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Commit 5704520d authored by Nandor Han's avatar Nandor Han Committed by Linus Walleij
Browse files

gpio: xra1403: Add EXAR XRA1403 SPI GPIO expander driver 



This driver support basic XRA1403 functionalities:
    - set gpio direction
    - get gpio direction
    - set gpio high/low
    - get gpio status

Signed-off-by: default avatarNandor Han <nandor.han@ge.com>
Signed-off-by: default avatarSemi Malinen <semi.malinen@ge.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 7808c42b

drivers/gpio/Kconfig

+5 −0
Original line number Original line Diff line number Diff line
@@ -1225,6 +1225,11 @@ config GPIO_PISOSR 
	  GPIO driver for SPI compatible parallel-in/serial-out shift

	  GPIO driver for SPI compatible parallel-in/serial-out shift

	  registers. These are input only devices.

	  registers. These are input only devices.





config GPIO_XRA1403

	tristate "EXAR XRA1403 16-bit GPIO expander"

	help

	  GPIO driver for EXAR XRA1403 16-bit SPI-based GPIO expander.



endmenu

endmenu





menu "SPI or I2C GPIO expanders"

menu "SPI or I2C GPIO expanders"

drivers/gpio/Makefile

+1 −0
Original line number Original line Diff line number Diff line
@@ -141,6 +141,7 @@ obj-$(CONFIG_GPIO_XGENE) += gpio-xgene.o 
obj-$(CONFIG_GPIO_XGENE_SB)	+= gpio-xgene-sb.o

obj-$(CONFIG_GPIO_XGENE_SB)	+= gpio-xgene-sb.o

obj-$(CONFIG_GPIO_XILINX)	+= gpio-xilinx.o

obj-$(CONFIG_GPIO_XILINX)	+= gpio-xilinx.o

obj-$(CONFIG_GPIO_XLP)		+= gpio-xlp.o

obj-$(CONFIG_GPIO_XLP)		+= gpio-xlp.o

obj-$(CONFIG_GPIO_XRA1403)	+= gpio-xra1403.o

obj-$(CONFIG_GPIO_XTENSA)	+= gpio-xtensa.o

obj-$(CONFIG_GPIO_XTENSA)	+= gpio-xtensa.o

obj-$(CONFIG_GPIO_ZEVIO)	+= gpio-zevio.o

obj-$(CONFIG_GPIO_ZEVIO)	+= gpio-zevio.o

obj-$(CONFIG_GPIO_ZYNQ)		+= gpio-zynq.o

obj-$(CONFIG_GPIO_ZYNQ)		+= gpio-zynq.o

drivers/gpio/gpio-xra1403.c

0 → 100644
+237 −0
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/*

 * GPIO driver for EXAR XRA1403 16-bit GPIO expander

 *

 * Copyright (c) 2017, General Electric Company

 *

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

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/bitops.h>

#include <linux/gpio/driver.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of_device.h>

#include <linux/of_gpio.h>

#include <linux/seq_file.h>

#include <linux/spi/spi.h>

#include <linux/regmap.h>



/* XRA1403 registers */

#define XRA_GSR   0x00 /* GPIO State */

#define XRA_OCR   0x02 /* Output Control */

#define XRA_PIR   0x04 /* Input Polarity Inversion */

#define XRA_GCR   0x06 /* GPIO Configuration */

#define XRA_PUR   0x08 /* Input Internal Pull-up Resistor Enable/Disable */

#define XRA_IER   0x0A /* Input Interrupt Enable */

#define XRA_TSCR  0x0C /* Output Three-State Control */

#define XRA_ISR   0x0E /* Input Interrupt Status */

#define XRA_REIR  0x10 /* Input Rising Edge Interrupt Enable */

#define XRA_FEIR  0x12 /* Input Falling Edge Interrupt Enable */

#define XRA_IFR   0x14 /* Input Filter Enable/Disable */



struct xra1403 {

	struct gpio_chip  chip;

	struct regmap     *regmap;

};



static const struct regmap_config xra1403_regmap_cfg = {

		.reg_bits = 7,

		.pad_bits = 1,

		.val_bits = 8,



		.max_register = XRA_IFR | 0x01,

};



static unsigned int to_reg(unsigned int reg, unsigned int offset)

{

	return reg + (offset > 7);

