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

   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
  22 static 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
  29 static 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
  61 acc_spi_read_error:
  62         mutex_unlock(&tb->buf_lock);
  63         return err;
  64 }
  65
  66 static 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
  72 static 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
  79 static 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
 100 static 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
 106 void 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 }
 118 EXPORT_SYMBOL(st_sensors_spi_configure);
 119
 120 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 121 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
 122 MODULE_LICENSE("GPL v2");