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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Multiplexer driver for Analog Devices ADG792A/G Triple 4:1 mux
4 *
5 * Copyright (C) 2017 Axentia Technologies AB
6 *
7 * Author: Peter Rosin <[email protected]>
8 */
9
10#include <linux/err.h>
11#include <linux/i2c.h>
12#include <linux/module.h>
13#include <linux/mux/driver.h>
14#include <linux/property.h>
15
16#define ADG792A_LDSW BIT(0)
17#define ADG792A_RESETB BIT(1)
18#define ADG792A_DISABLE(mux) (0x50 | (mux))
19#define ADG792A_DISABLE_ALL (0x5f)
20#define ADG792A_MUX(mux, state) (0xc0 | (((mux) + 1) << 2) | (state))
21#define ADG792A_MUX_ALL(state) (0xc0 | (state))
22
23static int adg792a_write_cmd(struct i2c_client *i2c, u8 cmd, int reset)
24{
25 u8 data = ADG792A_RESETB | ADG792A_LDSW;
26
27 /* ADG792A_RESETB is active low, the chip resets when it is zero. */
28 if (reset)
29 data &= ~ADG792A_RESETB;
30
31 return i2c_smbus_write_byte_data(i2c, cmd, data);
32}
33
34static int adg792a_set(struct mux_control *mux, int state)
35{
36 struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
37 u8 cmd;
38
39 if (mux->chip->controllers == 1) {
40 /* parallel mux controller operation */
41 if (state == MUX_IDLE_DISCONNECT)
42 cmd = ADG792A_DISABLE_ALL;
43 else
44 cmd = ADG792A_MUX_ALL(state);
45 } else {
46 unsigned int controller = mux_control_get_index(mux);
47
48 if (state == MUX_IDLE_DISCONNECT)
49 cmd = ADG792A_DISABLE(controller);
50 else
51 cmd = ADG792A_MUX(controller, state);
52 }
53
54 return adg792a_write_cmd(i2c, cmd, 0);
55}
56
57static const struct mux_control_ops adg792a_ops = {
58 .set = adg792a_set,
59};
60
61static int adg792a_probe(struct i2c_client *i2c)
62{
63 struct device *dev = &i2c->dev;
64 struct mux_chip *mux_chip;
65 s32 idle_state[3];
66 u32 cells;
67 int ret;
68 int i;
69
70 if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
71 return -ENODEV;
72
73 ret = device_property_read_u32(dev, "#mux-control-cells", &cells);
74 if (ret < 0)
75 return ret;
76 if (cells >= 2)
77 return -EINVAL;
78
79 mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0);
80 if (IS_ERR(mux_chip))
81 return PTR_ERR(mux_chip);
82
83 mux_chip->ops = &adg792a_ops;
84
85 ret = adg792a_write_cmd(i2c, ADG792A_DISABLE_ALL, 1);
86 if (ret < 0)
87 return ret;
88
89 ret = device_property_read_u32_array(dev, "idle-state",
90 (u32 *)idle_state,
91 mux_chip->controllers);
92 if (ret < 0) {
93 idle_state[0] = MUX_IDLE_AS_IS;
94 idle_state[1] = MUX_IDLE_AS_IS;
95 idle_state[2] = MUX_IDLE_AS_IS;
96 }
97
98 for (i = 0; i < mux_chip->controllers; ++i) {
99 struct mux_control *mux = &mux_chip->mux[i];
100
101 mux->states = 4;
102
103 switch (idle_state[i]) {
104 case MUX_IDLE_DISCONNECT:
105 case MUX_IDLE_AS_IS:
106 case 0 ... 4:
107 mux->idle_state = idle_state[i];
108 break;
109 default:
110 dev_err(dev, "invalid idle-state %d\n", idle_state[i]);
111 return -EINVAL;
112 }
113 }
114
115 ret = devm_mux_chip_register(dev, mux_chip);
116 if (ret < 0)
117 return ret;
118
119 if (cells)
120 dev_info(dev, "3x single pole quadruple throw muxes registered\n");
121 else
122 dev_info(dev, "triple pole quadruple throw mux registered\n");
123
124 return 0;
125}
126
127static const struct i2c_device_id adg792a_id[] = {
128 { .name = "adg792a", },
129 { .name = "adg792g", },
130 { }
131};
132MODULE_DEVICE_TABLE(i2c, adg792a_id);
133
134static const struct of_device_id adg792a_of_match[] = {
135 { .compatible = "adi,adg792a", },
136 { .compatible = "adi,adg792g", },
137 { }
138};
139MODULE_DEVICE_TABLE(of, adg792a_of_match);
140
141static struct i2c_driver adg792a_driver = {
142 .driver = {
143 .name = "adg792a",
144 .of_match_table = adg792a_of_match,
145 },
146 .probe = adg792a_probe,
147 .id_table = adg792a_id,
148};
149module_i2c_driver(adg792a_driver);
150
151MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
152MODULE_AUTHOR("Peter Rosin <[email protected]>");
153MODULE_LICENSE("GPL v2");