1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (C) 2018 ROHM Semiconductors
  3// gpio-bd70528.c ROHM BD70528MWV gpio driver
  4
  5#include <linux/gpio/driver.h>
  6#include <linux/mfd/rohm-bd70528.h>
  7#include <linux/module.h>
  8#include <linux/platform_device.h>
  9#include <linux/regmap.h>
 10
 11#define GPIO_IN_REG(offset) (BD70528_REG_GPIO1_IN + (offset) * 2)
 12#define GPIO_OUT_REG(offset) (BD70528_REG_GPIO1_OUT + (offset) * 2)
 13
 14struct bd70528_gpio {
 15	struct rohm_regmap_dev chip;
 16	struct gpio_chip gpio;
 17};
 18
 19static int bd70528_set_debounce(struct bd70528_gpio *bdgpio,
 20				unsigned int offset, unsigned int debounce)
 21{
 22	u8 val;
 23
 24	switch (debounce) {
 25	case 0:
 26		val = BD70528_DEBOUNCE_DISABLE;
 27		break;
 28	case 1 ... 15000:
 29		val = BD70528_DEBOUNCE_15MS;
 30		break;
 31	case 15001 ... 30000:
 32		val = BD70528_DEBOUNCE_30MS;
 33		break;
 34	case 30001 ... 50000:
 35		val = BD70528_DEBOUNCE_50MS;
 36		break;
 37	default:
 38		dev_err(bdgpio->chip.dev,
 39			"Invalid debounce value %u\n", debounce);
 40		return -EINVAL;
 41	}
 42	return regmap_update_bits(bdgpio->chip.regmap, GPIO_IN_REG(offset),
 43				 BD70528_DEBOUNCE_MASK, val);
 44}
 45
 46static int bd70528_get_direction(struct gpio_chip *chip, unsigned int offset)
 47{
 48	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
 49	int val, ret;
 50
 51	/* Do we need to do something to IRQs here? */
 52	ret = regmap_read(bdgpio->chip.regmap, GPIO_OUT_REG(offset), &val);
 53	if (ret) {
 54		dev_err(bdgpio->chip.dev, "Could not read gpio direction\n");
 55		return ret;
 56	}
 57
 58	return !(val & BD70528_GPIO_OUT_EN_MASK);
 59}
 60
 61static int bd70528_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 62				   unsigned long config)
 63{
 64	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
 65
 66	switch (pinconf_to_config_param(config)) {
 67	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
 68		return regmap_update_bits(bdgpio->chip.regmap,
 69					  GPIO_OUT_REG(offset),
 70					  BD70528_GPIO_DRIVE_MASK,
 71					  BD70528_GPIO_OPEN_DRAIN);
 72		break;
 73	case PIN_CONFIG_DRIVE_PUSH_PULL:
 74		return regmap_update_bits(bdgpio->chip.regmap,
 75					  GPIO_OUT_REG(offset),
 76					  BD70528_GPIO_DRIVE_MASK,
 77					  BD70528_GPIO_PUSH_PULL);
 78		break;
 79	case PIN_CONFIG_INPUT_DEBOUNCE:
 80		return bd70528_set_debounce(bdgpio, offset,
 81					    pinconf_to_config_argument(config));
 82		break;
 83	default:
 84		break;
 85	}
 86	return -ENOTSUPP;
 87}
 88
 89static int bd70528_direction_input(struct gpio_chip *chip, unsigned int offset)
 90{
 91	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
 92
 93	/* Do we need to do something to IRQs here? */
 94	return regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
 95				 BD70528_GPIO_OUT_EN_MASK,
 96				 BD70528_GPIO_OUT_DISABLE);
 97}
 98
 99static void bd70528_gpio_set(struct gpio_chip *chip, unsigned int offset,
100			     int value)
101{
102	int ret;
103	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
104	u8 val = (value) ? BD70528_GPIO_OUT_HI : BD70528_GPIO_OUT_LO;
105
106	ret = regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
107				 BD70528_GPIO_OUT_MASK, val);
108	if (ret)
109		dev_err(bdgpio->chip.dev, "Could not set gpio to %d\n", value);
110}
111
112static int bd70528_direction_output(struct gpio_chip *chip, unsigned int offset,
113				    int value)
114{
115	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
116
117	bd70528_gpio_set(chip, offset, value);
