adt7316-spi.c

  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
 25static 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
 54static 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
 77static int adt7316_spi_read(void *client, u8 reg, u8 *data)
 78{
 79	return adt7316_spi_multi_read(client, reg, 1, data);
 80}
 81
 82static 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
 91static 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
117static 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
127MODULE_DEVICE_TABLE(spi, adt7316_spi_id);
128
129static 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
139MODULE_DEVICE_TABLE(of, adt7316_of_spi_match);
140
141static 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};
150module_spi_driver(adt7316_driver);
151
152MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
153MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and ADT7516/7/9 digital temperature sensor, ADC and DAC");
154MODULE_LICENSE("GPL v2");