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
 13struct bd71828_gpio {
 14	struct regmap *regmap;
 15	struct device *dev;
 16	struct gpio_chip gpio;
 17};
 18
 19static int bd71828_gpio_set(struct gpio_chip *chip, unsigned int offset,
 20			    int value)
 21{
 22	struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
 23	u8 val = (value) ? BD71828_GPIO_OUT_HI : BD71828_GPIO_OUT_LO;
 24
 25	/*
 26	 * The HALL input pin can only be used as input. If this is the pin
 27	 * we are dealing with - then we are done
 28	 */
 29	if (offset == HALL_GPIO_OFFSET)
 30		return 0;
 31
 32	return regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
 33				  BD71828_GPIO_OUT_MASK, val);
 34}
 35
 36static int bd71828_gpio_get(struct gpio_chip *chip, unsigned int offset)
 37{
 38	int ret;
 39	unsigned int val;
 40	struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
 41
 42	if (offset == HALL_GPIO_OFFSET)
 43		ret = regmap_read(bdgpio->regmap, BD71828_REG_IO_STAT,
 44				  &val);
 45	else
 46		ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset),
 47				  &val);
 48	if (!ret)
 49		ret = (val & BD71828_GPIO_OUT_MASK);
 50
 51	return ret;
 52}
 53
 54static int bd71828_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 55				   unsigned long config)
 56{
 57	struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
 58
 59	if (offset == HALL_GPIO_OFFSET)
 60		return -ENOTSUPP;
 61
 62	switch (pinconf_to_config_param(config)) {
 63	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
 64		return regmap_update_bits(bdgpio->regmap,
 65					  GPIO_OUT_REG(offset),
 66					  BD71828_GPIO_DRIVE_MASK,
 67					  BD71828_GPIO_OPEN_DRAIN);
 68	case PIN_CONFIG_DRIVE_PUSH_PULL:
 69		return regmap_update_bits(bdgpio->regmap,
 70					  GPIO_OUT_REG(offset),
 71					  BD71828_GPIO_DRIVE_MASK,
 72					  BD71828_GPIO_PUSH_PULL);
 73	default:
 74		break;
 75	}
 76	return -ENOTSUPP;
 77}
 78
 79static int bd71828_get_direction(struct gpio_chip *chip, unsigned int offset)
 80{
 81	/*
 82	 * Pin usage is selected by OTP data. We can't read it runtime. Hence
 83	 * we trust that if the pin is not excluded by "gpio-reserved-ranges"
 84	 * the OTP configuration is set to OUT. (Other pins but HALL input pin
 85	 * on BD71828 can't really be used for general purpose input - input
 86	 * states are used for specific cases like regulator control or
 87	 * PMIC_ON_REQ.
 88	 */
 89	if (offset == HALL_GPIO_OFFSET)
 90		return GPIO_LINE_DIRECTION_IN;
 91
 92	return GPIO_LINE_DIRECTION_OUT;
 93}
 94
 95static int bd71828_probe(struct platform_device *pdev)
 96{
 97	struct device *dev = &pdev->dev;
 98	struct bd71828_gpio *bdgpio;
 99
100	bdgpio = devm_kzalloc(dev, sizeof(*bdgpio), GFP_KERNEL);
101	if (!bdgpio)
102		return -ENOMEM;
103
104	bdgpio->dev = dev;
105	bdgpio->gpio.parent = dev->parent;
106	bdgpio->gpio.label = "bd71828-gpio";
107	bdgpio->gpio.owner = THIS_MODULE;
108	bdgpio->gpio.get_direction = bd71828_get_direction;
109	bdgpio->gpio.set_config = bd71828_gpio_set_config;
110	bdgpio->gpio.can_sleep = true;
111	bdgpio->gpio.get = bd71828_gpio_get;
112	bdgpio->gpio.set = bd71828_gpio_set;
113	bdgpio->gpio.base = -1;
114
115	/*
116	 * See if we need some implementation to mark some PINs as
117	 * not controllable based on DT info or if core can handle
118	 * "gpio-reserved-ranges" and exclude them from control
119	 */
120	bdgpio->gpio.ngpio = 4;
121	bdgpio->regmap = dev_get_regmap(dev->parent, NULL);
122	if (!bdgpio->regmap)
123		return -ENODEV;
124
125	return devm_gpiochip_add_data(dev, &bdgpio->gpio, bdgpio);
126}
127
128static struct platform_driver bd71828_gpio = {
129	.driver = {
130		.name = "bd71828-gpio"
131	},
132	.probe = bd71828_probe,
133};
134
135module_platform_driver(bd71828_gpio);
136
137MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
138MODULE_DESCRIPTION("BD71828 voltage regulator driver");
139MODULE_LICENSE("GPL");
140MODULE_ALIAS("platform:bd71828-gpio");