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 <peda@axentia.se>
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 
adg792a_write_cmd(struct i2c_client * i2c,u8 cmd,int reset)23 static 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 
adg792a_set(struct mux_control * mux,int state)34 static 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 
57 static const struct mux_control_ops adg792a_ops = {
58 	.set = adg792a_set,
59 };
60 
adg792a_probe(struct i2c_client * i2c)61 static 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 
127 static const struct i2c_device_id adg792a_id[] = {
128 	{ .name = "adg792a", },
129 	{ .name = "adg792g", },
130 	{ }
131 };
132 MODULE_DEVICE_TABLE(i2c, adg792a_id);
133 
134 static const struct of_device_id adg792a_of_match[] = {
135 	{ .compatible = "adi,adg792a", },
136 	{ .compatible = "adi,adg792g", },
137 	{ }
138 };
139 MODULE_DEVICE_TABLE(of, adg792a_of_match);
140 
141 static struct i2c_driver adg792a_driver = {
142 	.driver		= {
143 		.name		= "adg792a",
144 		.of_match_table = of_match_ptr(adg792a_of_match),
145 	},
146 	.probe_new	= adg792a_probe,
147 	.id_table	= adg792a_id,
148 };
149 module_i2c_driver(adg792a_driver);
150 
151 MODULE_DESCRIPTION("Analog Devices ADG792A/G Triple 4:1 mux driver");
152 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
153 MODULE_LICENSE("GPL v2");
154