drivers/iio/common/st_sensors/st_sensors_spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * STMicroelectronics sensors spi library driver
   4  *
   5  * Copyright 2012-2013 STMicroelectronics Inc.
   6  *
   7  * Denis Ciocca <denis.ciocca@st.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/iio/iio.h>
  14
  15 #include <linux/iio/common/st_sensors_spi.h>
  16
  17
  18 #define ST_SENSORS_SPI_MULTIREAD        0xc0
  19 #define ST_SENSORS_SPI_READ             0x80
  20
  21 static unsigned int st_sensors_spi_get_irq(struct iio_dev *indio_dev)
  22 {
  23         struct st_sensor_data *sdata = iio_priv(indio_dev);
  24
  25         return to_spi_device(sdata->dev)->irq;
  26 }
  27
  28 static int st_sensors_spi_read(struct st_sensor_transfer_buffer *tb,
  29         struct device *dev, u8 reg_addr, int len, u8 *data, bool multiread_bit)
  30 {
  31         int err;
  32
  33         struct spi_transfer xfers[] = {
  34                 {
  35                         .tx_buf = tb->tx_buf,
  36                         .bits_per_word = 8,
  37                         .len = 1,
  38                 },
  39                 {
  40                         .rx_buf = tb->rx_buf,
  41                         .bits_per_word = 8,
  42                         .len = len,
  43                 }
  44         };
  45
  46         mutex_lock(&tb->buf_lock);
  47         if ((multiread_bit) && (len > 1))
  48                 tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_MULTIREAD;
  49         else
  50                 tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_READ;
  51
  52         err = spi_sync_transfer(to_spi_device(dev), xfers, ARRAY_SIZE(xfers));
  53         if (err)
  54                 goto acc_spi_read_error;
  55
  56         memcpy(data, tb->rx_buf, len);
  57         mutex_unlock(&tb->buf_lock);
  58         return len;
  59
  60 acc_spi_read_error:
  61         mutex_unlock(&tb->buf_lock);
  62         return err;
  63 }
  64
  65 static int st_sensors_spi_read_byte(struct st_sensor_transfer_buffer *tb,
  66                                 struct device *dev, u8 reg_addr, u8 *res_byte)
  67 {
  68         return st_sensors_spi_read(tb, dev, reg_addr, 1, res_byte, false);
  69 }
  70
  71 static int st_sensors_spi_read_multiple_byte(
  72         struct st_sensor_transfer_buffer *tb, struct device *dev,
  73                         u8 reg_addr, int len, u8 *data, bool multiread_bit)
  74 {
  75         return st_sensors_spi_read(tb, dev, reg_addr, len, data, multiread_bit);
  76 }
  77
  78 static int st_sensors_spi_write_byte(struct st_sensor_transfer_buffer *tb,
  79                                 struct device *dev, u8 reg_addr, u8 data)
  80 {
  81         int err;
  82
  83         struct spi_transfer xfers = {
  84                 .tx_buf = tb->tx_buf,
  85                 .bits_per_word = 8,
  86                 .len = 2,
  87         };
  88
  89         mutex_lock(&tb->buf_lock);
  90         tb->tx_buf[0] = reg_addr;
  91         tb->tx_buf[1] = data;
  92
  93         err = spi_sync_transfer(to_spi_device(dev), &xfers, 1);
  94         mutex_unlock(&tb->buf_lock);
  95
  96         return err;
  97 }
  98
  99 static const struct st_sensor_transfer_function st_sensors_tf_spi = {
 100         .read_byte = st_sensors_spi_read_byte,
 101         .write_byte = st_sensors_spi_write_byte,
 102         .read_multiple_byte = st_sensors_spi_read_multiple_byte,
 103 };
 104
 105 void st_sensors_spi_configure(struct iio_dev *indio_dev,
 106                         struct spi_device *spi, struct st_sensor_data *sdata)
 107 {
 108         spi_set_drvdata(spi, indio_dev);
 109
 110         indio_dev->dev.parent = &spi->dev;
 111         indio_dev->name = spi->modalias;
 112
 113         sdata->dev = &spi->dev;
 114         sdata->tf = &st_sensors_tf_spi;
 115         sdata->get_irq_data_ready = st_sensors_spi_get_irq;
 116 }
 117 EXPORT_SYMBOL(st_sensors_spi_configure);
 118
 119 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 120 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
 121 MODULE_LICENSE("GPL v2");