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 */
st_sensors_is_spi_3_wire(struct spi_device * spi)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 */
st_sensors_configure_spi_3_wire(struct spi_device * spi,struct st_sensor_settings * settings)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 */
st_sensors_spi_configure(struct iio_dev * indio_dev,struct spi_device * spi)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");
121