kernel/drivers/iio/common/st_sensors/st_sensors_i2c.c

   1 /*
   2  * STMicroelectronics sensors i2c library driver
   3  *
   4  * Copyright 2012-2013 STMicroelectronics Inc.
   5  *
   6  * Denis Ciocca <denis.ciocca@st.com>
   7  *
   8  * Licensed under the GPL-2.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/of_device.h>
  16
  17 #include <linux/iio/common/st_sensors_i2c.h>
  18
  19
  20 #define ST_SENSORS_I2C_MULTIREAD        0x80
  21
  22 static unsigned int st_sensors_i2c_get_irq(struct iio_dev *indio_dev)
  23 {
  24         struct st_sensor_data *sdata = iio_priv(indio_dev);
  25
  26         return to_i2c_client(sdata->dev)->irq;
  27 }
  28
  29 static int st_sensors_i2c_read_byte(struct st_sensor_transfer_buffer *tb,
  30                                 struct device *dev, u8 reg_addr, u8 *res_byte)
  31 {
  32         int err;
  33
  34         err = i2c_smbus_read_byte_data(to_i2c_client(dev), reg_addr);
  35         if (err < 0)
  36                 goto st_accel_i2c_read_byte_error;
  37
  38         *res_byte = err & 0xff;
  39
  40 st_accel_i2c_read_byte_error:
  41         return err < 0 ? err : 0;
  42 }
  43
  44 static int st_sensors_i2c_read_multiple_byte(
  45                 struct st_sensor_transfer_buffer *tb, struct device *dev,
  46                         u8 reg_addr, int len, u8 *data, bool multiread_bit)
  47 {
  48         if (multiread_bit)
  49                 reg_addr |= ST_SENSORS_I2C_MULTIREAD;
  50
  51         return i2c_smbus_read_i2c_block_data(to_i2c_client(dev),
  52                                                         reg_addr, len, data);
  53 }
  54
  55 static int st_sensors_i2c_write_byte(struct st_sensor_transfer_buffer *tb,
  56                                 struct device *dev, u8 reg_addr, u8 data)
  57 {
  58         return i2c_smbus_write_byte_data(to_i2c_client(dev), reg_addr, data);
  59 }
  60
  61 static const struct st_sensor_transfer_function st_sensors_tf_i2c = {
  62         .read_byte = st_sensors_i2c_read_byte,
  63         .write_byte = st_sensors_i2c_write_byte,
  64         .read_multiple_byte = st_sensors_i2c_read_multiple_byte,
  65 };
  66
  67 void st_sensors_i2c_configure(struct iio_dev *indio_dev,
  68                 struct i2c_client *client, struct st_sensor_data *sdata)
  69 {
  70         i2c_set_clientdata(client, indio_dev);
  71
  72         indio_dev->dev.parent = &client->dev;
  73         indio_dev->name = client->name;
  74
  75         sdata->dev = &client->dev;
  76         sdata->tf = &st_sensors_tf_i2c;
  77         sdata->get_irq_data_ready = st_sensors_i2c_get_irq;
  78 }
  79 EXPORT_SYMBOL(st_sensors_i2c_configure);
  80
  81 #ifdef CONFIG_OF
  82 /**
  83  * st_sensors_of_i2c_probe() - device tree probe for ST I2C sensors
  84  * @client: the I2C client device for the sensor
  85  * @match: the OF match table for the device, containing compatible strings
  86  *      but also a .data field with the corresponding internal kernel name
  87  *      used by this sensor.
  88  *
  89  * In effect this function matches a compatible string to an internal kernel
  90  * name for a certain sensor device, so that the rest of the autodetection can
  91  * rely on that name from this point on. I2C client devices will be renamed
  92  * to match the internal kernel convention.
  93  */
  94 void st_sensors_of_i2c_probe(struct i2c_client *client,
  95                              const struct of_device_id *match)
  96 {
  97         const struct of_device_id *of_id;
  98
  99         of_id = of_match_device(match, &client->dev);
 100         if (!of_id)
 101                 return;
 102
 103         /* The name from the OF match takes precedence if present */
 104         strncpy(client->name, of_id->data, sizeof(client->name));
 105         client->name[sizeof(client->name) - 1] = '\0';
 106 }
 107 EXPORT_SYMBOL(st_sensors_of_i2c_probe);
 108 #endif
 109
 110 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 111 MODULE_DESCRIPTION("STMicroelectronics ST-sensors i2c driver");
 112 MODULE_LICENSE("GPL v2");