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/module.h>
10 #include <linux/mux/driver.h>
11 #include <linux/of_platform.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 
20 enum adgs1408_chip_id {
21 	ADGS1408 = 1,
22 	ADGS1409,
23 };
24 
adgs1408_spi_reg_write(struct spi_device * spi,u8 reg_addr,u8 reg_data)25 static 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 
adgs1408_set(struct mux_control * mux,int state)36 static 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 
49 static const struct mux_control_ops adgs1408_ops = {
50 	.set = adgs1408_set,
51 };
52 
adgs1408_probe(struct spi_device * spi)53 static 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)of_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 		/* fall through */
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 
105 static const struct spi_device_id adgs1408_spi_id[] = {
106 	{ "adgs1408", ADGS1408 },
107 	{ "adgs1409", ADGS1409 },
108 	{ }
109 };
110 MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);
111 
112 static const struct of_device_id adgs1408_of_match[] = {
113 	{ .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
114 	{ .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
115 	{ }
116 };
117 MODULE_DEVICE_TABLE(of, adgs1408_of_match);
118 
119 static struct spi_driver adgs1408_driver = {
120 	.driver = {
121 		.name = "adgs1408",
122 		.of_match_table = of_match_ptr(adgs1408_of_match),
123 	},
124 	.probe = adgs1408_probe,
125 	.id_table = adgs1408_spi_id,
126 };
127 module_spi_driver(adgs1408_driver);
128 
129 MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
130 MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
131 MODULE_LICENSE("GPL");
132