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
 13struct bd71828_gpio {
 14	struct regmap *regmap;
 15	struct device *dev;
 16	struct gpio_chip gpio;
 17};
 18
 19static 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
 39static 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
 57static 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
 82static 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
 98static 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
131static struct platform_driver bd71828_gpio = {
132	.driver = {
133		.name = "bd71828-gpio"
134	},
135	.probe = bd71828_probe,
136};
137
138module_platform_driver(bd71828_gpio);
139
140MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
141MODULE_DESCRIPTION("BD71828 voltage regulator driver");
142MODULE_LICENSE("GPL");
143MODULE_ALIAS("platform:bd71828-gpio");