From 03810031c91dfe448cd116ee987d5dc4139006f4 Mon Sep 17 00:00:00 2001 From: Emanuele Ghidoli Date: Mon, 13 Mar 2023 18:09:50 +0100 Subject: [PATCH] gpio: fxl6408: add I2C GPIO expander driver Add minimal driver for Fairchild FXL6408 8-bit I2C-controlled GPIO expander using the generic regmap based GPIO driver (GPIO_REGMAP). The driver implements setting the GPIO direction, reading inputs and writing outputs. In addition to that the FXL6408 has the following functionalities: - allows to monitor input ports for data transitions with an interrupt pin - all inputs can be configured with pull-up or pull-down resistors Datasheet: https://www.onsemi.com/download/data-sheet/pdf/fxl6408-d.pdf Signed-off-by: Emanuele Ghidoli Co-developed-by: Francesco Dolcini Signed-off-by: Francesco Dolcini Reviewed-by: Andy Shevchenko [Bartosz: order includes alphabetically] Signed-off-by: Bartosz Golaszewski --- drivers/gpio/Kconfig | 10 +++ drivers/gpio/Makefile | 1 + drivers/gpio/gpio-fxl6408.c | 158 ++++++++++++++++++++++++++++++++++++ 3 files changed, 169 insertions(+) create mode 100644 drivers/gpio/gpio-fxl6408.c diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 5ef2bfbd805b..68f58b0ba79f 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1007,6 +1007,16 @@ config GPIO_ADNP enough to represent all pins, but the driver will assume a register layout for 64 pins (8 registers). +config GPIO_FXL6408 + tristate "FXL6408 I2C GPIO expander" + select GPIO_REGMAP + select REGMAP_I2C + help + GPIO driver for Fairchild Semiconductor FXL6408 GPIO expander. + + To compile this driver as a module, choose M here: the module will + be called gpio-fxl6408. + config GPIO_GW_PLD tristate "Gateworks PLD GPIO Expander" depends on OF_GPIO diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 73d1ec260c14..4cdf400a9387 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -60,6 +60,7 @@ obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o obj-$(CONFIG_GPIO_EXAR) += gpio-exar.o obj-$(CONFIG_GPIO_F7188X) += gpio-f7188x.o obj-$(CONFIG_GPIO_FTGPIO010) += gpio-ftgpio010.o +obj-$(CONFIG_GPIO_FXL6408) += gpio-fxl6408.o obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o obj-$(CONFIG_GPIO_GPIO_MM) += gpio-gpio-mm.o obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o 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 + */ + +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_DESCRIPTION("FXL6408 GPIO driver"); +MODULE_LICENSE("GPL");