1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ADGS1408/ADGS1409 SPI MUX driver
4 *
5 * Copyright 2018 Analog Devices Inc.
6 */
7
8#include <linux/err.h>
9#include <linux/mod_devicetable.h>
10#include <linux/module.h>
11#include <linux/mux/driver.h>
12#include <linux/property.h>
13#include <linux/spi/spi.h>
14
15#define ADGS1408_SW_DATA       (0x01)
16#define ADGS1408_REG_READ(reg) ((reg) | 0x80)
17#define ADGS1408_DISABLE       (0x00)
18#define ADGS1408_MUX(state)    (((state) << 1) | 1)
19
20enum adgs1408_chip_id {
21	ADGS1408 = 1,
22	ADGS1409,
23};
24
25static int adgs1408_spi_reg_write(struct spi_device *spi,
26				  u8 reg_addr, u8 reg_data)
27{
28	u8 tx_buf[2];
29
30	tx_buf[0] = reg_addr;
31	tx_buf[1] = reg_data;
32
33	return spi_write_then_read(spi, tx_buf, sizeof(tx_buf), NULL, 0);
34}
35
36static int adgs1408_set(struct mux_control *mux, int state)
37{
38	struct spi_device *spi = to_spi_device(mux->chip->dev.parent);
39	u8 reg;
40
41	if (state == MUX_IDLE_DISCONNECT)
42		reg = ADGS1408_DISABLE;
43	else
44		reg = ADGS1408_MUX(state);
45
46	return adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, reg);
47}
48
49static const struct mux_control_ops adgs1408_ops = {
50	.set = adgs1408_set,
51};
52
53static int adgs1408_probe(struct spi_device *spi)
54{
55	struct device *dev = &spi->dev;
56	enum adgs1408_chip_id chip_id;
57	struct mux_chip *mux_chip;
58	struct mux_control *mux;
59	s32 idle_state;
60	int ret;
61
62	chip_id = (enum adgs1408_chip_id)device_get_match_data(dev);
63	if (!chip_id)
64		chip_id = spi_get_device_id(spi)->driver_data;
65
66	mux_chip = devm_mux_chip_alloc(dev, 1, 0);
67	if (IS_ERR(mux_chip))
68		return PTR_ERR(mux_chip);
69
70	mux_chip->ops = &adgs1408_ops;
71
72	ret = adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, ADGS1408_DISABLE);
73	if (ret < 0)
74		return ret;
75
76	ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
77	if (ret < 0)
78		idle_state = MUX_IDLE_AS_IS;
79
80	mux = mux_chip->mux;
81
82	if (chip_id == ADGS1408)
83		mux->states = 8;
84	else
85		mux->states = 4;
86
87	switch (idle_state) {
88	case MUX_IDLE_DISCONNECT:
89	case MUX_IDLE_AS_IS:
90	case 0 ... 7:
91		/* adgs1409 supports only 4 states */
92		if (idle_state < mux->states) {
93			mux->idle_state = idle_state;
94			break;
95		}
96		fallthrough;
97	default:
98		dev_err(dev, "invalid idle-state %d\n", idle_state);
99		return -EINVAL;
100	}
101
102	return devm_mux_chip_register(dev, mux_chip);
103}
104
105static const struct spi_device_id adgs1408_spi_id[] = {
106	{ "adgs1408", ADGS1408 },
107	{ "adgs1409", ADGS1409 },
108	{ }
109};
110MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);
111
112static const struct of_device_id adgs1408_of_match[] = {
113	{ .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
114	{ .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
115	{ }
116};
117MODULE_DEVICE_TABLE(of, adgs1408_of_match);
118
119static struct spi_driver adgs1408_driver = {
120	.driver = {
121		.name = "adgs1408",
122		.of_match_table = adgs1408_of_match,
123	},
124	.probe = adgs1408_probe,
125	.id_table = adgs1408_spi_id,
126};
127module_spi_driver(adgs1408_driver);
128
129MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
130MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
131MODULE_LICENSE("GPL");
132