118	return regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
119				 BD70528_GPIO_OUT_EN_MASK,
120				 BD70528_GPIO_OUT_ENABLE);
121}
122
123#define GPIO_IN_STATE_MASK(offset) (BD70528_GPIO_IN_STATE_BASE << (offset))
124
125static int bd70528_gpio_get_o(struct bd70528_gpio *bdgpio, unsigned int offset)
126{
127	int ret;
128	unsigned int val;
129
130	ret = regmap_read(bdgpio->chip.regmap, GPIO_OUT_REG(offset), &val);
131	if (!ret)
132		ret = !!(val & BD70528_GPIO_OUT_MASK);
133	else
134		dev_err(bdgpio->chip.dev, "GPIO (out) state read failed\n");
135
136	return ret;
137}
138
139static int bd70528_gpio_get_i(struct bd70528_gpio *bdgpio, unsigned int offset)
140{
141	unsigned int val;
142	int ret;
143
144	ret = regmap_read(bdgpio->chip.regmap, BD70528_REG_GPIO_STATE, &val);
145
146	if (!ret)
147		ret = !(val & GPIO_IN_STATE_MASK(offset));
148	else
149		dev_err(bdgpio->chip.dev, "GPIO (in) state read failed\n");
150
151	return ret;
152}
153
154static int bd70528_gpio_get(struct gpio_chip *chip, unsigned int offset)
155{
156	int ret;
157	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
158
159	/*
160	 * There is a race condition where someone might be changing the
161	 * GPIO direction after we get it but before we read the value. But
162	 * application design where GPIO direction may be changed just when
163	 * we read GPIO value would be pointless as reader could not know
164	 * whether the returned high/low state is caused by input or output.
165	 * Or then there must be other ways to mitigate the issue. Thus
166	 * locking would make no sense.
167	 */
168	ret = bd70528_get_direction(chip, offset);
169	if (ret == 0)
170		ret = bd70528_gpio_get_o(bdgpio, offset);
171	else if (ret == 1)
172		ret = bd70528_gpio_get_i(bdgpio, offset);
173	else
174		dev_err(bdgpio->chip.dev, "failed to read GPIO direction\n");
175
176	return ret;
177}
178
179static int bd70528_probe(struct platform_device *pdev)
180{
181	struct bd70528_gpio *bdgpio;
182	struct rohm_regmap_dev *bd70528;
183	int ret;
184
185	bd70528 = dev_get_drvdata(pdev->dev.parent);
186	if (!bd70528) {
187		dev_err(&pdev->dev, "No MFD driver data\n");
188		return -EINVAL;
189	}
190
191	bdgpio = devm_kzalloc(&pdev->dev, sizeof(*bdgpio),
192			      GFP_KERNEL);
193	if (!bdgpio)
194		return -ENOMEM;
195	bdgpio->chip.dev = &pdev->dev;
196	bdgpio->gpio.parent = pdev->dev.parent;
197	bdgpio->gpio.label = "bd70528-gpio";
198	bdgpio->gpio.owner = THIS_MODULE;
199	bdgpio->gpio.get_direction = bd70528_get_direction;
200	bdgpio->gpio.direction_input = bd70528_direction_input;
201	bdgpio->gpio.direction_output = bd70528_direction_output;
202	bdgpio->gpio.set_config = bd70528_gpio_set_config;
203	bdgpio->gpio.can_sleep = true;
204	bdgpio->gpio.get = bd70528_gpio_get;
205	bdgpio->gpio.set = bd70528_gpio_set;
206	bdgpio->gpio.ngpio = 4;
207	bdgpio->gpio.base = -1;
208#ifdef CONFIG_OF_GPIO
209	bdgpio->gpio.of_node = pdev->dev.parent->of_node;
210#endif
211	bdgpio->chip.regmap = bd70528->regmap;
212
213	ret = devm_gpiochip_add_data(&pdev->dev, &bdgpio->gpio,
214				     bdgpio);
215	if (ret)
216		dev_err(&pdev->dev, "gpio_init: Failed to add bd70528-gpio\n");
217
218	return ret;
219}
220
221static struct platform_driver bd70528_gpio = {
222	.driver = {
223		.name = "bd70528-gpio"
224	},
225	.probe = bd70528_probe,
226};
227
228module_platform_driver(bd70528_gpio);
229
230MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
231MODULE_DESCRIPTION("BD70528 voltage regulator driver");
232MODULE_LICENSE("GPL");