1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * FXL6408 GPIO driver 4 * 5 * Copyright 2023 Toradex 6 * 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 0x01 18 #define FXL6408_MF_FAIRCHILD 0b101 19 #define FXL6408_MF_SHIFT 5 20 21 /* Bits set here indicate that the GPIO is an output. */ 22 #define FXL6408_REG_IO_DIR 0x03 23 24 /* 25 * Bits set here, when the corresponding bit of IO_DIR is set, drive 26 * the output high instead of low. 27 */ 28 #define FXL6408_REG_OUTPUT 0x05 29 30 /* Bits here make the output High-Z, instead of the OUTPUT value. */ 31 #define FXL6408_REG_OUTPUT_HIGH_Z 0x07 32 33 /* Returns the current status (1 = HIGH) of the input pins. */ 34 #define FXL6408_REG_INPUT_STATUS 0x0f 35 36 /* 37 * Return the current interrupt status 38 * 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 0x13 43 44 #define FXL6408_NGPIO 8 45 46 static 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 52 static 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 58 static 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 63 static const struct regmap_access_table rd_table = { 64 .yes_ranges = rd_range, 65 .n_yes_ranges = ARRAY_SIZE(rd_range), 66 }; 67 68 static const struct regmap_access_table wr_table = { 69 .yes_ranges = wr_range, 70 .n_yes_ranges = ARRAY_SIZE(wr_range), 71 }; 72 73 static const struct regmap_access_table volatile_table = { 74 .yes_ranges = volatile_range, 75 .n_yes_ranges = ARRAY_SIZE(volatile_range), 76 }; 77 78 static 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_RBTREE, 88 .num_reg_defaults_raw = FXL6408_REG_INT_STS + 1, 89 }; 90 91 static 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 } 103 104 static 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 } 133 134 static const __maybe_unused struct of_device_id fxl6408_dt_ids[] = { 135 { .compatible = "fcs,fxl6408" }, 136 { } 137 }; 138 MODULE_DEVICE_TABLE(of, fxl6408_dt_ids); 139 140 static const struct i2c_device_id fxl6408_id[] = { 141 { "fxl6408", 0 }, 142 { } 143 }; 144 MODULE_DEVICE_TABLE(i2c, fxl6408_id); 145 146 static 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 }; 154 module_i2c_driver(fxl6408_driver); 155 156 MODULE_AUTHOR("Emanuele Ghidoli <emanuele.ghidoli@toradex.com>"); 157 MODULE_DESCRIPTION("FXL6408 GPIO driver"); 158 MODULE_LICENSE("GPL"); 159