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	gpio: add Technologic I2C-FPGA gpio support
This driver is generic and aims to support all Technologic Systems's boards embedding FPGA GPIOs with an I2C interface. This driver supports TS-4900, TS-7970, TS-7990 and TS-4100 series. Signed-off-by: Lucile Quirion <lucile.quirion@savoirfairelinux.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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					 3 changed files with 198 additions and 0 deletions
				
			
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			@ -777,6 +777,13 @@ config GPIO_TPIC2810
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	  To compile this driver as a module, choose M here: the module will
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	  be called gpio-tpic2810.
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config GPIO_TS4900
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	tristate "Technologic Systems FPGA I2C GPIO"
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	select REGMAP_I2C
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	help
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	  Say yes here to enabled the GPIO driver for Technologic's FPGA core.
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	  Series supported include TS-4100, TS-4900, TS-7970 and TS-7990.
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endmenu
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menu "MFD GPIO expanders"
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			@ -112,6 +112,7 @@ obj-$(CONFIG_GPIO_TPS6586X)	+= gpio-tps6586x.o
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obj-$(CONFIG_GPIO_TPS65910)	+= gpio-tps65910.o
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obj-$(CONFIG_GPIO_TPS65912)	+= gpio-tps65912.o
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obj-$(CONFIG_GPIO_TS4800)	+= gpio-ts4800.o
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obj-$(CONFIG_GPIO_TS4900)	+= gpio-ts4900.o
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obj-$(CONFIG_GPIO_TS5500)	+= gpio-ts5500.o
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obj-$(CONFIG_GPIO_TWL4030)	+= gpio-twl4030.o
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obj-$(CONFIG_GPIO_TWL6040)	+= gpio-twl6040.o
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										190
									
								
								drivers/gpio/gpio-ts4900.c
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										190
									
								
								drivers/gpio/gpio-ts4900.c
									
									
									
									
									
										Normal file
									
								
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			@ -0,0 +1,190 @@
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/*
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 * Digital I/O driver for Technologic Systems I2C FPGA Core
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 *
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 * Copyright (C) 2015 Technologic Systems
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 * Copyright (C) 2016 Savoir-Faire Linux
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public License version 2 as
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 * published by the Free Software Foundation.
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 *
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 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
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 * kind, whether expressed or implied; without even the implied warranty
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 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License version 2 for more details.
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 */
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#include <linux/gpio/driver.h>
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#include <linux/i2c.h>
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#include <linux/of_device.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#define DEFAULT_PIN_NUMBER	32
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/*
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 * Register bits used by the GPIO device
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 * Some boards, such as TS-7970 do not have a separate input bit
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 */
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#define TS4900_GPIO_OE		0x01
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#define TS4900_GPIO_OUT		0x02
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#define TS4900_GPIO_IN		0x04
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#define TS7970_GPIO_IN		0x02
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struct ts4900_gpio_priv {
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	struct regmap *regmap;
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	struct gpio_chip gpio_chip;
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	unsigned int input_bit;
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};
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static int ts4900_gpio_get_direction(struct gpio_chip *chip,
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				     unsigned int offset)
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{
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	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
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	unsigned int reg;
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	regmap_read(priv->regmap, offset, ®);
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	return !(reg & TS4900_GPIO_OE);
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}
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static int ts4900_gpio_direction_input(struct gpio_chip *chip,
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				       unsigned int offset)
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{
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	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
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	/*
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	 * This will clear the output enable bit, the other bits are
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	 * dontcare when this is cleared
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	 */
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	return regmap_write(priv->regmap, offset, 0);
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}
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static int ts4900_gpio_direction_output(struct gpio_chip *chip,
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					unsigned int offset, int value)
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{
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	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
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	int ret;
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	if (value)
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		ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE |
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							 TS4900_GPIO_OUT);
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	else
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		ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE);
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	return ret;
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}
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static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)
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{
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	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
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	unsigned int reg;
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	regmap_read(priv->regmap, offset, ®);
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	return !!(reg & priv->input_bit);
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}
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static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,
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			    int value)
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{
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	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
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	if (value)
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		regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT,
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				   TS4900_GPIO_OUT);
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	else
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		regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0);
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}
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static const struct regmap_config ts4900_regmap_config = {
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	.reg_bits = 16,
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	.val_bits = 8,
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};
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static struct gpio_chip template_chip = {
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	.label			= "ts4900-gpio",
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	.owner			= THIS_MODULE,
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	.get_direction		= ts4900_gpio_get_direction,
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	.direction_input	= ts4900_gpio_direction_input,
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	.direction_output	= ts4900_gpio_direction_output,
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	.get			= ts4900_gpio_get,
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	.set			= ts4900_gpio_set,
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	.base			= -1,
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	.can_sleep		= true,
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};
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static const struct of_device_id ts4900_gpio_of_match_table[] = {
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	{
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		.compatible = "technologic,ts4900-gpio",
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		.data = (void *)TS4900_GPIO_IN,
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	}, {
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		.compatible = "technologic,ts7970-gpio",
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		.data = (void *)TS7970_GPIO_IN,
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	},
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	{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table);
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static int ts4900_gpio_probe(struct i2c_client *client,
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			const struct i2c_device_id *id)
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{
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	const struct of_device_id *match;
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	struct ts4900_gpio_priv *priv;
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	u32 ngpio;
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	int ret;
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	match = of_match_device(ts4900_gpio_of_match_table, &client->dev);
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	if (!match)
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		return -EINVAL;
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	if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio))
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		ngpio = DEFAULT_PIN_NUMBER;
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	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
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	if (!priv)
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		return -ENOMEM;
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	priv->gpio_chip = template_chip;
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	priv->gpio_chip.label = "ts4900-gpio";
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	priv->gpio_chip.ngpio = ngpio;
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	priv->gpio_chip.parent = &client->dev;
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	priv->input_bit = (uintptr_t)match->data;
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	priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config);
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	if (IS_ERR(priv->regmap)) {
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		ret = PTR_ERR(priv->regmap);
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		dev_err(&client->dev, "Failed to allocate register map: %d\n",
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			ret);
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		return ret;
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	}
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	ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv);
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	if (ret < 0) {
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		dev_err(&client->dev, "Unable to register gpiochip\n");
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		return ret;
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	}
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	i2c_set_clientdata(client, priv);
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	return 0;
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}
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static const struct i2c_device_id ts4900_gpio_id_table[] = {
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	{ "ts4900-gpio", },
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	{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table);
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static struct i2c_driver ts4900_gpio_driver = {
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	.driver = {
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		.name = "ts4900-gpio",
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		.of_match_table = ts4900_gpio_of_match_table,
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	},
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	.probe = ts4900_gpio_probe,
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	.id_table = ts4900_gpio_id_table,
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};
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module_i2c_driver(ts4900_gpio_driver);
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MODULE_AUTHOR("Technologic Systems");
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MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core");
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MODULE_LICENSE("GPL");
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