drivers/gpio/gpio-bd71828.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 // Copyright (C) 2018 ROHM Semiconductors
   3
   4 #include <linux/gpio/driver.h>
   5 #include <linux/mfd/rohm-bd71828.h>
   6 #include <linux/module.h>
   7 #include <linux/platform_device.h>
   8 #include <linux/regmap.h>
   9
  10 #define GPIO_OUT_REG(off) (BD71828_REG_GPIO_CTRL1 + (off))
  11 #define HALL_GPIO_OFFSET 3
  12
  13 struct bd71828_gpio {
  14         struct regmap *regmap;
  15         struct device *dev;
  16         struct gpio_chip gpio;
  17 };
  18
  19 static void bd71828_gpio_set(struct gpio_chip *chip, unsigned int offset,
  20                              int value)
  21 {
  22         int ret;
  23         struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
  24         u8 val = (value) ? BD71828_GPIO_OUT_HI : BD71828_GPIO_OUT_LO;
  25
  26         /*
  27          * The HALL input pin can only be used as input. If this is the pin
  28          * we are dealing with - then we are done
  29          */
  30         if (offset == HALL_GPIO_OFFSET)
  31                 return;
  32
  33         ret = regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
  34                                  BD71828_GPIO_OUT_MASK, val);
  35         if (ret)
  36                 dev_err(bdgpio->dev, "Could not set gpio to %d\n", value);
  37 }
  38
  39 static int bd71828_gpio_get(struct gpio_chip *chip, unsigned int offset)
  40 {
  41         int ret;
  42         unsigned int val;
  43         struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
  44
  45         if (offset == HALL_GPIO_OFFSET)
  46                 ret = regmap_read(bdgpio->regmap, BD71828_REG_IO_STAT,
  47                                   &val);
  48         else
  49                 ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset),
  50                                   &val);
  51         if (!ret)
  52                 ret = (val & BD71828_GPIO_OUT_MASK);
  53
  54         return ret;
  55 }
  56
  57 static int bd71828_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
  58                                    unsigned long config)
  59 {
  60         struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
  61
  62         if (offset == HALL_GPIO_OFFSET)
  63                 return -ENOTSUPP;
  64
  65         switch (pinconf_to_config_param(config)) {
  66         case PIN_CONFIG_DRIVE_OPEN_DRAIN:
  67                 return regmap_update_bits(bdgpio->regmap,
  68                                           GPIO_OUT_REG(offset),
  69                                           BD71828_GPIO_DRIVE_MASK,
  70                                           BD71828_GPIO_OPEN_DRAIN);
  71         case PIN_CONFIG_DRIVE_PUSH_PULL:
  72                 return regmap_update_bits(bdgpio->regmap,
  73                                           GPIO_OUT_REG(offset),
  74                                           BD71828_GPIO_DRIVE_MASK,
  75                                           BD71828_GPIO_PUSH_PULL);
  76         default:
  77                 break;
  78         }
  79         return -ENOTSUPP;
  80 }
  81
  82 static int bd71828_get_direction(struct gpio_chip *chip, unsigned int offset)
  83 {
  84         /*
  85          * Pin usage is selected by OTP data. We can't read it runtime. Hence
  86          * we trust that if the pin is not excluded by "gpio-reserved-ranges"
  87          * the OTP configuration is set to OUT. (Other pins but HALL input pin
  88          * on BD71828 can't really be used for general purpose input - input
  89          * states are used for specific cases like regulator control or
  90          * PMIC_ON_REQ.
  91          */
  92         if (offset == HALL_GPIO_OFFSET)
  93                 return GPIO_LINE_DIRECTION_IN;
  94
  95         return GPIO_LINE_DIRECTION_OUT;
  96 }
  97
  98 static int bd71828_probe(struct platform_device *pdev)
  99 {
 100         struct device *dev = &pdev->dev;
 101         struct bd71828_gpio *bdgpio;
 102
 103         bdgpio = devm_kzalloc(dev, sizeof(*bdgpio), GFP_KERNEL);
 104         if (!bdgpio)
 105                 return -ENOMEM;
 106
 107         bdgpio->dev = dev;
 108         bdgpio->gpio.parent = dev->parent;
 109         bdgpio->gpio.label = "bd71828-gpio";
 110         bdgpio->gpio.owner = THIS_MODULE;
 111         bdgpio->gpio.get_direction = bd71828_get_direction;
 112         bdgpio->gpio.set_config = bd71828_gpio_set_config;
 113         bdgpio->gpio.can_sleep = true;
 114         bdgpio->gpio.get = bd71828_gpio_get;
 115         bdgpio->gpio.set = bd71828_gpio_set;
 116         bdgpio->gpio.base = -1;
 117
 118         /*
 119          * See if we need some implementation to mark some PINs as
 120          * not controllable based on DT info or if core can handle
 121          * "gpio-reserved-ranges" and exclude them from control
 122          */
 123         bdgpio->gpio.ngpio = 4;
 124         bdgpio->regmap = dev_get_regmap(dev->parent, NULL);
 125         if (!bdgpio->regmap)
 126                 return -ENODEV;
 127
 128         return devm_gpiochip_add_data(dev, &bdgpio->gpio, bdgpio);
 129 }
 130
 131 static struct platform_driver bd71828_gpio = {
 132         .driver = {
 133                 .name = "bd71828-gpio"
 134         },
 135         .probe = bd71828_probe,
 136 };
 137
 138 module_platform_driver(bd71828_gpio);
 139
 140 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
 141 MODULE_DESCRIPTION("BD71828 voltage regulator driver");
 142 MODULE_LICENSE("GPL");
 143 MODULE_ALIAS("platform:bd71828-gpio");