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/regmap.h>
15 
16 #include <linux/iio/common/st_sensors_spi.h>
17 #include "st_sensors_core.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 device_node *np = spi->dev.of_node;
41 	struct st_sensors_platform_data *pdata;
42 
43 	pdata = (struct st_sensors_platform_data *)spi->dev.platform_data;
44 	if ((np && of_property_read_bool(np, "spi-3wire")) ||
45 	    (pdata && pdata->spi_3wire)) {
46 		return true;
47 	}
48 
49 	return false;
50 }
51 
52 /*
53  * st_sensors_configure_spi_3_wire() - configure SPI 3-wire if needed
54  * @spi: spi device reference.
55  * @settings: sensor specific settings reference.
56  *
57  * Return: 0 on success, else a negative error code.
58  */
59 static int st_sensors_configure_spi_3_wire(struct spi_device *spi,
60 					   struct st_sensor_settings *settings)
61 {
62 	if (settings->sim.addr) {
63 		u8 buffer[] = {
64 			settings->sim.addr,
65 			settings->sim.value
66 		};
67 
68 		return spi_write(spi, buffer, 2);
69 	}
70 
71 	return 0;
72 }
73 
74 /*
75  * st_sensors_spi_configure() - configure SPI interface
76  * @indio_dev: IIO device reference.
77  * @spi: spi device reference.
78  *
79  * Return: 0 on success, else a negative error code.
80  */
81 int st_sensors_spi_configure(struct iio_dev *indio_dev,
82 			     struct spi_device *spi)
83 {
84 	struct st_sensor_data *sdata = iio_priv(indio_dev);
85 	const struct regmap_config *config;
86 	int err;
87 
88 	if (st_sensors_is_spi_3_wire(spi)) {
89 		err = st_sensors_configure_spi_3_wire(spi,
90 						      sdata->sensor_settings);
91 		if (err < 0)
92 			return err;
93 	}
94 
95 	if (sdata->sensor_settings->multi_read_bit)
96 		config = &st_sensors_spi_regmap_multiread_bit_config;
97 	else
98 		config = &st_sensors_spi_regmap_config;
99 
100 	sdata->regmap = devm_regmap_init_spi(spi, config);
101 	if (IS_ERR(sdata->regmap)) {
102 		dev_err(&spi->dev, "Failed to register spi regmap (%d)\n",
103 			(int)PTR_ERR(sdata->regmap));
104 		return PTR_ERR(sdata->regmap);
105 	}
106 
107 	spi_set_drvdata(spi, indio_dev);
108 
109 	indio_dev->dev.parent = &spi->dev;
110 	indio_dev->name = spi->modalias;
111 
112 	sdata->dev = &spi->dev;
113 	sdata->irq = spi->irq;
114 
115 	return 0;
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");
122