--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (C) 2018 ROHM Semiconductors
+
+#include <linux/gpio/driver.h>
+#include <linux/mfd/rohm-bd71828.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define GPIO_OUT_REG(off) (BD71828_REG_GPIO_CTRL1 + (off))
+#define HALL_GPIO_OFFSET 3
+
+/*
+ * These defines can be removed when
+ * "gpio: Add definition for GPIO direction"
+ * (9208b1e77d6e8e9776f34f46ef4079ecac9c3c25 in GPIO tree) gets merged,
+ */
+#ifndef GPIO_LINE_DIRECTION_IN
+ #define GPIO_LINE_DIRECTION_IN 1
+ #define GPIO_LINE_DIRECTION_OUT 0
+#endif
+
+struct bd71828_gpio {
+ struct rohm_regmap_dev chip;
+ struct gpio_chip gpio;
+};
+
+static void bd71828_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ int ret;
+ struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
+ u8 val = (value) ? BD71828_GPIO_OUT_HI : BD71828_GPIO_OUT_LO;
+
+ /*
+ * The HALL input pin can only be used as input. If this is the pin
+ * we are dealing with - then we are done
+ */
+ if (offset == HALL_GPIO_OFFSET)
+ return;
+
+ ret = regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
+ BD71828_GPIO_OUT_MASK, val);
+ if (ret)
+ dev_err(bdgpio->chip.dev, "Could not set gpio to %d\n", value);
+}
+
+static int bd71828_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ int ret;
+ unsigned int val;
+ struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
+
+ if (offset == HALL_GPIO_OFFSET)
+ ret = regmap_read(bdgpio->chip.regmap, BD71828_REG_IO_STAT,
+ &val);
+ else
+ ret = regmap_read(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
+ &val);
+ if (!ret)
+ ret = (val & BD71828_GPIO_OUT_MASK);
+
+ return ret;
+}
+
+static int bd71828_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
+ unsigned long config)
+{
+ struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
+
+ if (offset == HALL_GPIO_OFFSET)
+ return -ENOTSUPP;
+
+ switch (pinconf_to_config_param(config)) {
+ case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+ return regmap_update_bits(bdgpio->chip.regmap,
+ GPIO_OUT_REG(offset),
+ BD71828_GPIO_DRIVE_MASK,
+ BD71828_GPIO_OPEN_DRAIN);
+ case PIN_CONFIG_DRIVE_PUSH_PULL:
+ return regmap_update_bits(bdgpio->chip.regmap,
+ GPIO_OUT_REG(offset),
+ BD71828_GPIO_DRIVE_MASK,
+ BD71828_GPIO_PUSH_PULL);
+ default:
+ break;
+ }
+ return -ENOTSUPP;
+}
+
+static int bd71828_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+ /*
+ * Pin usage is selected by OTP data. We can't read it runtime. Hence
+ * we trust that if the pin is not excluded by "gpio-reserved-ranges"
+ * the OTP configuration is set to OUT. (Other pins but HALL input pin
+ * on BD71828 can't really be used for general purpose input - input
+ * states are used for specific cases like regulator control or
+ * PMIC_ON_REQ.
+ */
+ if (offset == HALL_GPIO_OFFSET)
+ return GPIO_LINE_DIRECTION_IN;
+
+ return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int bd71828_probe(struct platform_device *pdev)
+{
+ struct bd71828_gpio *bdgpio;
+ struct rohm_regmap_dev *bd71828;
+
+ bd71828 = dev_get_drvdata(pdev->dev.parent);
+ if (!bd71828) {
+ dev_err(&pdev->dev, "No MFD driver data\n");
+ return -EINVAL;
+ }
+
+ bdgpio = devm_kzalloc(&pdev->dev, sizeof(*bdgpio),
+ GFP_KERNEL);
+ if (!bdgpio)
+ return -ENOMEM;
+
+ bdgpio->chip.dev = &pdev->dev;
+ bdgpio->gpio.parent = pdev->dev.parent;
+ bdgpio->gpio.label = "bd71828-gpio";
+ bdgpio->gpio.owner = THIS_MODULE;
+ bdgpio->gpio.get_direction = bd71828_get_direction;
+ bdgpio->gpio.set_config = bd71828_gpio_set_config;
+ bdgpio->gpio.can_sleep = true;
+ bdgpio->gpio.get = bd71828_gpio_get;
+ bdgpio->gpio.set = bd71828_gpio_set;
+ bdgpio->gpio.base = -1;
+
+ /*
+ * See if we need some implementation to mark some PINs as
+ * not controllable based on DT info or if core can handle
+ * "gpio-reserved-ranges" and exclude them from control
+ */
+ bdgpio->gpio.ngpio = 4;
+ bdgpio->gpio.of_node = pdev->dev.parent->of_node;
+ bdgpio->chip.regmap = bd71828->regmap;
+
+ return devm_gpiochip_add_data(&pdev->dev, &bdgpio->gpio,
+ bdgpio);
+}
+
+static struct platform_driver bd71828_gpio = {
+ .driver = {
+ .name = "bd71828-gpio"
+ },
+ .probe = bd71828_probe,
+};
+
+module_platform_driver(bd71828_gpio);
+
+MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
+MODULE_DESCRIPTION("BD71828 voltage regulator driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:bd71828-gpio");