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 
20 enum adgs1408_chip_id {
21 	ADGS1408 = 1,
22 	ADGS1409,
23 };
24 
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 
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 
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 = (kernel_ulong_t)spi_get_device_match_data(spi);
63 
64 	mux_chip = devm_mux_chip_alloc(dev, 1, 0);
65 	if (IS_ERR(mux_chip))
66 		return PTR_ERR(mux_chip);
67 
68 	mux_chip->ops = &adgs1408_ops;
69 
70 	ret = adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, ADGS1408_DISABLE);
71 	if (ret < 0)
72 		return ret;
73 
74 	ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
75 	if (ret < 0)
76 		idle_state = MUX_IDLE_AS_IS;
77 
78 	mux = mux_chip->mux;
79 
80 	if (chip_id == ADGS1408)
81 		mux->states = 8;
82 	else
83 		mux->states = 4;
84 
85 	switch (idle_state) {
86 	case MUX_IDLE_DISCONNECT:
87 	case MUX_IDLE_AS_IS:
88 	case 0 ... 7:
89 		/* adgs1409 supports only 4 states */
90 		if (idle_state < mux->states) {
91 			mux->idle_state = idle_state;
92 			break;
93 		}
94 		fallthrough;
95 	default:
96 		dev_err(dev, "invalid idle-state %d\n", idle_state);
97 		return -EINVAL;
98 	}
99 
100 	return devm_mux_chip_register(dev, mux_chip);
101 }
102 
103 static const struct spi_device_id adgs1408_spi_id[] = {
104 	{ "adgs1408", ADGS1408 },
105 	{ "adgs1409", ADGS1409 },
106 	{ }
107 };
108 MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);
109 
110 static const struct of_device_id adgs1408_of_match[] = {
111 	{ .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
112 	{ .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
113 	{ }
114 };
115 MODULE_DEVICE_TABLE(of, adgs1408_of_match);
116 
117 static struct spi_driver adgs1408_driver = {
118 	.driver = {
119 		.name = "adgs1408",
120 		.of_match_table = adgs1408_of_match,
121 	},
122 	.probe = adgs1408_probe,
123 	.id_table = adgs1408_spi_id,
124 };
125 module_spi_driver(adgs1408_driver);
126 
127 MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
128 MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
129 MODULE_LICENSE("GPL");
130