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
 21static const struct regmap_config st_sensors_spi_regmap_config = {
 22	.reg_bits = 8,
 23	.val_bits = 8,
 24};
 25
 26static 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 */
 38static 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 */
 60static 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 */
 82int 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}
116EXPORT_SYMBOL_NS(st_sensors_spi_configure, "IIO_ST_SENSORS");
117
118MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
119MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
120MODULE_LICENSE("GPL v2");