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         unsigned int hwid;
  26 };
  27
  28 static struct ab8500_pwm_chip *ab8500_pwm_from_chip(struct pwm_chip *chip)
  29 {
  30         return container_of(chip, struct ab8500_pwm_chip, chip);
  31 }
  32
  33 static int ab8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
  34                             const struct pwm_state *state)
  35 {
  36         int ret;
  37         u8 reg;
  38         unsigned int higher_val, lower_val;
  39         struct ab8500_pwm_chip *ab8500 = ab8500_pwm_from_chip(chip);
  40
  41         if (state->polarity != PWM_POLARITY_NORMAL)
  42                 return -EINVAL;
  43
  44         if (!state->enabled) {
  45                 ret = abx500_mask_and_set_register_interruptible(chip->dev,
  46                                         AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  47                                         1 << ab8500->hwid, 0);
  48
  49                 if (ret < 0)
  50                         dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
  51                                                                 pwm->label, ret);
  52                 return ret;
  53         }
  54
  55         /*
  56          * get the first 8 bits that are be written to
  57          * AB8500_PWM_OUT_CTRL1_REG[0:7]
  58          */
  59         lower_val = state->duty_cycle & 0x00FF;
  60         /*
  61          * get bits [9:10] that are to be written to
  62          * AB8500_PWM_OUT_CTRL2_REG[0:1]
  63          */
  64         higher_val = ((state->duty_cycle & 0x0300) >> 8);
  65
  66         reg = AB8500_PWM_OUT_CTRL1_REG + (ab8500->hwid * 2);
  67
  68         ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  69                         reg, (u8)lower_val);
  70         if (ret < 0)
  71                 return ret;
  72
  73         ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
  74                         (reg + 1), (u8)higher_val);
  75         if (ret < 0)
  76                 return ret;
  77
  78         ret = abx500_mask_and_set_register_interruptible(chip->dev,
  79                                 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
  80                                 1 << ab8500->hwid, 1 << ab8500->hwid);
  81         if (ret < 0)
  82                 dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
  83                                                         pwm->label, ret);
  84
  85         return ret;
  86 }
  87
  88 static const struct pwm_ops ab8500_pwm_ops = {
  89         .apply = ab8500_pwm_apply,
  90         .owner = THIS_MODULE,
  91 };
  92
  93 static int ab8500_pwm_probe(struct platform_device *pdev)
  94 {
  95         struct ab8500_pwm_chip *ab8500;
  96         int err;
  97
  98         if (pdev->id < 1 || pdev->id > 31)
  99                 return dev_err_probe(&pdev->dev, EINVAL, "Invalid device id %d\n", pdev->id);
 100
 101         /*
 102          * Nothing to be done in probe, this is required to get the
 103          * device which is required for ab8500 read and write
 104          */
 105         ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
 106         if (ab8500 == NULL)
 107                 return -ENOMEM;
 108
 109         ab8500->chip.dev = &pdev->dev;
 110         ab8500->chip.ops = &ab8500_pwm_ops;
 111         ab8500->chip.npwm = 1;
 112         ab8500->hwid = pdev->id - 1;
 113
 114         err = devm_pwmchip_add(&pdev->dev, &ab8500->chip);
 115         if (err < 0)
 116                 return dev_err_probe(&pdev->dev, err, "Failed to add pwm chip\n");
 117
 118         dev_dbg(&pdev->dev, "pwm probe successful\n");
 119
 120         return 0;
 121 }
 122
 123 static struct platform_driver ab8500_pwm_driver = {
 124         .driver = {
 125                 .name = "ab8500-pwm",
 126         },
 127         .probe = ab8500_pwm_probe,
 128 };
 129 module_platform_driver(ab8500_pwm_driver);
 130
 131 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
 132 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
 133 MODULE_ALIAS("platform:ab8500-pwm");
 134 MODULE_LICENSE("GPL v2");