diff options
Diffstat (limited to 'drivers/gpio/gpio-fxl6408.c')
| -rw-r--r-- | drivers/gpio/gpio-fxl6408.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-fxl6408.c b/drivers/gpio/gpio-fxl6408.c new file mode 100644 index 000000000000..208fa851e82a --- /dev/null +++ b/drivers/gpio/gpio-fxl6408.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * FXL6408 GPIO driver + * + * Copyright 2023 Toradex + * + * Author: Emanuele Ghidoli <emanuele.ghidoli@toradex.com> + */ + +#include <linux/err.h> +#include <linux/gpio/regmap.h> +#include <linux/i2c.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/regmap.h> + +#define FXL6408_REG_DEVICE_ID 0x01 +#define FXL6408_MF_FAIRCHILD 0b101 +#define FXL6408_MF_SHIFT 5 + +/* Bits set here indicate that the GPIO is an output. */ +#define FXL6408_REG_IO_DIR 0x03 + +/* + * Bits set here, when the corresponding bit of IO_DIR is set, drive + * the output high instead of low. + */ +#define FXL6408_REG_OUTPUT 0x05 + +/* Bits here make the output High-Z, instead of the OUTPUT value. */ +#define FXL6408_REG_OUTPUT_HIGH_Z 0x07 + +/* Returns the current status (1 = HIGH) of the input pins. */ +#define FXL6408_REG_INPUT_STATUS 0x0f + +/* + * Return the current interrupt status + * This bit is HIGH if input GPIO != default state (register 09h). + * The flag is cleared after being read (bit returns to 0). + * The input must go back to default state and change again before this flag is raised again. + */ +#define FXL6408_REG_INT_STS 0x13 + +#define FXL6408_NGPIO 8 + +static const struct regmap_range rd_range[] = { + { FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID }, + { FXL6408_REG_IO_DIR, FXL6408_REG_OUTPUT }, + { FXL6408_REG_INPUT_STATUS, FXL6408_REG_INPUT_STATUS }, +}; + +static const struct regmap_range wr_range[] = { + { FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID }, + { FXL6408_REG_IO_DIR, FXL6408_REG_OUTPUT }, + { FXL6408_REG_OUTPUT_HIGH_Z, FXL6408_REG_OUTPUT_HIGH_Z }, +}; + +static const struct regmap_range volatile_range[] = { + { FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID }, + { FXL6408_REG_INPUT_STATUS, FXL6408_REG_INPUT_STATUS }, +}; + +static const struct regmap_access_table rd_table = { + .yes_ranges = rd_range, + .n_yes_ranges = ARRAY_SIZE(rd_range), +}; + +static const struct regmap_access_table wr_table = { + .yes_ranges = wr_range, + .n_yes_ranges = ARRAY_SIZE(wr_range), +}; + +static const struct regmap_access_table volatile_table = { + .yes_ranges = volatile_range, + .n_yes_ranges = ARRAY_SIZE(volatile_range), +}; + +static const struct regmap_config regmap = { + .reg_bits = 8, + .val_bits = 8, + + .max_register = FXL6408_REG_INT_STS, + .wr_table = &wr_table, + .rd_table = &rd_table, + .volatile_table = &volatile_table, + + .cache_type = REGCACHE_RBTREE, + .num_reg_defaults_raw = FXL6408_REG_INT_STS + 1, +}; + +static int fxl6408_identify(struct device *dev, struct regmap *regmap) +{ + int val, ret; + + ret = regmap_read(regmap, FXL6408_REG_DEVICE_ID, &val); + if (ret) + return dev_err_probe(dev, ret, "error reading DEVICE_ID\n"); + if (val >> FXL6408_MF_SHIFT != FXL6408_MF_FAIRCHILD) + return dev_err_probe(dev, -ENODEV, "invalid device id 0x%02x\n", val); + + return 0; +} + +static int fxl6408_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + int ret; + struct gpio_regmap_config gpio_config = { + .parent = dev, + .ngpio = FXL6408_NGPIO, + .reg_dat_base = GPIO_REGMAP_ADDR(FXL6408_REG_INPUT_STATUS), + .reg_set_base = GPIO_REGMAP_ADDR(FXL6408_REG_OUTPUT), + .reg_dir_out_base = GPIO_REGMAP_ADDR(FXL6408_REG_IO_DIR), + .ngpio_per_reg = FXL6408_NGPIO, + }; + + gpio_config.regmap = devm_regmap_init_i2c(client, ®map); + if (IS_ERR(gpio_config.regmap)) + return dev_err_probe(dev, PTR_ERR(gpio_config.regmap), + "failed to allocate register map\n"); + + ret = fxl6408_identify(dev, gpio_config.regmap); + if (ret) + return ret; + + /* Disable High-Z of outputs, so that our OUTPUT updates actually take effect. */ + ret = regmap_write(gpio_config.regmap, FXL6408_REG_OUTPUT_HIGH_Z, 0); + if (ret) + return dev_err_probe(dev, ret, "failed to write 'output high Z' register\n"); + + return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config)); +} + +static const __maybe_unused struct of_device_id fxl6408_dt_ids[] = { + { .compatible = "fcs,fxl6408" }, + { } +}; +MODULE_DEVICE_TABLE(of, fxl6408_dt_ids); + +static const struct i2c_device_id fxl6408_id[] = { + { "fxl6408", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, fxl6408_id); + +static struct i2c_driver fxl6408_driver = { + .driver = { + .name = "fxl6408", + .of_match_table = fxl6408_dt_ids, + }, + .probe_new = fxl6408_probe, + .id_table = fxl6408_id, +}; +module_i2c_driver(fxl6408_driver); + +MODULE_AUTHOR("Emanuele Ghidoli <emanuele.ghidoli@toradex.com>"); +MODULE_DESCRIPTION("FXL6408 GPIO driver"); +MODULE_LICENSE("GPL"); |