diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/gpio/gpio-xra1403.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-xra1403.c b/drivers/gpio/gpio-xra1403.c new file mode 100644 index 000000000..8711a7907 --- /dev/null +++ b/drivers/gpio/gpio-xra1403.c @@ -0,0 +1,238 @@ +/* + * 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"); |