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/iio/iio.h>
  13 #include <linux/property.h>
  14 #include <linux/regmap.h>
  15 #include <linux/spi/spi.h>
  16
  17 #include <linux/iio/common/st_sensors_spi.h>
  18
  19 #define ST_SENSORS_SPI_MULTIREAD        0xc0
  20
  21 static const struct regmap_config st_sensors_spi_regmap_config = {
  22         .reg_bits = 8,
  23         .val_bits = 8,
  24 };
  25
  26 static const struct regmap_config st_sensors_spi_regmap_multiread_bit_config = {
  27         .reg_bits = 8,
  28         .val_bits = 8,
  29         .read_flag_mask = ST_SENSORS_SPI_MULTIREAD,
  30 };
  31
  32 /*
  33  * st_sensors_is_spi_3_wire() - check if SPI 3-wire mode has been selected
  34  * @spi: spi device reference.
  35  *
  36  * Return: true if SPI 3-wire mode is selected, false otherwise.
  37  */
  38 static bool st_sensors_is_spi_3_wire(struct spi_device *spi)
  39 {
  40         struct st_sensors_platform_data *pdata;
  41         struct device *dev = &spi->dev;
  42
  43         if (device_property_read_bool(dev, "spi-3wire"))
  44                 return true;
  45
  46         pdata = dev_get_platdata(dev);
  47         if (pdata && pdata->spi_3wire)
  48                 return true;
  49
  50         return false;
  51 }
  52
  53 /*
  54  * st_sensors_configure_spi_3_wire() - configure SPI 3-wire if needed
  55  * @spi: spi device reference.
  56  * @settings: sensor specific settings reference.
  57  *
  58  * Return: 0 on success, else a negative error code.
  59  */
  60 static int st_sensors_configure_spi_3_wire(struct spi_device *spi,
  61                                            struct st_sensor_settings *settings)
  62 {
  63         if (settings->sim.addr) {
  64                 u8 buffer[] = {
  65                         settings->sim.addr,
  66                         settings->sim.value
  67                 };
  68
  69                 return spi_write(spi, buffer, 2);
  70         }
  71
  72         return 0;
  73 }
  74
  75 /*
  76  * st_sensors_spi_configure() - configure SPI interface
  77  * @indio_dev: IIO device reference.
  78  * @spi: spi device reference.
  79  *
  80  * Return: 0 on success, else a negative error code.
  81  */
  82 int st_sensors_spi_configure(struct iio_dev *indio_dev,
  83                              struct spi_device *spi)
  84 {
  85         struct st_sensor_data *sdata = iio_priv(indio_dev);
  86         const struct regmap_config *config;
  87         int err;
  88
  89         if (st_sensors_is_spi_3_wire(spi)) {
  90                 err = st_sensors_configure_spi_3_wire(spi,
  91                                                       sdata->sensor_settings);
  92                 if (err < 0)
  93                         return err;
  94         }
  95
  96         if (sdata->sensor_settings->multi_read_bit)
  97                 config = &st_sensors_spi_regmap_multiread_bit_config;
  98         else
  99                 config = &st_sensors_spi_regmap_config;
 100
 101         sdata->regmap = devm_regmap_init_spi(spi, config);
 102         if (IS_ERR(sdata->regmap)) {
 103                 dev_err(&spi->dev, "Failed to register spi regmap (%ld)\n",
 104                         PTR_ERR(sdata->regmap));
 105                 return PTR_ERR(sdata->regmap);
 106         }
 107
 108         spi_set_drvdata(spi, indio_dev);
 109
 110         indio_dev->name = spi->modalias;
 111
 112         sdata->irq = spi->irq;
 113
 114         return 0;
 115 }
 116 EXPORT_SYMBOL_NS(st_sensors_spi_configure, "IIO_ST_SENSORS");
 117
 118 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
 119 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
 120 MODULE_LICENSE("GPL v2");