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0c3a333524
MPL115 supports shutdown gpio which can be used to set the state to low power mode. Power from all internal circuits and registers is removed. This is done by pulling the SHDN pin to low. This patch enables runtime PM on MPL115 to increase power savings. According to spec., a wakeup time period of ~5 ms exists between waking up and actually communicating with the device. This is implemented using sleep delay. Signed-off-by: Rajat Khandelwal <rajat.khandelwal@linux.intel.com> Link: https://lore.kernel.org/r/20221010173720.568916-1-rajat.khandelwal@linux.intel.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Freescale MPL115A1 pressure/temperature sensor
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*
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* Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
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*
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* Datasheet: http://www.nxp.com/files/sensors/doc/data_sheet/MPL115A1.pdf
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*/
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#include <linux/module.h>
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#include <linux/spi/spi.h>
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#include "mpl115.h"
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#define MPL115_SPI_WRITE(address) ((address) << 1)
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#define MPL115_SPI_READ(address) (0x80 | (address) << 1)
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struct mpl115_spi_buf {
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u8 tx[4];
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u8 rx[4];
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};
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static int mpl115_spi_init(struct device *dev)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct mpl115_spi_buf *buf;
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buf = devm_kzalloc(dev, sizeof(*buf), GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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spi_set_drvdata(spi, buf);
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return 0;
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}
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static int mpl115_spi_read(struct device *dev, u8 address)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
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struct spi_transfer xfer = {
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.tx_buf = buf->tx,
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.rx_buf = buf->rx,
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.len = 4,
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};
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int ret;
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buf->tx[0] = MPL115_SPI_READ(address);
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buf->tx[2] = MPL115_SPI_READ(address + 1);
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ret = spi_sync_transfer(spi, &xfer, 1);
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if (ret)
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return ret;
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return (buf->rx[1] << 8) | buf->rx[3];
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}
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static int mpl115_spi_write(struct device *dev, u8 address, u8 value)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct mpl115_spi_buf *buf = spi_get_drvdata(spi);
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struct spi_transfer xfer = {
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.tx_buf = buf->tx,
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.len = 2,
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};
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buf->tx[0] = MPL115_SPI_WRITE(address);
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buf->tx[1] = value;
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return spi_sync_transfer(spi, &xfer, 1);
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}
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static const struct mpl115_ops mpl115_spi_ops = {
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.init = mpl115_spi_init,
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.read = mpl115_spi_read,
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.write = mpl115_spi_write,
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};
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static int mpl115_spi_probe(struct spi_device *spi)
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{
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const struct spi_device_id *id = spi_get_device_id(spi);
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return mpl115_probe(&spi->dev, id->name, &mpl115_spi_ops);
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}
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static const struct spi_device_id mpl115_spi_ids[] = {
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{ "mpl115", 0 },
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{}
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};
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MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
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static struct spi_driver mpl115_spi_driver = {
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.driver = {
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.name = "mpl115",
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.pm = pm_ptr(&mpl115_dev_pm_ops),
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},
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.probe = mpl115_spi_probe,
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.id_table = mpl115_spi_ids,
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};
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module_spi_driver(mpl115_spi_driver);
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MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
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MODULE_DESCRIPTION("Freescale MPL115A1 pressure/temperature driver");
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MODULE_LICENSE("GPL");
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MODULE_IMPORT_NS(IIO_MPL115);
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