--- /dev/null
+/*
+ * 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");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff