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