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/acpi.h>
  14 #include <linux/i2c.h>
  15 #include <linux/slab.h>
  16 #include "hts221.h"
  17
  18 #define I2C_AUTO_INCREMENT      0x80
  19
  20 static int hts221_i2c_read(struct device *dev, u8 addr, int len, u8 *data)
  21 {
  22         struct i2c_msg msg[2];
  23         struct i2c_client *client = to_i2c_client(dev);
  24
  25         if (len > 1)
  26                 addr |= I2C_AUTO_INCREMENT;
  27
  28         msg[0].addr = client->addr;
  29         msg[0].flags = client->flags;
  30         msg[0].len = 1;
  31         msg[0].buf = &addr;
  32
  33         msg[1].addr = client->addr;
  34         msg[1].flags = client->flags | I2C_M_RD;
  35         msg[1].len = len;
  36         msg[1].buf = data;
  37
  38         return i2c_transfer(client->adapter, msg, 2);
  39 }
  40
  41 static int hts221_i2c_write(struct device *dev, u8 addr, int len, u8 *data)
  42 {
  43         u8 send[len + 1];
  44         struct i2c_msg msg;
  45         struct i2c_client *client = to_i2c_client(dev);
  46
  47         if (len > 1)
  48                 addr |= I2C_AUTO_INCREMENT;
  49
  50         send[0] = addr;
  51         memcpy(&send[1], data, len * sizeof(u8));
  52
  53         msg.addr = client->addr;
  54         msg.flags = client->flags;
  55         msg.len = len + 1;
  56         msg.buf = send;
  57
  58         return i2c_transfer(client->adapter, &msg, 1);
  59 }
  60
  61 static const struct hts221_transfer_function hts221_transfer_fn = {
  62         .read = hts221_i2c_read,
  63         .write = hts221_i2c_write,
  64 };
  65
  66 static int hts221_i2c_probe(struct i2c_client *client,
  67                             const struct i2c_device_id *id)
  68 {
  69         return hts221_probe(&client->dev, client->irq,
  70                             client->name, &hts221_transfer_fn);
  71 }
  72
  73 static const struct acpi_device_id hts221_acpi_match[] = {
  74         {"SMO9100", 0},
  75         { },
  76 };
  77 MODULE_DEVICE_TABLE(acpi, hts221_acpi_match);
  78
  79 static const struct of_device_id hts221_i2c_of_match[] = {
  80         { .compatible = "st,hts221", },
  81         {},
  82 };
  83 MODULE_DEVICE_TABLE(of, hts221_i2c_of_match);
  84
  85 static const struct i2c_device_id hts221_i2c_id_table[] = {
  86         { HTS221_DEV_NAME },
  87         {},
  88 };
  89 MODULE_DEVICE_TABLE(i2c, hts221_i2c_id_table);
  90
  91 static struct i2c_driver hts221_driver = {
  92         .driver = {
  93                 .name = "hts221_i2c",
  94                 .pm = &hts221_pm_ops,
  95                 .of_match_table = of_match_ptr(hts221_i2c_of_match),
  96                 .acpi_match_table = ACPI_PTR(hts221_acpi_match),
  97         },
  98         .probe = hts221_i2c_probe,
  99         .id_table = hts221_i2c_id_table,
 100 };
 101 module_i2c_driver(hts221_driver);
 102
 103 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 104 MODULE_DESCRIPTION("STMicroelectronics hts221 i2c driver");
 105 MODULE_LICENSE("GPL v2");