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