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