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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 | // SPDX-License-Identifier: GPL-2.0 /* * BME680 - SPI Driver * * Copyright (C) 2018 Himanshu Jha <himanshujha199640@gmail.com> */ #include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/regmap.h> #include <linux/spi/spi.h> #include "bme680.h" struct bme680_spi_bus_context { struct spi_device *spi; u8 current_page; }; /* * In SPI mode there are only 7 address bits, a "page" register determines * which part of the 8-bit range is active. This function looks at the address * and writes the page selection bit if needed */ static int bme680_regmap_spi_select_page( struct bme680_spi_bus_context *ctx, u8 reg) { struct spi_device *spi = ctx->spi; int ret; u8 buf[2]; u8 page = (reg & 0x80) ? 0 : 1; /* Page "1" is low range */ if (page == ctx->current_page) return 0; /* * Data sheet claims we're only allowed to change bit 4, so we must do * a read-modify-write on each and every page select */ buf[0] = BME680_REG_STATUS; ret = spi_write_then_read(spi, buf, 1, buf + 1, 1); if (ret < 0) { dev_err(&spi->dev, "failed to set page %u\n", page); return ret; } buf[0] = BME680_REG_STATUS; if (page) buf[1] |= BME680_SPI_MEM_PAGE_BIT; else buf[1] &= ~BME680_SPI_MEM_PAGE_BIT; ret = spi_write(spi, buf, 2); if (ret < 0) { dev_err(&spi->dev, "failed to set page %u\n", page); return ret; } ctx->current_page = page; return 0; } static int bme680_regmap_spi_write(void *context, const void *data, size_t count) { struct bme680_spi_bus_context *ctx = context; struct spi_device *spi = ctx->spi; int ret; u8 buf[2]; memcpy(buf, data, 2); ret = bme680_regmap_spi_select_page(ctx, buf[0]); if (ret) return ret; /* * The SPI register address (= full register address without bit 7) * and the write command (bit7 = RW = '0') */ buf[0] &= ~0x80; return spi_write(spi, buf, 2); } static int bme680_regmap_spi_read(void *context, const void *reg, size_t reg_size, void *val, size_t val_size) { struct bme680_spi_bus_context *ctx = context; struct spi_device *spi = ctx->spi; int ret; u8 addr = *(const u8 *)reg; ret = bme680_regmap_spi_select_page(ctx, addr); if (ret) return ret; addr |= 0x80; /* bit7 = RW = '1' */ return spi_write_then_read(spi, &addr, 1, val, val_size); } static struct regmap_bus bme680_regmap_bus = { .write = bme680_regmap_spi_write, .read = bme680_regmap_spi_read, .reg_format_endian_default = REGMAP_ENDIAN_BIG, .val_format_endian_default = REGMAP_ENDIAN_BIG, }; static int bme680_spi_probe(struct spi_device *spi) { const struct spi_device_id *id = spi_get_device_id(spi); struct bme680_spi_bus_context *bus_context; struct regmap *regmap; int ret; spi->bits_per_word = 8; ret = spi_setup(spi); if (ret < 0) { dev_err(&spi->dev, "spi_setup failed!\n"); return ret; } bus_context = devm_kzalloc(&spi->dev, sizeof(*bus_context), GFP_KERNEL); if (!bus_context) return -ENOMEM; bus_context->spi = spi; bus_context->current_page = 0xff; /* Undefined on warm boot */ regmap = devm_regmap_init(&spi->dev, &bme680_regmap_bus, bus_context, &bme680_regmap_config); if (IS_ERR(regmap)) { dev_err(&spi->dev, "Failed to register spi regmap %ld\n", PTR_ERR(regmap)); return PTR_ERR(regmap); } return bme680_core_probe(&spi->dev, regmap, id->name); } static const struct spi_device_id bme680_spi_id[] = { {"bme680", 0}, {}, }; MODULE_DEVICE_TABLE(spi, bme680_spi_id); static const struct of_device_id bme680_of_spi_match[] = { { .compatible = "bosch,bme680", }, {}, }; MODULE_DEVICE_TABLE(of, bme680_of_spi_match); static struct spi_driver bme680_spi_driver = { .driver = { .name = "bme680_spi", .of_match_table = bme680_of_spi_match, }, .probe = bme680_spi_probe, .id_table = bme680_spi_id, }; module_spi_driver(bme680_spi_driver); MODULE_AUTHOR("Himanshu Jha <himanshujha199640@gmail.com>"); MODULE_DESCRIPTION("Bosch BME680 SPI driver"); MODULE_LICENSE("GPL v2"); MODULE_IMPORT_NS(IIO_BME680); |