drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c

   1 /*
   2  * STMicroelectronics st_lsm6dsx spi driver
   3  *
   4  * Copyright 2016 STMicroelectronics Inc.
   5  *
   6  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
   7  * Denis Ciocca <denis.ciocca@st.com>
   8  *
   9  * Licensed under the GPL-2.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/slab.h>
  16 #include <linux/of.h>
  17
  18 #include "st_lsm6dsx.h"
  19
  20 #define SENSORS_SPI_READ        BIT(7)
  21
  22 static int st_lsm6dsx_spi_read(struct device *dev, u8 addr, int len,
  23                                u8 *data)
  24 {
  25         struct spi_device *spi = to_spi_device(dev);
  26         struct st_lsm6dsx_hw *hw = spi_get_drvdata(spi);
  27         int err;
  28
  29         struct spi_transfer xfers[] = {
  30                 {
  31                         .tx_buf = hw->tb.tx_buf,
  32                         .bits_per_word = 8,
  33                         .len = 1,
  34                 },
  35                 {
  36                         .rx_buf = hw->tb.rx_buf,
  37                         .bits_per_word = 8,
  38                         .len = len,
  39                 }
  40         };
  41
  42         hw->tb.tx_buf[0] = addr | SENSORS_SPI_READ;
  43
  44         err = spi_sync_transfer(spi, xfers,  ARRAY_SIZE(xfers));
  45         if (err < 0)
  46                 return err;
  47
  48         memcpy(data, hw->tb.rx_buf, len * sizeof(u8));
  49
  50         return len;
  51 }
  52
  53 static int st_lsm6dsx_spi_write(struct device *dev, u8 addr, int len,
  54                                 u8 *data)
  55 {
  56         struct st_lsm6dsx_hw *hw;
  57         struct spi_device *spi;
  58
  59         if (len >= ST_LSM6DSX_TX_MAX_LENGTH)
  60                 return -ENOMEM;
  61
  62         spi = to_spi_device(dev);
  63         hw = spi_get_drvdata(spi);
  64
  65         hw->tb.tx_buf[0] = addr;
  66         memcpy(&hw->tb.tx_buf[1], data, len);
  67
  68         return spi_write(spi, hw->tb.tx_buf, len + 1);
  69 }
  70
  71 static const struct st_lsm6dsx_transfer_function st_lsm6dsx_transfer_fn = {
  72         .read = st_lsm6dsx_spi_read,
  73         .write = st_lsm6dsx_spi_write,
  74 };
  75
  76 static int st_lsm6dsx_spi_probe(struct spi_device *spi)
  77 {
  78         const struct spi_device_id *id = spi_get_device_id(spi);
  79
  80         return st_lsm6dsx_probe(&spi->dev, spi->irq,
  81                                 (int)id->driver_data, id->name,
  82                                 &st_lsm6dsx_transfer_fn);
  83 }
  84
  85 static const struct of_device_id st_lsm6dsx_spi_of_match[] = {
  86         {
  87                 .compatible = "st,lsm6ds3",
  88                 .data = (void *)ST_LSM6DS3_ID,
  89         },
  90         {
  91                 .compatible = "st,lsm6ds3h",
  92                 .data = (void *)ST_LSM6DS3H_ID,
  93         },
  94         {
  95                 .compatible = "st,lsm6dsl",
  96                 .data = (void *)ST_LSM6DSL_ID,
  97         },
  98         {
  99                 .compatible = "st,lsm6dsm",
 100                 .data = (void *)ST_LSM6DSM_ID,
 101         },
 102         {},
 103 };
 104 MODULE_DEVICE_TABLE(of, st_lsm6dsx_spi_of_match);
 105
 106 static const struct spi_device_id st_lsm6dsx_spi_id_table[] = {
 107         { ST_LSM6DS3_DEV_NAME, ST_LSM6DS3_ID },
 108         { ST_LSM6DS3H_DEV_NAME, ST_LSM6DS3H_ID },
 109         { ST_LSM6DSL_DEV_NAME, ST_LSM6DSL_ID },
 110         { ST_LSM6DSM_DEV_NAME, ST_LSM6DSM_ID },
 111         {},
 112 };
 113 MODULE_DEVICE_TABLE(spi, st_lsm6dsx_spi_id_table);
 114
 115 static struct spi_driver st_lsm6dsx_driver = {
 116         .driver = {
 117                 .name = "st_lsm6dsx_spi",
 118                 .pm = &st_lsm6dsx_pm_ops,
 119                 .of_match_table = of_match_ptr(st_lsm6dsx_spi_of_match),
 120         },
 121         .probe = st_lsm6dsx_spi_probe,
 122         .id_table = st_lsm6dsx_spi_id_table,
 123 };
 124 module_spi_driver(st_lsm6dsx_driver);
 125
 126 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
 127 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 128 MODULE_DESCRIPTION("STMicroelectronics st_lsm6dsx spi driver");
 129 MODULE_LICENSE("GPL v2");