159 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * FXL6408 GPIO driver4 *5 * Copyright 2023 Toradex6 *7 * Author: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>8 */9 10#include <linux/err.h>11#include <linux/gpio/regmap.h>12#include <linux/i2c.h>13#include <linux/kernel.h>14#include <linux/module.h>15#include <linux/regmap.h>16 17#define FXL6408_REG_DEVICE_ID 0x0118#define FXL6408_MF_FAIRCHILD 0b10119#define FXL6408_MF_SHIFT 520 21/* Bits set here indicate that the GPIO is an output. */22#define FXL6408_REG_IO_DIR 0x0323 24/*25 * Bits set here, when the corresponding bit of IO_DIR is set, drive26 * the output high instead of low.27 */28#define FXL6408_REG_OUTPUT 0x0529 30/* Bits here make the output High-Z, instead of the OUTPUT value. */31#define FXL6408_REG_OUTPUT_HIGH_Z 0x0732 33/* Returns the current status (1 = HIGH) of the input pins. */34#define FXL6408_REG_INPUT_STATUS 0x0f35 36/*37 * Return the current interrupt status38 * This bit is HIGH if input GPIO != default state (register 09h).39 * The flag is cleared after being read (bit returns to 0).40 * The input must go back to default state and change again before this flag is raised again.41 */42#define FXL6408_REG_INT_STS 0x1343 44#define FXL6408_NGPIO 845 46static const struct regmap_range rd_range[] = {47 { FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID },48 { FXL6408_REG_IO_DIR, FXL6408_REG_OUTPUT },49 { FXL6408_REG_INPUT_STATUS, FXL6408_REG_INPUT_STATUS },50};51 52static const struct regmap_range wr_range[] = {53 { FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID },54 { FXL6408_REG_IO_DIR, FXL6408_REG_OUTPUT },55 { FXL6408_REG_OUTPUT_HIGH_Z, FXL6408_REG_OUTPUT_HIGH_Z },56};57 58static const struct regmap_range volatile_range[] = {59 { FXL6408_REG_DEVICE_ID, FXL6408_REG_DEVICE_ID },60 { FXL6408_REG_INPUT_STATUS, FXL6408_REG_INPUT_STATUS },61};62 63static const struct regmap_access_table rd_table = {64 .yes_ranges = rd_range,65 .n_yes_ranges = ARRAY_SIZE(rd_range),66};67 68static const struct regmap_access_table wr_table = {69 .yes_ranges = wr_range,70 .n_yes_ranges = ARRAY_SIZE(wr_range),71};72 73static const struct regmap_access_table volatile_table = {74 .yes_ranges = volatile_range,75 .n_yes_ranges = ARRAY_SIZE(volatile_range),76};77 78static const struct regmap_config regmap = {79 .reg_bits = 8,80 .val_bits = 8,81 82 .max_register = FXL6408_REG_INT_STS,83 .wr_table = &wr_table,84 .rd_table = &rd_table,85 .volatile_table = &volatile_table,86 87 .cache_type = REGCACHE_MAPLE,88 .num_reg_defaults_raw = FXL6408_REG_INT_STS + 1,89};90 91static int fxl6408_identify(struct device *dev, struct regmap *regmap)92{93 int val, ret;94 95 ret = regmap_read(regmap, FXL6408_REG_DEVICE_ID, &val);96 if (ret)97 return dev_err_probe(dev, ret, "error reading DEVICE_ID\n");98 if (val >> FXL6408_MF_SHIFT != FXL6408_MF_FAIRCHILD)99 return dev_err_probe(dev, -ENODEV, "invalid device id 0x%02x\n", val);100 101 return 0;102}103 104static int fxl6408_probe(struct i2c_client *client)105{106 struct device *dev = &client->dev;107 int ret;108 struct gpio_regmap_config gpio_config = {109 .parent = dev,110 .ngpio = FXL6408_NGPIO,111 .reg_dat_base = GPIO_REGMAP_ADDR(FXL6408_REG_INPUT_STATUS),112 .reg_set_base = GPIO_REGMAP_ADDR(FXL6408_REG_OUTPUT),113 .reg_dir_out_base = GPIO_REGMAP_ADDR(FXL6408_REG_IO_DIR),114 .ngpio_per_reg = FXL6408_NGPIO,115 };116 117 gpio_config.regmap = devm_regmap_init_i2c(client, ®map);118 if (IS_ERR(gpio_config.regmap))119 return dev_err_probe(dev, PTR_ERR(gpio_config.regmap),120 "failed to allocate register map\n");121 122 ret = fxl6408_identify(dev, gpio_config.regmap);123 if (ret)124 return ret;125 126 /* Disable High-Z of outputs, so that our OUTPUT updates actually take effect. */127 ret = regmap_write(gpio_config.regmap, FXL6408_REG_OUTPUT_HIGH_Z, 0);128 if (ret)129 return dev_err_probe(dev, ret, "failed to write 'output high Z' register\n");130 131 return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));132}133 134static const __maybe_unused struct of_device_id fxl6408_dt_ids[] = {135 { .compatible = "fcs,fxl6408" },136 { }137};138MODULE_DEVICE_TABLE(of, fxl6408_dt_ids);139 140static const struct i2c_device_id fxl6408_id[] = {141 { "fxl6408" },142 { }143};144MODULE_DEVICE_TABLE(i2c, fxl6408_id);145 146static struct i2c_driver fxl6408_driver = {147 .driver = {148 .name = "fxl6408",149 .of_match_table = fxl6408_dt_ids,150 },151 .probe = fxl6408_probe,152 .id_table = fxl6408_id,153};154module_i2c_driver(fxl6408_driver);155 156MODULE_AUTHOR("Emanuele Ghidoli <emanuele.ghidoli@toradex.com>");157MODULE_DESCRIPTION("FXL6408 GPIO driver");158MODULE_LICENSE("GPL");159