1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * API bus driver for ADT7316/7/8 ADT7516/7/9 digital temperature
4  * sensor, ADC and DAC
5  *
6  * Copyright 2010 Analog Devices Inc.
7  */
8 
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <linux/spi/spi.h>
14 
15 #include "adt7316.h"
16 
17 #define ADT7316_SPI_MAX_FREQ_HZ		5000000
18 #define ADT7316_SPI_CMD_READ		0x91
19 #define ADT7316_SPI_CMD_WRITE		0x90
20 
21 /*
22  * adt7316 register access by SPI
23  */
24 
adt7316_spi_multi_read(void * client,u8 reg,u8 count,u8 * data)25 static int adt7316_spi_multi_read(void *client, u8 reg, u8 count, u8 *data)
26 {
27 	struct spi_device *spi_dev = client;
28 	u8 cmd[2];
29 	int ret;
30 
31 	if (count > ADT7316_REG_MAX_ADDR)
32 		count = ADT7316_REG_MAX_ADDR;
33 
34 	cmd[0] = ADT7316_SPI_CMD_WRITE;
35 	cmd[1] = reg;
36 
37 	ret = spi_write(spi_dev, cmd, 2);
38 	if (ret < 0) {
39 		dev_err(&spi_dev->dev, "SPI fail to select reg\n");
40 		return ret;
41 	}
42 
43 	cmd[0] = ADT7316_SPI_CMD_READ;
44 
45 	ret = spi_write_then_read(spi_dev, cmd, 1, data, count);
46 	if (ret < 0) {
47 		dev_err(&spi_dev->dev, "SPI read data error\n");
48 		return ret;
49 	}
50 
51 	return 0;
52 }
53 
adt7316_spi_multi_write(void * client,u8 reg,u8 count,u8 * data)54 static int adt7316_spi_multi_write(void *client, u8 reg, u8 count, u8 *data)
55 {
56 	struct spi_device *spi_dev = client;
57 	u8 buf[ADT7316_REG_MAX_ADDR + 2];
58 	int i, ret;
59 
60 	if (count > ADT7316_REG_MAX_ADDR)
61 		count = ADT7316_REG_MAX_ADDR;
62 
63 	buf[0] = ADT7316_SPI_CMD_WRITE;
64 	buf[1] = reg;
65 	for (i = 0; i < count; i++)
66 		buf[i + 2] = data[i];
67 
68 	ret = spi_write(spi_dev, buf, count + 2);
69 	if (ret < 0) {
70 		dev_err(&spi_dev->dev, "SPI write error\n");
71 		return ret;
72 	}
73 
74 	return ret;
75 }
76 
adt7316_spi_read(void * client,u8 reg,u8 * data)77 static int adt7316_spi_read(void *client, u8 reg, u8 *data)
78 {
79 	return adt7316_spi_multi_read(client, reg, 1, data);
80 }
81 
adt7316_spi_write(void * client,u8 reg,u8 val)82 static int adt7316_spi_write(void *client, u8 reg, u8 val)
83 {
84 	return adt7316_spi_multi_write(client, reg, 1, &val);
85 }
86 
87 /*
88  * device probe and remove
89  */
90 
adt7316_spi_probe(struct spi_device * spi_dev)91 static int adt7316_spi_probe(struct spi_device *spi_dev)
92 {
93 	struct adt7316_bus bus = {
94 		.client = spi_dev,
95 		.irq = spi_dev->irq,
96 		.read = adt7316_spi_read,
97 		.write = adt7316_spi_write,
98 		.multi_read = adt7316_spi_multi_read,
99 		.multi_write = adt7316_spi_multi_write,
100 	};
101 
102 	/* don't exceed max specified SPI CLK frequency */
103 	if (spi_dev->max_speed_hz > ADT7316_SPI_MAX_FREQ_HZ) {
104 		dev_err(&spi_dev->dev, "SPI CLK %d Hz?\n",
105 			spi_dev->max_speed_hz);
106 		return -EINVAL;
107 	}
108 
109 	/* switch from default I2C protocol to SPI protocol */
110 	adt7316_spi_write(spi_dev, 0, 0);
111 	adt7316_spi_write(spi_dev, 0, 0);
112 	adt7316_spi_write(spi_dev, 0, 0);
113 
114 	return adt7316_probe(&spi_dev->dev, &bus, spi_dev->modalias);
115 }
116 
117 static const struct spi_device_id adt7316_spi_id[] = {
118 	{ "adt7316", 0 },
119 	{ "adt7317", 0 },
120 	{ "adt7318", 0 },
121 	{ "adt7516", 0 },
122 	{ "adt7517", 0 },
123 	{ "adt7519", 0 },
124 	{ }
125 };
126 
127 MODULE_DEVICE_TABLE(spi, adt7316_spi_id);
128 
129 static const struct of_device_id adt7316_of_spi_match[] = {
130 	{ .compatible = "adi,adt7316" },
131 	{ .compatible = "adi,adt7317" },
132 	{ .compatible = "adi,adt7318" },
133 	{ .compatible = "adi,adt7516" },
134 	{ .compatible = "adi,adt7517" },
135 	{ .compatible = "adi,adt7519" },
136 	{ }
137 };
138 
139 MODULE_DEVICE_TABLE(of, adt7316_of_spi_match);
140 
141 static struct spi_driver adt7316_driver = {
142 	.driver = {
143 		.name = "adt7316",
144 		.of_match_table = adt7316_of_spi_match,
145 		.pm = ADT7316_PM_OPS,
146 	},
147 	.probe = adt7316_spi_probe,
148 	.id_table = adt7316_spi_id,
149 };
150 module_spi_driver(adt7316_driver);
151 
152 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
153 MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and ADT7516/7/9 digital temperature sensor, ADC and DAC");
154 MODULE_LICENSE("GPL v2");
155