };
  85
  86 static int ab8500_pwm_probe(struct platform_device *pdev)
  87 {
  88         struct ab8500_pwm_chip *ab8500;
  89         int err;
  90
  91         /*
  92          * Nothing to be done in probe, this is required to get the
  93          * device which is required for ab8500 read and write
  94          */
  95         ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
  96         if (ab8500 == NULL)
  97                 return -ENOMEM;
  98
  99         ab8500->chip.dev = &pdev->dev;
 100         ab8500->chip.ops = &ab8500_pwm_ops;
 101         ab8500->chip.npwm = 1;
 102
 103         err = pwmchip_add(&ab8500->chip);
 104         if (err < 0)
 105                 return dev_err_probe(&pdev->dev, err, "Failed to add pwm chip\n");
 106
 107         dev_dbg(&pdev->dev, "pwm probe successful\n");
 108         platform_set_drvdata(pdev, ab8500);
 109
 110         return 0;
 111 }
 112
 113 static int ab8500_pwm_remove(struct platform_device *pdev)
 114 {
 115         struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
 116         int err;
 117
 118         err = pwmchip_remove(&ab8500->chip);
 119         if (err < 0)
 120                 return err;
 121
 122         dev_dbg(&pdev->dev, "pwm driver removed\n");
 123
 124         return 0;
 125 }
 126
 127 static struct platform_driver ab8500_pwm_driver = {
 128         .driver = {
 129                 .name = "ab8500-pwm",
 130         },
 131         .probe = ab8500_pwm_probe,
 132         .remove = ab8500_pwm_remove,
 133 };
 134 module_platform_driver(ab8500_pwm_driver);
 135
 136 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
 137 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
 138 MODULE_ALIAS("platform:ab8500-pwm");
 139 MODULE_LICENSE("GPL v2");