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	if (val & BD70528_GPIO_OUT_EN_MASK)
 58		return GPIO_LINE_DIRECTION_OUT;
 59
 60	return GPIO_LINE_DIRECTION_IN;
 61}
 62
 63static int bd70528_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 64				   unsigned long config)
 65{
 66	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
 67
 68	switch (pinconf_to_config_param(config)) {
 69	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
 70		return regmap_update_bits(bdgpio->chip.regmap,
 71					  GPIO_OUT_REG(offset),
 72					  BD70528_GPIO_DRIVE_MASK,
 73					  BD70528_GPIO_OPEN_DRAIN);
 74		break;
 75	case PIN_CONFIG_DRIVE_PUSH_PULL:
 76		return regmap_update_bits(bdgpio->chip.regmap,
 77					  GPIO_OUT_REG(offset),
 78					  BD70528_GPIO_DRIVE_MASK,
 79					  BD70528_GPIO_PUSH_PULL);
 80		break;
 81	case PIN_CONFIG_INPUT_DEBOUNCE:
 82		return bd70528_set_debounce(bdgpio, offset,
 83					    pinconf_to_config_argument(config));
 84		break;
 85	default:
 86		break;
 87	}
 88	return -ENOTSUPP;
 89}
 90
 91static int bd70528_direction_input(struct gpio_chip *chip, unsigned int offset)
 92{
 93	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
 94
 95	/* Do we need to do something to IRQs here? */
 96	return regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
 97				 BD70528_GPIO_OUT_EN_MASK,
 98				 BD70528_GPIO_OUT_DISABLE);
 99}
100
101static void bd70528_gpio_set(struct gpio_chip *chip, unsigned int offset,
102			     int value)
103{
104	int ret;
105	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
106	u8 val = (value) ? BD70528_GPIO_OUT_HI : BD70528_GPIO_OUT_LO;
107
108	ret = regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
109				 BD70528_GPIO_OUT_MASK, val);
110	if (ret)
111		dev_err(bdgpio->chip.dev, "Could not set gpio to %d\n", value);
112}
113
114static int bd70528_direction_output(struct gpio_chip *chip, unsigned int offset,
115				    int value)
116{
117	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
118
119	bd70528_gpio_set(chip, offset, value);
120	return regmap_update_bits(bdgpio->chip.regmap, GPIO_OUT_REG(offset),
121				 BD70528_GPIO_OUT_EN_MASK,
122				 BD70528_GPIO_OUT_ENABLE);
123}
124
125#define GPIO_IN_STATE_MASK(offset) (BD70528_GPIO_IN_STATE_BASE << (offset))
126
127static int bd70528_gpio_get_o(struct bd70528_gpio *bdgpio, unsigned int offset)
128{
129	int ret;
130	unsigned int val;
131
132	ret = regmap_read(bdgpio->chip.regmap, GPIO_OUT_REG(offset), &val);
133	if (!ret)
134		ret = !!(val & BD70528_GPIO_OUT_MASK);
135	else
136		dev_err(bdgpio->chip.dev, "GPIO (out) state read failed\n");
137
138	return ret;
139}
140
141static int bd70528_gpio_get_i(struct bd70528_gpio *bdgpio, unsigned int offset)
142{
143	unsigned int val;
144	int ret;
145
146	ret = regmap_read(bdgpio->chip.regmap, BD70528_REG_GPIO_STATE, &val);
147
148	if (!ret)
149		ret = !(val & GPIO_IN_STATE_MASK(offset));
150	else
151		dev_err(bdgpio->chip.dev, "GPIO (in) state read failed\n");
152
153	return ret;
154}
155
156static int bd70528_gpio_get(struct gpio_chip *chip, unsigned int offset)
157{
158	int ret;
159	struct bd70528_gpio *bdgpio = gpiochip_get_data(chip);
160
161	/*
162	 * There is a race condition where someone might be changing the
163	 * GPIO direction after we get it but before we read the value. But
164	 * application design where GPIO direction may be changed just when
165	 * we read GPIO value would be pointless as reader could not know
166	 * whether the returned high/low state is caused by input or output.
167	 * Or then there must be other ways to mitigate the issue. Thus
168	 * locking would make no sense.
169	 */
170	ret = bd70528_get_direction(chip, offset);
171	if (ret == GPIO_LINE_DIRECTION_OUT)
172		ret = bd70528_gpio_get_o(bdgpio, offset);
173	else if (ret == GPIO_LINE_DIRECTION_IN)
174		ret = bd70528_gpio_get_i(bdgpio, offset);
175	else
176		dev_err(bdgpio->chip.dev, "failed to read GPIO direction\n");
177
178	return ret;
179}
180
181static int bd70528_probe(struct platform_device *pdev)
182{
183	struct bd70528_gpio *bdgpio;
184	struct rohm_regmap_dev *bd70528;
185	int ret;
186
187	bd70528 = dev_get_drvdata(pdev->dev.parent);
188	if (!bd70528) {
189		dev_err(&pdev->dev, "No MFD driver data\n");
190		return -EINVAL;
191	}
192
193	bdgpio = devm_kzalloc(&pdev->dev, sizeof(*bdgpio),
194			      GFP_KERNEL);
195	if (!bdgpio)
196		return -ENOMEM;
197	bdgpio->chip.dev = &pdev->dev;
198	bdgpio->gpio.parent = pdev->dev.parent;
199	bdgpio->gpio.label = "bd70528-gpio";
200	bdgpio->gpio.owner = THIS_MODULE;
201	bdgpio->gpio.get_direction = bd70528_get_direction;
202	bdgpio->gpio.direction_input = bd70528_direction_input;
203	bdgpio->gpio.direction_output = bd70528_direction_output;
204	bdgpio->gpio.set_config = bd70528_gpio_set_config;
205	bdgpio->gpio.can_sleep = true;
206	bdgpio->gpio.get = bd70528_gpio_get;
207	bdgpio->gpio.set = bd70528_gpio_set;
208	bdgpio->gpio.ngpio = 4;
209	bdgpio->gpio.base = -1;
210#ifdef CONFIG_OF_GPIO
211	bdgpio->gpio.of_node = pdev->dev.parent->of_node;
212#endif
213	bdgpio->chip.regmap = bd70528->regmap;
214
215	ret = devm_gpiochip_add_data(&pdev->dev, &bdgpio->gpio,
216				     bdgpio);
217	if (ret)
218		dev_err(&pdev->dev, "gpio_init: Failed to add bd70528-gpio\n");
219
220	return ret;
221}
222
223static struct platform_driver bd70528_gpio = {
224	.driver = {
225		.name = "bd70528-gpio"
226	},
227	.probe = bd70528_probe,
228};
229
230module_platform_driver(bd70528_gpio);
231
232MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
233MODULE_DESCRIPTION("BD70528 voltage regulator driver");
234MODULE_LICENSE("GPL");
235MODULE_ALIAS("platform:bd70528-gpio");