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");
121