}



static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)

{

	struct xra1403 *xra = gpiochip_get_data(chip);



	return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),

			BIT(offset % 8), BIT(offset % 8));

}



static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,

				    int value)

{

	int ret;

	struct xra1403 *xra = gpiochip_get_data(chip);



	ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),

			BIT(offset % 8), 0);

	if (ret)

		return ret;



	ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),

			BIT(offset % 8), value ? BIT(offset % 8) : 0);



	return ret;

}



static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)

{

	int ret;

	unsigned int val;

	struct xra1403 *xra = gpiochip_get_data(chip);



	ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);

	if (ret)

		return ret;



	return !!(val & BIT(offset % 8));

}



static int xra1403_get(struct gpio_chip *chip, unsigned int offset)

{

	int ret;

	unsigned int val;

	struct xra1403 *xra = gpiochip_get_data(chip);



	ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);

	if (ret)

		return ret;



	return !!(val & BIT(offset % 8));

}



static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)

{

	int ret;

	struct xra1403 *xra = gpiochip_get_data(chip);



	ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),

			BIT(offset % 8), value ? BIT(offset % 8) : 0);

	if (ret)

		dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",

				offset, ret);

}



#ifdef CONFIG_DEBUG_FS

static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)

{

	int reg;

	struct xra1403 *xra = gpiochip_get_data(chip);

	int value[xra1403_regmap_cfg.max_register];

	int i;

	unsigned int gcr;

	unsigned int gsr;



	seq_puts(s, "xra reg:");

	for (reg = 0; reg <= xra1403_regmap_cfg.max_register; reg++)

		seq_printf(s, " %2.2x", reg);

	seq_puts(s, "\n  value:");

	for (reg = 0; reg < xra1403_regmap_cfg.max_register; reg++) {

		regmap_read(xra->regmap, reg, &value[reg]);

		seq_printf(s, " %2.2x", value[reg]);

	}

	seq_puts(s, "\n");



	gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];

	gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];

	for (i = 0; i < chip->ngpio; i++) {

		const char *label = gpiochip_is_requested(chip, i);



		if (!label)

			continue;



		seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",

			   chip->base + i, label,

			   (gcr & BIT(i)) ? "in" : "out",

			   (gsr & BIT(i)) ? "hi" : "lo");

	}

}

#else

#define xra1403_dbg_show NULL

#endif



static int xra1403_probe(struct spi_device *spi)

{

	struct xra1403 *xra;

	struct gpio_desc *reset_gpio;

	int ret;



	xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);

	if (!xra)

		return -ENOMEM;



	/* bring the chip out of reset if reset pin is provided*/

	reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);

	if (IS_ERR(reset_gpio))

		dev_warn(&spi->dev, "Could not get reset-gpios\n");



	xra->chip.direction_input = xra1403_direction_input;

	xra->chip.direction_output = xra1403_direction_output;

	xra->chip.get_direction = xra1403_get_direction;

	xra->chip.get = xra1403_get;

	xra->chip.set = xra1403_set;



	xra->chip.dbg_show = xra1403_dbg_show;



	xra->chip.ngpio = 16;

	xra->chip.label = "xra1403";



	xra->chip.base = -1;

	xra->chip.can_sleep = true;

	xra->chip.parent = &spi->dev;

	xra->chip.owner = THIS_MODULE;



	xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);

	if (IS_ERR(xra->regmap)) {

		ret = PTR_ERR(xra->regmap);

		dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);

		return ret;

	}



	ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);

	if (ret < 0) {

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

		return ret;

	}



	spi_set_drvdata(spi, xra);



	return 0;

}



static const struct spi_device_id xra1403_ids[] = {

	{ "xra1403" },

	{},

};

MODULE_DEVICE_TABLE(spi, xra1403_ids);



static const struct of_device_id xra1403_spi_of_match[] = {

	{ .compatible = "exar,xra1403" },

	{},

};

MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);



static struct spi_driver xra1403_driver = {

	.probe    = xra1403_probe,

	.id_table = xra1403_ids,

	.driver   = {

		.name           = "xra1403",

		.of_match_table = of_match_ptr(xra1403_spi_of_match),

	},

};



module_spi_driver(xra1403_driver);



MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");

MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");

MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");

MODULE_LICENSE("GPL v2");