LXR linux/drivers/iio/common/st_sensors/st_sensors

   1/*
   2 * STMicroelectronics sensors spi 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
  16#include <linux/iio/common/st_sensors_spi.h>
  17
  18
  19#define ST_SENSORS_SPI_MULTIREAD        0xc0
  20#define ST_SENSORS_SPI_READ             0x80
  21
  22static unsigned int st_sensors_spi_get_irq(struct iio_dev *indio_dev)
  23{
  24        struct st_sensor_data *sdata = iio_priv(indio_dev);
  25
  26        return to_spi_device(sdata->dev)->irq;
  27}
  28
  29static int st_sensors_spi_read(struct st_sensor_transfer_buffer *tb,
  30        struct device *dev, u8 reg_addr, int len, u8 *data, bool multiread_bit)
  31{
  32        int err;
  33
  34        struct spi_transfer xfers[] = {
  35                {
  36                        .tx_buf = tb->tx_buf,
  37                        .bits_per_word = 8,
  38                        .len = 1,
  39                },
  40                {
  41                        .rx_buf = tb->rx_buf,
  42                        .bits_per_word = 8,
  43                        .len = len,
  44                }
  45        };
  46
  47        mutex_lock(&tb->buf_lock);
  48        if ((multiread_bit) && (len > 1))
  49                tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_MULTIREAD;
  50        else
  51                tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_READ;
  52
  53        err = spi_sync_transfer(to_spi_device(dev), xfers, ARRAY_SIZE(xfers));
  54        if (err)
  55                goto acc_spi_read_error;
  56
  57        memcpy(data, tb->rx_buf, len);
  58        mutex_unlock(&tb->buf_lock);
  59        return len;
  60
  61acc_spi_read_error:
  62        mutex_unlock(&tb->buf_lock);
  63        return err;
  64}
  65
  66static int st_sensors_spi_read_byte(struct st_sensor_transfer_buffer *tb,
  67                                struct device *dev, u8 reg_addr, u8 *res_byte)
  68{
  69        return st_sensors_spi_read(tb, dev, reg_addr, 1, res_byte, false);
  70}
  71
  72static int st_sensors_spi_read_multiple_byte(
  73        struct st_sensor_transfer_buffer *tb, struct device *dev,
  74                        u8 reg_addr, int len, u8 *data, bool multiread_bit)
  75{
  76        return st_sensors_spi_read(tb, dev, reg_addr, len, data, multiread_bit);
  77}
  78
  79static int st_sensors_spi_write_byte(struct st_sensor_transfer_buffer *tb,
  80                                struct device *dev, u8 reg_addr, u8 data)
  81{
  82        int err;
  83
  84        struct spi_transfer xfers = {
  85                .tx_buf = tb->tx_buf,
  86                .bits_per_word = 8,
  87                .len = 2,
  88        };
  89
  90        mutex_lock(&tb->buf_lock);
  91        tb->tx_buf[0] = reg_addr;
  92        tb->tx_buf[1] = data;
  93
  94        err = spi_sync_transfer(to_spi_device(dev), &xfers, 1);
  95        mutex_unlock(&tb->buf_lock);
  96
  97        return err;
  98}
  99
 100static const struct st_sensor_transfer_function st_sensors_tf_spi = {
 101        .read_byte = st_sensors_spi_read_byte,
 102        .write_byte = st_sensors_spi_write_byte,
 103        .read_multiple_byte = st_sensors_spi_read_multiple_byte,
 104};
 105
 106void st_sensors_spi_configure(struct iio_dev *indio_dev,
 107                        struct spi_device *spi, struct st_sensor_data *sdata)
 108{
 109        spi_set_drvdata(spi, indio_dev);
 110
 111        indio_dev->dev.parent = &spi->dev;
 112        indio_dev->name = spi->modalias;
 113
 114        sdata->dev = &spi->dev;
 115        sdata->tf = &st_sensors_tf_spi;
 116        sdata->get_irq_data_ready = st_sensors_spi_get_irq;
 117}
 118EXPORT_SYMBOL(st_sensors_spi_configure);
 119
 120MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 121MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
 122MODULE_LICENSE("GPL v2");
 123