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Commit 9c668632 authored by Lucile Quirion's avatar Lucile Quirion Committed by Linus Walleij
Browse files

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: default avatarLucile Quirion <lucile.quirion@savoirfairelinux.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 4cebaf17

drivers/gpio/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -777,6 +777,13 @@ config GPIO_TPIC2810 
	  To compile this driver as a module, choose M here: the module will

	  be called gpio-tpic2810.



config GPIO_TS4900

	tristate "Technologic Systems FPGA I2C GPIO"

	select REGMAP_I2C

	help

	  Say yes here to enabled the GPIO driver for Technologic's FPGA core.

	  Series supported include TS-4100, TS-4900, TS-7970 and TS-7990.



endmenu



menu "MFD GPIO expanders"

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ obj-$(CONFIG_GPIO_TPS6586X) += gpio-tps6586x.o 
obj-$(CONFIG_GPIO_TPS65910)	+= gpio-tps65910.o

obj-$(CONFIG_GPIO_TPS65912)	+= gpio-tps65912.o

obj-$(CONFIG_GPIO_TS4800)	+= gpio-ts4800.o

obj-$(CONFIG_GPIO_TS4900)	+= gpio-ts4900.o

obj-$(CONFIG_GPIO_TS5500)	+= gpio-ts5500.o

obj-$(CONFIG_GPIO_TWL4030)	+= gpio-twl4030.o

obj-$(CONFIG_GPIO_TWL6040)	+= gpio-twl6040.o

drivers/gpio/gpio-ts4900.c

0 → 100644
+190 −0
Original line number Diff line number Diff line 
/*

 * Digital I/O driver for Technologic Systems I2C FPGA Core

 *

 * Copyright (C) 2015 Technologic Systems

 * Copyright (C) 2016 Savoir-Faire Linux

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether expressed or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License version 2 for more details.

 */



#include <linux/gpio/driver.h>

#include <linux/i2c.h>

#include <linux/of_device.h>

#include <linux/module.h>

#include <linux/regmap.h>



#define DEFAULT_PIN_NUMBER	32

/*

 * Register bits used by the GPIO device

 * Some boards, such as TS-7970 do not have a separate input bit

 */

#define TS4900_GPIO_OE		0x01

#define TS4900_GPIO_OUT		0x02

#define TS4900_GPIO_IN		0x04

#define TS7970_GPIO_IN		0x02



struct ts4900_gpio_priv {

	struct regmap *regmap;

	struct gpio_chip gpio_chip;

	unsigned int input_bit;

};



static int ts4900_gpio_get_direction(struct gpio_chip *chip,

				     unsigned int offset)

{

	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);

	unsigned int reg;



	regmap_read(priv->regmap, offset, &reg);



	return !(reg & TS4900_GPIO_OE);

}



static int ts4900_gpio_direction_input(struct gpio_chip *chip,

				       unsigned int offset)

{

	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);



	/*

	 * This will clear the output enable bit, the other bits are

	 * dontcare when this is cleared

	 */

	return regmap_write(priv->regmap, offset, 0);

}



static int ts4900_gpio_direction_output(struct gpio_chip *chip,

					unsigned int offset, int value)

{

	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);

	int ret;



	if (value)

		ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE |

							 TS4900_GPIO_OUT);

	else

		ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE);



	return ret;

}



static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)

{

	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);

	unsigned int reg;



	regmap_read(priv->regmap, offset, &reg);



	return !!(reg & priv->input_bit);

}



static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,

			    int value)

{

	struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);



	if (value)

		regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT,

				   TS4900_GPIO_OUT);

	else

		regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0);

}



static const struct regmap_config ts4900_regmap_config = {

	.reg_bits = 16,

	.val_bits = 8,

};



static struct gpio_chip template_chip = {

	.label			= "ts4900-gpio",

	.owner			= THIS_MODULE,

	.get_direction		= ts4900_gpio_get_direction,

	.direction_input	= ts4900_gpio_direction_input,

	.direction_output	= ts4900_gpio_direction_output,

	.get			= ts4900_gpio_get,

	.set			= ts4900_gpio_set,

	.base			= -1,

	.can_sleep		= true,

};



static const struct of_device_id ts4900_gpio_of_match_table[] = {

	{

		.compatible = "technologic,ts4900-gpio",

		.data = (void *)TS4900_GPIO_IN,

	}, {

		.compatible = "technologic,ts7970-gpio",

		.data = (void *)TS7970_GPIO_IN,

	},

	{ /* sentinel */ },

};

MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table);



static int ts4900_gpio_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	const struct of_device_id *match;

	struct ts4900_gpio_priv *priv;

	u32 ngpio;

	int ret;



	match = of_match_device(ts4900_gpio_of_match_table, &client->dev);

	if (!match)

		return -EINVAL;



	if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio))

		ngpio = DEFAULT_PIN_NUMBER;



	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	priv->gpio_chip = template_chip;

	priv->gpio_chip.label = "ts4900-gpio";

	priv->gpio_chip.ngpio = ngpio;

	priv->gpio_chip.parent = &client->dev;

	priv->input_bit = (uintptr_t)match->data;



	priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config);

	if (IS_ERR(priv->regmap)) {

		ret = PTR_ERR(priv->regmap);

		dev_err(&client->dev, "Failed to allocate register map: %d\n",

			ret);

		return ret;

	}



	ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv);

	if (ret < 0) {

		dev_err(&client->dev, "Unable to register gpiochip\n");

		return ret;

	}



	i2c_set_clientdata(client, priv);



	return 0;

}



static const struct i2c_device_id ts4900_gpio_id_table[] = {

	{ "ts4900-gpio", },

	{ /* sentinel */ }

};

MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table);



static struct i2c_driver ts4900_gpio_driver = {

	.driver = {

		.name = "ts4900-gpio",

		.of_match_table = ts4900_gpio_of_match_table,

	},

	.probe = ts4900_gpio_probe,

	.id_table = ts4900_gpio_id_table,

};

module_i2c_driver(ts4900_gpio_driver);



MODULE_AUTHOR("Technologic Systems");

MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core");

MODULE_LICENSE("GPL");