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
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 = of_match_ptr(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 <peda@axentia.se>");
153MODULE_LICENSE("GPL v2");
154