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         struct spi_message msg;
  33         int err;
  34
  35         struct spi_transfer xfers[] = {
  36                 {
  37                         .tx_buf = tb->tx_buf,
  38                         .bits_per_word = 8,
  39                         .len = 1,
  40                 },
  41                 {
  42                         .rx_buf = tb->rx_buf,
  43                         .bits_per_word = 8,
  44                         .len = len,
  45                 }
  46         };
  47
  48         mutex_lock(&tb->buf_lock);
  49         if ((multiread_bit) && (len > 1))
  50                 tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_MULTIREAD;
  51         else
  52                 tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_READ;
  53
  54         spi_message_init(&msg);
  55         spi_message_add_tail(&xfers[0], &msg);
  56         spi_message_add_tail(&xfers[1], &msg);
  57         err = spi_sync(to_spi_device(dev), &msg);
  58         if (err)
  59                 goto acc_spi_read_error;
  60
  61         memcpy(data, tb->rx_buf, len*sizeof(u8));
  62         mutex_unlock(&tb->buf_lock);
  63         return len;
  64
  65 acc_spi_read_error:
  66         mutex_unlock(&tb->buf_lock);
  67         return err;
  68 }
  69
  70 static int st_sensors_spi_read_byte(struct st_sensor_transfer_buffer *tb,
  71                                 struct device *dev, u8 reg_addr, u8 *res_byte)
  72 {
  73         return st_sensors_spi_read(tb, dev, reg_addr, 1, res_byte, false);
  74 }
  75
  76 static int st_sensors_spi_read_multiple_byte(
  77         struct st_sensor_transfer_buffer *tb, struct device *dev,
  78                         u8 reg_addr, int len, u8 *data, bool multiread_bit)
  79 {
  80         return st_sensors_spi_read(tb, dev, reg_addr, len, data, multiread_bit);
  81 }
  82
  83 static int st_sensors_spi_write_byte(struct st_sensor_transfer_buffer *tb,
  84                                 struct device *dev, u8 reg_addr, u8 data)
  85 {
  86         struct spi_message msg;
  87         int err;
  88
  89         struct spi_transfer xfers = {
  90                 .tx_buf = tb->tx_buf,
  91                 .bits_per_word = 8,
  92                 .len = 2,
  93         };
  94
  95         mutex_lock(&tb->buf_lock);
  96         tb->tx_buf[0] = reg_addr;
  97         tb->tx_buf[1] = data;
  98
  99         spi_message_init(&msg);
 100         spi_message_add_tail(&xfers, &msg);
 101         err = spi_sync(to_spi_device(dev), &msg);
 102         mutex_unlock(&tb->buf_lock);
 103
 104         return err;
 105 }
 106
 107 static const struct st_sensor_transfer_function st_sensors_tf_spi = {
 108         .read_byte = st_sensors_spi_read_byte,
 109         .write_byte = st_sensors_spi_write_byte,
 110         .read_multiple_byte = st_sensors_spi_read_multiple_byte,
 111 };
 112
 113 void st_sensors_spi_configure(struct iio_dev *indio_dev,
 114                         struct spi_device *spi, struct st_sensor_data *sdata)
 115 {
 116         spi_set_drvdata(spi, indio_dev);
 117
 118         indio_dev->dev.parent = &spi->dev;
 119         indio_dev->name = spi->modalias;
 120
 121         sdata->tf = &st_sensors_tf_spi;
 122         sdata->get_irq_data_ready = st_sensors_spi_get_irq;
 123 }
 124 EXPORT_SYMBOL(st_sensors_spi_configure);
 125
 126 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 127 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
 128 MODULE_LICENSE("GPL v2");