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afda08c4 PR |
1 | /* |
2 | * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux | |
3 | * | |
4 | * Copyright (C) 2017 Axentia Technologies AB | |
5 | * | |
6 | * Author: Peter Rosin <peda@axentia.se> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/err.h> | |
14 | #include <linux/i2c.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/mux/driver.h> | |
17 | #include <linux/property.h> | |
18 | ||
19 | #define ADG792A_LDSW BIT(0) | |
20 | #define ADG792A_RESETB BIT(1) | |
21 | #define ADG792A_DISABLE(mux) (0x50 | (mux)) | |
22 | #define ADG792A_DISABLE_ALL (0x5f) | |
23 | #define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state)) | |
24 | #define ADG792A_MUX_ALL(state) (0xc0 | (state)) | |
25 | ||
26 | static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset) | |
27 | { | |
28 | u8 data = ADG792A_RESETB | ADG792A_LDSW; | |
29 | ||
30 | /* ADG792A_RESETB is active low, the chip resets when it is zero. */ | |
31 | if (reset) | |
32 | data &= ~ADG792A_RESETB; | |
33 | ||
34 | return i2c_smbus_write_byte_data(i2c, cmd, data); | |
35 | } | |
36 | ||
37 | static int adg792a_set(struct mux_control *mux, int state) | |
38 | { | |
39 | struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent); | |
40 | u8 cmd; | |
41 | ||
42 | if (mux->chip->controllers == 1) { | |
43 | /* parallel mux controller operation */ | |
44 | if (state == MUX_IDLE_DISCONNECT) | |
45 | cmd = ADG792A_DISABLE_ALL; | |
46 | else | |
47 | cmd = ADG792A_MUX_ALL(state); | |
48 | } else { | |
49 | unsigned int controller = mux_control_get_index(mux); | |
50 | ||
51 | if (state == MUX_IDLE_DISCONNECT) | |
52 | cmd = ADG792A_DISABLE(controller); | |
53 | else | |
54 | cmd = ADG792A_MUX(controller, state); | |
55 | } | |
56 | ||
57 | return adg792a_write_cmd(i2c, cmd, 0); | |
58 | } | |
59 | ||
60 | static const struct mux_control_ops adg792a_ops = { | |
61 | .set = adg792a_set, | |
62 | }; | |
63 | ||
64 | static int adg792a_probe(struct i2c_client *i2c, | |
65 | const struct i2c_device_id *id) | |
66 | { | |
67 | struct device *dev = &i2c->dev; | |
68 | struct mux_chip *mux_chip; | |
69 | s32 idle_state[3]; | |
70 | u32 cells; | |
71 | int ret; | |
72 | int i; | |
73 | ||
74 | if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
75 | return -ENODEV; | |
76 | ||
77 | ret = device_property_read_u32(dev, "#mux-control-cells", &cells); | |
78 | if (ret < 0) | |
79 | return ret; | |
80 | if (cells >= 2) | |
81 | return -EINVAL; | |
82 | ||
83 | mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0); | |
84 | if (IS_ERR(mux_chip)) | |
85 | return PTR_ERR(mux_chip); | |
86 | ||
87 | mux_chip->ops = &adg792a_ops; | |
88 | ||
89 | ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1); | |
90 | if (ret < 0) | |
91 | return ret; | |
92 | ||
93 | ret = device_property_read_u32_array(dev, "idle-state", | |
94 | (u32 *)idle_state, | |
95 | mux_chip->controllers); | |
96 | if (ret < 0) { | |
97 | idle_state[0] = MUX_IDLE_AS_IS; | |
98 | idle_state[1] = MUX_IDLE_AS_IS; | |
99 | idle_state[2] = MUX_IDLE_AS_IS; | |
100 | } | |
101 | ||
102 | for (i = 0; i < mux_chip->controllers; ++i) { | |
103 | struct mux_control *mux = &mux_chip->mux[i]; | |
104 | ||
105 | mux->states = 4; | |
106 | ||
107 | switch (idle_state[i]) { | |
108 | case MUX_IDLE_DISCONNECT: | |
109 | case MUX_IDLE_AS_IS: | |
110 | case 0 ... 4: | |
111 | mux->idle_state = idle_state[i]; | |
112 | break; | |
113 | default: | |
114 | dev_err(dev, "invalid idle-state %d\n", idle_state[i]); | |
115 | return -EINVAL; | |
116 | } | |
117 | } | |
118 | ||
119 | ret = devm_mux_chip_register(dev, mux_chip); | |
120 | if (ret < 0) | |
121 | return ret; | |
122 | ||
123 | if (cells) | |
124 | dev_info(dev, "3x single pole quadruple throw muxes registered\n"); | |
125 | else | |
126 | dev_info(dev, "triple pole quadruple throw mux registered\n"); | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | static const struct i2c_device_id adg792a_id[] = { | |
132 | { .name = "adg792a", }, | |
133 | { .name = "adg792g", }, | |
134 | { } | |
135 | }; | |
136 | MODULE_DEVICE_TABLE(i2c, adg792a_id); | |
137 | ||
138 | static const struct of_device_id adg792a_of_match[] = { | |
139 | { .compatible = "adi,adg792a", }, | |
140 | { .compatible = "adi,adg792g", }, | |
141 | { } | |
142 | }; | |
143 | MODULE_DEVICE_TABLE(of, adg792a_of_match); | |
144 | ||
145 | static struct i2c_driver adg792a_driver = { | |
146 | .driver = { | |
147 | .name = "adg792a", | |
148 | .of_match_table = of_match_ptr(adg792a_of_match), | |
149 | }, | |
150 | .probe = adg792a_probe, | |
151 | .id_table = adg792a_id, | |
152 | }; | |
153 | module_i2c_driver(adg792a_driver); | |
154 | ||
155 | MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver"); | |
156 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); | |
157 | MODULE_LICENSE("GPL v2"); |