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