drivers/gpio/gpio-axp209.c

   1 /*
   2  * AXP20x GPIO driver
   3  *
   4  * Copyright (C) 2016 Maxime Ripard <maxime.ripard@free-electrons.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under  the terms of the GNU General  Public License as published by the
   8  * Free Software Foundation;  either version 2 of the License, or (at your
   9  * option) any later version.
  10  */
  11
  12 #include <linux/bitops.h>
  13 #include <linux/device.h>
  14 #include <linux/gpio/driver.h>
  15 #include <linux/init.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mfd/axp20x.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/regmap.h>
  23 #include <linux/slab.h>
  24
  25 #define AXP20X_GPIO_FUNCTIONS           0x7
  26 #define AXP20X_GPIO_FUNCTION_OUT_LOW    0
  27 #define AXP20X_GPIO_FUNCTION_OUT_HIGH   1
  28 #define AXP20X_GPIO_FUNCTION_INPUT      2
  29
  30 struct axp20x_gpio {
  31         struct gpio_chip        chip;
  32         struct regmap           *regmap;
  33 };
  34
  35 static int axp20x_gpio_get_reg(unsigned offset)
  36 {
  37         switch (offset) {
  38         case 0:
  39                 return AXP20X_GPIO0_CTRL;
  40         case 1:
  41                 return AXP20X_GPIO1_CTRL;
  42         case 2:
  43                 return AXP20X_GPIO2_CTRL;
  44         }
  45
  46         return -EINVAL;
  47 }
  48
  49 static int axp20x_gpio_input(struct gpio_chip *chip, unsigned offset)
  50 {
  51         struct axp20x_gpio *gpio = gpiochip_get_data(chip);
  52         int reg;
  53
  54         reg = axp20x_gpio_get_reg(offset);
  55         if (reg < 0)
  56                 return reg;
  57
  58         return regmap_update_bits(gpio->regmap, reg,
  59                                   AXP20X_GPIO_FUNCTIONS,
  60                                   AXP20X_GPIO_FUNCTION_INPUT);
  61 }
  62
  63 static int axp20x_gpio_get(struct gpio_chip *chip, unsigned offset)
  64 {
  65         struct axp20x_gpio *gpio = gpiochip_get_data(chip);
  66         unsigned int val;
  67         int ret;
  68
  69         ret = regmap_read(gpio->regmap, AXP20X_GPIO20_SS, &val);
  70         if (ret)
  71                 return ret;
  72
  73         return !!(val & BIT(offset + 4));
  74 }
  75
  76 static int axp20x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
  77 {
  78         struct axp20x_gpio *gpio = gpiochip_get_data(chip);
  79         unsigned int val;
  80         int reg, ret;
  81
  82         reg = axp20x_gpio_get_reg(offset);
  83         if (reg < 0)
  84                 return reg;
  85
  86         ret = regmap_read(gpio->regmap, reg, &val);
  87         if (ret)
  88                 return ret;
  89
  90         /*
  91          * This shouldn't really happen if the pin is in use already,
  92          * or if it's not in use yet, it doesn't matter since we're
  93          * going to change the value soon anyway. Default to output.
  94          */
  95         if ((val & AXP20X_GPIO_FUNCTIONS) > 2)
  96                 return 0;
  97
  98         /*
  99          * The GPIO directions are the three lowest values.
 100          * 2 is input, 0 and 1 are output
 101          */
 102         return val & 2;
 103 }
 104
 105 static int axp20x_gpio_output(struct gpio_chip *chip, unsigned offset,
 106                               int value)
 107 {
 108         struct axp20x_gpio *gpio = gpiochip_get_data(chip);
 109         int reg;
 110
 111         reg = axp20x_gpio_get_reg(offset);
 112         if (reg < 0)
 113                 return reg;
 114
 115         return regmap_update_bits(gpio->regmap, reg,
 116                                   AXP20X_GPIO_FUNCTIONS,
 117                                   value ? AXP20X_GPIO_FUNCTION_OUT_HIGH
 118                                   : AXP20X_GPIO_FUNCTION_OUT_LOW);
 119 }
 120
 121 static void axp20x_gpio_set(struct gpio_chip *chip, unsigned offset,
 122                             int value)
 123 {
 124         axp20x_gpio_output(chip, offset, value);
 125 }
 126
 127 static int axp20x_gpio_probe(struct platform_device *pdev)
 128 {
 129         struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
 130         struct axp20x_gpio *gpio;
 131         int ret;
 132
 133         if (!of_device_is_available(pdev->dev.of_node))
 134                 return -ENODEV;
 135
 136         if (!axp20x) {
 137                 dev_err(&pdev->dev, "Parent drvdata not set\n");
 138                 return -EINVAL;
 139         }
 140
 141         gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
 142         if (!gpio)
 143                 return -ENOMEM;
 144
 145         gpio->chip.base                 = -1;
 146         gpio->chip.can_sleep            = true;
 147         gpio->chip.parent               = &pdev->dev;
 148         gpio->chip.label                = dev_name(&pdev->dev);
 149         gpio->chip.owner                = THIS_MODULE;
 150         gpio->chip.get                  = axp20x_gpio_get;
 151         gpio->chip.get_direction        = axp20x_gpio_get_direction;
 152         gpio->chip.set                  = axp20x_gpio_set;
 153         gpio->chip.direction_input      = axp20x_gpio_input;
 154         gpio->chip.direction_output     = axp20x_gpio_output;
 155         gpio->chip.ngpio                = 3;
 156
 157         gpio->regmap = axp20x->regmap;
 158
 159         ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
 160         if (ret) {
 161                 dev_err(&pdev->dev, "Failed to register GPIO chip\n");
 162                 return ret;
 163         }
 164
 165         dev_info(&pdev->dev, "AXP209 GPIO driver loaded\n");
 166
 167         return 0;
 168 }
 169
 170 static const struct of_device_id axp20x_gpio_match[] = {
 171         { .compatible = "x-powers,axp209-gpio" },
 172         { }
 173 };
 174 MODULE_DEVICE_TABLE(of, axp20x_gpio_match);
 175
 176 static struct platform_driver axp20x_gpio_driver = {
 177         .probe          = axp20x_gpio_probe,
 178         .driver = {
 179                 .name           = "axp20x-gpio",
 180                 .of_match_table = axp20x_gpio_match,
 181         },
 182 };
 183
 184 module_platform_driver(axp20x_gpio_driver);
 185
 186 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
 187 MODULE_DESCRIPTION("AXP20x PMIC GPIO driver");
 188 MODULE_LICENSE("GPL");