1 /* 2 * Freescale MPL115A1 pressure/temperature sensor 3 * 4 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com> 5 * 6 * This file is subject to the terms and conditions of version 2 of 7 * the GNU General Public License. See the file COPYING in the main 8 * directory of this archive for more details. 9 * 10 * Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf 11 */ 12 13 #include <linux/module.h> 14 #include <linux/spi/spi.h> 15 16 #include "mpl115.h" 17 18 #define MPL115_SPI_WRITE(address) ((address) << 1) 19 #define MPL115_SPI_READ(address) (0x80 | (address) << 1) 20 21 struct mpl115_spi_buf { 22 u8 tx[4]; 23 u8 rx[4]; 24 }; 25 26 static int mpl115_spi_init(struct device *dev) 27 { 28 struct spi_device *spi = to_spi_device(dev); 29 struct mpl115_spi_buf *buf; 30 31 buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL); 32 if (!buf) 33 return -ENOMEM; 34 35 spi_set_drvdata(spi, buf); 36 37 return 0; 38 } 39 40 static int mpl115_spi_read(struct device *dev, u8 address) 41 { 42 struct spi_device *spi = to_spi_device(dev); 43 struct mpl115_spi_buf *buf = spi_get_drvdata(spi); 44 struct spi_transfer xfer = { 45 .tx_buf = buf->tx, 46 .rx_buf = buf->rx, 47 .len = 4, 48 }; 49 int ret; 50 51 buf->tx[0] = MPL115_SPI_READ(address); 52 buf->tx[2] = MPL115_SPI_READ(address + 1); 53 54 ret = spi_sync_transfer(spi, &xfer, 1); 55 if (ret) 56 return ret; 57 58 return (buf->rx[1] << 8) | buf->rx[3]; 59 } 60 61 static int mpl115_spi_write(struct device *dev, u8 address, u8 value) 62 { 63 struct spi_device *spi = to_spi_device(dev); 64 struct mpl115_spi_buf *buf = spi_get_drvdata(spi); 65 struct spi_transfer xfer = { 66 .tx_buf = buf->tx, 67 .len = 2, 68 }; 69 70 buf->tx[0] = MPL115_SPI_WRITE(address); 71 buf->tx[1] = value; 72 73 return spi_sync_transfer(spi, &xfer, 1); 74 } 75 76 static const struct mpl115_ops mpl115_spi_ops = { 77 .init = mpl115_spi_init, 78 .read = mpl115_spi_read, 79 .write = mpl115_spi_write, 80 }; 81 82 static int mpl115_spi_probe(struct spi_device *spi) 83 { 84 const struct spi_device_id *id = spi_get_device_id(spi); 85 86 return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops); 87 } 88 89 static const struct spi_device_id mpl115_spi_ids[] = { 90 { "mpl115", 0 }, 91 {} 92 }; 93 MODULE_DEVICE_TABLE(spi, mpl115_spi_ids); 94 95 static struct spi_driver mpl115_spi_driver = { 96 .driver = { 97 .name = "mpl115", 98 }, 99 .probe = mpl115_spi_probe, 100 .id_table = mpl115_spi_ids, 101 }; 102 module_spi_driver(mpl115_spi_driver); 103 104 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 105 MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver"); 106 MODULE_LICENSE("GPL"); 107