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 #include <linux/property.h>
  15 #include <linux/regmap.h>
  16
  17 #include <linux/iio/common/st_sensors_spi.h>
  18 #include "st_sensors_core.h"
  19
  20 #define ST_SENSORS_SPI_MULTIREAD        0xc0
  21
  22 static const struct regmap_config st_sensors_spi_regmap_config = {
  23         .reg_bits = 8,
  24         .val_bits = 8,
  25 };
  26
  27 static const struct regmap_config st_sensors_spi_regmap_multiread_bit_config = {
  28         .reg_bits = 8,
  29         .val_bits = 8,
  30         .read_flag_mask = ST_SENSORS_SPI_MULTIREAD,
  31 };
  32
  33 /*
  34  * st_sensors_is_spi_3_wire() - check if SPI 3-wire mode has been selected
  35  * @spi: spi device reference.
  36  *
  37  * Return: true if SPI 3-wire mode is selected, false otherwise.
  38  */
  39 static bool st_sensors_is_spi_3_wire(struct spi_device *spi)
  40 {
  41         struct st_sensors_platform_data *pdata;
  42         struct device *dev = &spi->dev;
  43
  44         if (device_property_read_bool(dev, "spi-3wire"))
  45                 return true;
  46
  47         pdata = (struct st_sensors_platform_data *)dev->platform_data;
  48         if (pdata && pdata->spi_3wire)
  49                 return true;
  50
  51         return false;
  52 }
  53
  54 /*
  55  * st_sensors_configure_spi_3_wire() - configure SPI 3-wire if needed
  56  * @spi: spi device reference.
  57  * @settings: sensor specific settings reference.
  58  *
  59  * Return: 0 on success, else a negative error code.
  60  */
  61 static int st_sensors_configure_spi_3_wire(struct spi_device *spi,
  62                                            struct st_sensor_settings *settings)
  63 {
  64         if (settings->sim.addr) {
  65                 u8 buffer[] = {
  66                         settings->sim.addr,
  67                         settings->sim.value
  68                 };
  69
  70                 return spi_write(spi, buffer, 2);
  71         }
  72
  73         return 0;
  74 }
  75
  76 /*
  77  * st_sensors_spi_configure() - configure SPI interface
  78  * @indio_dev: IIO device reference.
  79  * @spi: spi device reference.
  80  *
  81  * Return: 0 on success, else a negative error code.
  82  */
  83 int st_sensors_spi_configure(struct iio_dev *indio_dev,
  84                              struct spi_device *spi)
  85 {
  86         struct st_sensor_data *sdata = iio_priv(indio_dev);
  87         const struct regmap_config *config;
  88         int err;
  89
  90         if (st_sensors_is_spi_3_wire(spi)) {
  91                 err = st_sensors_configure_spi_3_wire(spi,
  92                                                       sdata->sensor_settings);
  93                 if (err < 0)
  94                         return err;
  95         }
  96
  97         if (sdata->sensor_settings->multi_read_bit)
  98                 config = &st_sensors_spi_regmap_multiread_bit_config;
  99         else
 100                 config = &st_sensors_spi_regmap_config;
 101
 102         sdata->regmap = devm_regmap_init_spi(spi, config);
 103         if (IS_ERR(sdata->regmap)) {
 104                 dev_err(&spi->dev, "Failed to register spi regmap (%d)\n",
 105                         (int)PTR_ERR(sdata->regmap));
 106                 return PTR_ERR(sdata->regmap);
 107         }
 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->irq = spi->irq;
 116
 117         return 0;
 118 }
 119 EXPORT_SYMBOL(st_sensors_spi_configure);
 120
 121 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 122 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
 123 MODULE_LICENSE("GPL v2");