drivers/gpio/gpio-fxl6408.c

Source file repositories/reference/linux-study-clean/drivers/gpio/gpio-fxl6408.c

File Facts

System
Linux kernel
Corpus path
drivers/gpio/gpio-fxl6408.c
Extension
.c
Size
4734 bytes
Lines
172
Domain
Driver Families
Bucket
drivers/gpio
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// 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_MAPLE,
	.num_reg_defaults_raw = FXL6408_REG_INT_STS + 1,
};

Annotation

Implementation Notes