1 // SPDX-License-Identifier: GPL-2.0
3 * Digital I/O driver for Technologic Systems I2C FPGA Core
5 * Copyright (C) 2015, 2018 Technologic Systems
6 * Copyright (C) 2016 Savoir-Faire Linux
9 #include <linux/gpio/driver.h>
10 #include <linux/i2c.h>
11 #include <linux/of_device.h>
12 #include <linux/module.h>
13 #include <linux/regmap.h>
15 #define DEFAULT_PIN_NUMBER 32
17 * Register bits used by the GPIO device
18 * Some boards, such as TS-7970 do not have a separate input bit
20 #define TS4900_GPIO_OE 0x01
21 #define TS4900_GPIO_OUT 0x02
22 #define TS4900_GPIO_IN 0x04
23 #define TS7970_GPIO_IN 0x02
25 struct ts4900_gpio_priv {
26 struct regmap *regmap;
27 struct gpio_chip gpio_chip;
28 unsigned int input_bit;
31 static int ts4900_gpio_get_direction(struct gpio_chip *chip,
34 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
37 regmap_read(priv->regmap, offset, ®);
39 if (reg & TS4900_GPIO_OE)
40 return GPIO_LINE_DIRECTION_OUT;
42 return GPIO_LINE_DIRECTION_IN;
45 static int ts4900_gpio_direction_input(struct gpio_chip *chip,
48 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
50 /* Only clear the OE bit here, requires a RMW. Prevents potential issue
51 * with OE and data getting to the physical pin at different times.
53 return regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OE, 0);
56 static int ts4900_gpio_direction_output(struct gpio_chip *chip,
57 unsigned int offset, int value)
59 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
63 /* If changing from an input to an output, we need to first set the
64 * proper data bit to what is requested and then set OE bit. This
65 * prevents a glitch that can occur on the IO line
67 regmap_read(priv->regmap, offset, ®);
68 if (!(reg & TS4900_GPIO_OE)) {
70 reg = TS4900_GPIO_OUT;
72 reg &= ~TS4900_GPIO_OUT;
74 regmap_write(priv->regmap, offset, reg);
78 ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE |
81 ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE);
86 static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)
88 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
91 regmap_read(priv->regmap, offset, ®);
93 return !!(reg & priv->input_bit);
96 static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,
99 struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
102 regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT,
105 regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0);
108 static const struct regmap_config ts4900_regmap_config = {
113 static const struct gpio_chip template_chip = {
114 .label = "ts4900-gpio",
115 .owner = THIS_MODULE,
116 .get_direction = ts4900_gpio_get_direction,
117 .direction_input = ts4900_gpio_direction_input,
118 .direction_output = ts4900_gpio_direction_output,
119 .get = ts4900_gpio_get,
120 .set = ts4900_gpio_set,
125 static const struct of_device_id ts4900_gpio_of_match_table[] = {
127 .compatible = "technologic,ts4900-gpio",
128 .data = (void *)TS4900_GPIO_IN,
130 .compatible = "technologic,ts7970-gpio",
131 .data = (void *)TS7970_GPIO_IN,
135 MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table);
137 static int ts4900_gpio_probe(struct i2c_client *client,
138 const struct i2c_device_id *id)
140 struct ts4900_gpio_priv *priv;
144 if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio))
145 ngpio = DEFAULT_PIN_NUMBER;
147 priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
151 priv->gpio_chip = template_chip;
152 priv->gpio_chip.label = "ts4900-gpio";
153 priv->gpio_chip.ngpio = ngpio;
154 priv->gpio_chip.parent = &client->dev;
155 priv->input_bit = (uintptr_t)of_device_get_match_data(&client->dev);
157 priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config);
158 if (IS_ERR(priv->regmap)) {
159 ret = PTR_ERR(priv->regmap);
160 dev_err(&client->dev, "Failed to allocate register map: %d\n",
165 ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv);
167 dev_err(&client->dev, "Unable to register gpiochip\n");
171 i2c_set_clientdata(client, priv);
176 static const struct i2c_device_id ts4900_gpio_id_table[] = {
180 MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table);
182 static struct i2c_driver ts4900_gpio_driver = {
184 .name = "ts4900-gpio",
185 .of_match_table = ts4900_gpio_of_match_table,
187 .probe = ts4900_gpio_probe,
188 .id_table = ts4900_gpio_id_table,
190 module_i2c_driver(ts4900_gpio_driver);
192 MODULE_AUTHOR("Technologic Systems");
193 MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core");
194 MODULE_LICENSE("GPL");