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"); 121