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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 */
#define XRA_LAST 0x15 /* Bounds */
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_LAST,
};
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[XRA_LAST];
int i;
unsigned int gcr;
unsigned int gsr;
seq_puts(s, "xra reg:");
for (reg = 0; reg <= XRA_LAST; reg++)
seq_printf(s, " %2.2x", reg);
seq_puts(s, "\n value:");
for (reg = 0; reg < XRA_LAST; 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");
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