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_MAPLE, |
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(map: regmap, FXL6408_REG_DEVICE_ID, val: &val); |
96 | if (ret) |
97 | return dev_err_probe(dev, err: ret, fmt: "error reading DEVICE_ID\n" ); |
98 | if (val >> FXL6408_MF_SHIFT != FXL6408_MF_FAIRCHILD) |
99 | return dev_err_probe(dev, err: -ENODEV, fmt: "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(ptr: gpio_config.regmap)) |
119 | return dev_err_probe(dev, err: PTR_ERR(ptr: gpio_config.regmap), |
120 | fmt: "failed to allocate register map\n" ); |
121 | |
122 | ret = fxl6408_identify(dev, regmap: 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(map: gpio_config.regmap, FXL6408_REG_OUTPUT_HIGH_Z, val: 0); |
128 | if (ret) |
129 | return dev_err_probe(dev, err: ret, fmt: "failed to write 'output high Z' register\n" ); |
130 | |
131 | return PTR_ERR_OR_ZERO(ptr: devm_gpio_regmap_register(dev, config: &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 | |