/drivers/staging/iio/addac/adt7316-spi.c

  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 __devinit 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 int __devexit adt7316_spi_remove(struct spi_device *spi_dev)
120{
121	return adt7316_remove(&spi_dev->dev);
122}
123
124static const struct spi_device_id adt7316_spi_id[] = {
125	{ "adt7316", 0 },
126	{ "adt7317", 0 },
127	{ "adt7318", 0 },
128	{ "adt7516", 0 },
129	{ "adt7517", 0 },
130	{ "adt7519", 0 },
131	{ }
132};
133
134MODULE_DEVICE_TABLE(spi, adt7316_spi_id);
135
136#ifdef CONFIG_PM
137static int adt7316_spi_suspend(struct spi_device *spi_dev, pm_message_t message)
138{
139	return adt7316_disable(&spi_dev->dev);
140}
141
142static int adt7316_spi_resume(struct spi_device *spi_dev)
143{
144	return adt7316_enable(&spi_dev->dev);
145}
146#else
147# define adt7316_spi_suspend NULL
148# define adt7316_spi_resume  NULL
149#endif
150
151static struct spi_driver adt7316_driver = {
152	.driver = {
153		.name = "adt7316",
154		.bus = &spi_bus_type,
155		.owner = THIS_MODULE,
156	},
157	.probe = adt7316_spi_probe,
158	.remove = __devexit_p(adt7316_spi_remove),
159	.suspend = adt7316_spi_suspend,
160	.resume = adt7316_spi_resume,
161	.id_table = adt7316_spi_id,
162};
163
164static __init int adt7316_spi_init(void)
165{
166	return spi_register_driver(&adt7316_driver);
167}
168
169static __exit void adt7316_spi_exit(void)
170{
171	spi_unregister_driver(&adt7316_driver);
172}
173
174MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
175MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and"
176			"ADT7516/7/9 digital temperature sensor, ADC and DAC");
177MODULE_LICENSE("GPL v2");
178
179module_init(adt7316_spi_init);
180module_exit(adt7316_spi_exit);