1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Freescale MPL115A1 pressure/temperature sensor 4 * 5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com> 6 * 7 * Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf 8 */ 9 10 #include <linux/module.h> 11 #include <linux/spi/spi.h> 12 13 #include "mpl115.h" 14 15 #define MPL115_SPI_WRITE(address) ((address) << 1) 16 #define MPL115_SPI_READ(address) (0x80 | (address) << 1) 17 18 struct mpl115_spi_buf { 19 u8 tx[4]; 20 u8 rx[4]; 21 }; 22 23 static int mpl115_spi_init(struct device *dev) 24 { 25 struct spi_device *spi = to_spi_device(dev); 26 struct mpl115_spi_buf *buf; 27 28 buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL); 29 if (!buf) 30 return -ENOMEM; 31 32 spi_set_drvdata(spi, buf); 33 34 return 0; 35 } 36 37 static int mpl115_spi_read(struct device *dev, u8 address) 38 { 39 struct spi_device *spi = to_spi_device(dev); 40 struct mpl115_spi_buf *buf = spi_get_drvdata(spi); 41 struct spi_transfer xfer = { 42 .tx_buf = buf->tx, 43 .rx_buf = buf->rx, 44 .len = 4, 45 }; 46 int ret; 47 48 buf->tx[0] = MPL115_SPI_READ(address); 49 buf->tx[2] = MPL115_SPI_READ(address + 1); 50 51 ret = spi_sync_transfer(spi, &xfer, 1); 52 if (ret) 53 return ret; 54 55 return (buf->rx[1] << 8) | buf->rx[3]; 56 } 57 58 static int mpl115_spi_write(struct device *dev, u8 address, u8 value) 59 { 60 struct spi_device *spi = to_spi_device(dev); 61 struct mpl115_spi_buf *buf = spi_get_drvdata(spi); 62 struct spi_transfer xfer = { 63 .tx_buf = buf->tx, 64 .len = 2, 65 }; 66 67 buf->tx[0] = MPL115_SPI_WRITE(address); 68 buf->tx[1] = value; 69 70 return spi_sync_transfer(spi, &xfer, 1); 71 } 72 73 static const struct mpl115_ops mpl115_spi_ops = { 74 .init = mpl115_spi_init, 75 .read = mpl115_spi_read, 76 .write = mpl115_spi_write, 77 }; 78 79 static int mpl115_spi_probe(struct spi_device *spi) 80 { 81 const struct spi_device_id *id = spi_get_device_id(spi); 82 83 return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops); 84 } 85 86 static const struct spi_device_id mpl115_spi_ids[] = { 87 { "mpl115", 0 }, 88 {} 89 }; 90 MODULE_DEVICE_TABLE(spi, mpl115_spi_ids); 91 92 static struct spi_driver mpl115_spi_driver = { 93 .driver = { 94 .name = "mpl115", 95 }, 96 .probe = mpl115_spi_probe, 97 .id_table = mpl115_spi_ids, 98 }; 99 module_spi_driver(mpl115_spi_driver); 100 101 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 102 MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver"); 103 MODULE_LICENSE("GPL"); 104