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
  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
  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
  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
  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
  92 static 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
 119 static int __devexit adt7316_spi_remove(struct spi_device *spi_dev)
 120 {
 121         return adt7316_remove(&spi_dev->dev);
 122 }
 123
 124 static 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
 134 MODULE_DEVICE_TABLE(spi, adt7316_spi_id);
 135
 136 static struct spi_driver adt7316_driver = {
 137         .driver = {
 138                 .name = "adt7316",
 139                 .pm = ADT7316_PM_OPS,
 140                 .owner = THIS_MODULE,
 141         },
 142         .probe = adt7316_spi_probe,
 143         .remove = __devexit_p(adt7316_spi_remove),
 144         .id_table = adt7316_spi_id,
 145 };
 146 module_spi_driver(adt7316_driver);
 147
 148 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
 149 MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and"
 150                         "ADT7516/7/9 digital temperature sensor, ADC and DAC");
 151 MODULE_LICENSE("GPL v2");