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
26static 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
55static 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
78static int adt7316_spi_read(void *client, u8 reg, u8 *data)
79{
80	return adt7316_spi_multi_read(client, reg, 1, data);
81}
82
83static 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
92static 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
119static 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
129MODULE_DEVICE_TABLE(spi, adt7316_spi_id);
130
131static struct spi_driver adt7316_driver = {
132	.driver = {
133		.name = "adt7316",
134		.pm = ADT7316_PM_OPS,
135		.owner = THIS_MODULE,
136	},
137	.probe = adt7316_spi_probe,
138	.id_table = adt7316_spi_id,
139};
140module_spi_driver(adt7316_driver);
141
142MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
143MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and ADT7516/7/9 digital temperature sensor, ADC and DAC");
144MODULE_LICENSE("GPL v2");
145