drivers/iio/humidity/hts221_i2c.c

   1 /*
   2  * STMicroelectronics hts221 i2c driver
   3  *
   4  * Copyright 2016 STMicroelectronics Inc.
   5  *
   6  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
   7  *
   8  * Licensed under the GPL-2.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include <linux/slab.h>
  15 #include "hts221.h"
  16
  17 #define I2C_AUTO_INCREMENT      0x80
  18
  19 static int hts221_i2c_read(struct device *dev, u8 addr, int len, u8 *data)
  20 {
  21         struct i2c_msg msg[2];
  22         struct i2c_client *client = to_i2c_client(dev);
  23
  24         if (len > 1)
  25                 addr |= I2C_AUTO_INCREMENT;
  26
  27         msg[0].addr = client->addr;
  28         msg[0].flags = client->flags;
  29         msg[0].len = 1;
  30         msg[0].buf = &addr;
  31
  32         msg[1].addr = client->addr;
  33         msg[1].flags = client->flags | I2C_M_RD;
  34         msg[1].len = len;
  35         msg[1].buf = data;
  36
  37         return i2c_transfer(client->adapter, msg, 2);
  38 }
  39
  40 static int hts221_i2c_write(struct device *dev, u8 addr, int len, u8 *data)
  41 {
  42         u8 send[len + 1];
  43         struct i2c_msg msg;
  44         struct i2c_client *client = to_i2c_client(dev);
  45
  46         if (len > 1)
  47                 addr |= I2C_AUTO_INCREMENT;
  48
  49         send[0] = addr;
  50         memcpy(&send[1], data, len * sizeof(u8));
  51
  52         msg.addr = client->addr;
  53         msg.flags = client->flags;
  54         msg.len = len + 1;
  55         msg.buf = send;
  56
  57         return i2c_transfer(client->adapter, &msg, 1);
  58 }
  59
  60 static const struct hts221_transfer_function hts221_transfer_fn = {
  61         .read = hts221_i2c_read,
  62         .write = hts221_i2c_write,
  63 };
  64
  65 static int hts221_i2c_probe(struct i2c_client *client,
  66                             const struct i2c_device_id *id)
  67 {
  68         struct hts221_hw *hw;
  69         struct iio_dev *iio_dev;
  70
  71         iio_dev = devm_iio_device_alloc(&client->dev, sizeof(*hw));
  72         if (!iio_dev)
  73                 return -ENOMEM;
  74
  75         i2c_set_clientdata(client, iio_dev);
  76
  77         hw = iio_priv(iio_dev);
  78         hw->name = client->name;
  79         hw->dev = &client->dev;
  80         hw->irq = client->irq;
  81         hw->tf = &hts221_transfer_fn;
  82
  83         return hts221_probe(iio_dev);
  84 }
  85
  86 static const struct of_device_id hts221_i2c_of_match[] = {
  87         { .compatible = "st,hts221", },
  88         {},
  89 };
  90 MODULE_DEVICE_TABLE(of, hts221_i2c_of_match);
  91
  92 static const struct i2c_device_id hts221_i2c_id_table[] = {
  93         { HTS221_DEV_NAME },
  94         {},
  95 };
  96 MODULE_DEVICE_TABLE(i2c, hts221_i2c_id_table);
  97
  98 static struct i2c_driver hts221_driver = {
  99         .driver = {
 100                 .name = "hts221_i2c",
 101                 .of_match_table = of_match_ptr(hts221_i2c_of_match),
 102         },
 103         .probe = hts221_i2c_probe,
 104         .id_table = hts221_i2c_id_table,
 105 };
 106 module_i2c_driver(hts221_driver);
 107
 108 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 109 MODULE_DESCRIPTION("STMicroelectronics hts221 i2c driver");
 110 MODULE_LICENSE("GPL v2");