LXR linux/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 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        },
 136        .probe = adt7316_spi_probe,
 137        .id_table = adt7316_spi_id,
 138};
 139module_spi_driver(adt7316_driver);
 140
 141MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
 142MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and ADT7516/7/9 digital temperature sensor, ADC and DAC");
 143MODULE_LICENSE("GPL v2");
 144