cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

ltc2496.c (2545B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC
      4 *
      5 * Based on ltc2497.c which has
      6 * Copyright (C) 2017 Analog Devices Inc.
      7 *
      8 * Licensed under the GPL-2.
      9 *
     10 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf
     11 */
     12
     13#include <linux/spi/spi.h>
     14#include <linux/iio/iio.h>
     15#include <linux/iio/driver.h>
     16#include <linux/module.h>
     17#include <linux/mod_devicetable.h>
     18
     19#include "ltc2497.h"
     20
     21struct ltc2496_driverdata {
     22	/* this must be the first member */
     23	struct ltc2497core_driverdata common_ddata;
     24	struct spi_device *spi;
     25
     26	/*
     27	 * DMA (thus cache coherency maintenance) requires the
     28	 * transfer buffers to live in their own cache lines.
     29	 */
     30	unsigned char rxbuf[3] ____cacheline_aligned;
     31	unsigned char txbuf[3];
     32};
     33
     34static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata,
     35				      u8 address, int *val)
     36{
     37	struct ltc2496_driverdata *st =
     38		container_of(ddata, struct ltc2496_driverdata, common_ddata);
     39	struct spi_transfer t = {
     40		.tx_buf = st->txbuf,
     41		.rx_buf = st->rxbuf,
     42		.len = sizeof(st->txbuf),
     43	};
     44	int ret;
     45
     46	st->txbuf[0] = LTC2497_ENABLE | address;
     47
     48	ret = spi_sync_transfer(st->spi, &t, 1);
     49	if (ret < 0)  {
     50		dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n",
     51			ERR_PTR(ret));
     52		return ret;
     53	}
     54
     55	if (val)
     56		*val = ((st->rxbuf[0] & 0x3f) << 12 |
     57			st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) -
     58			(1 << 17);
     59
     60	return 0;
     61}
     62
     63static int ltc2496_probe(struct spi_device *spi)
     64{
     65	struct iio_dev *indio_dev;
     66	struct ltc2496_driverdata *st;
     67	struct device *dev = &spi->dev;
     68
     69	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
     70	if (!indio_dev)
     71		return -ENOMEM;
     72
     73	st = iio_priv(indio_dev);
     74	spi_set_drvdata(spi, indio_dev);
     75	st->spi = spi;
     76	st->common_ddata.result_and_measure = ltc2496_result_and_measure;
     77
     78	return ltc2497core_probe(dev, indio_dev);
     79}
     80
     81static void ltc2496_remove(struct spi_device *spi)
     82{
     83	struct iio_dev *indio_dev = spi_get_drvdata(spi);
     84
     85	ltc2497core_remove(indio_dev);
     86}
     87
     88static const struct of_device_id ltc2496_of_match[] = {
     89	{ .compatible = "lltc,ltc2496", },
     90	{},
     91};
     92MODULE_DEVICE_TABLE(of, ltc2496_of_match);
     93
     94static struct spi_driver ltc2496_driver = {
     95	.driver = {
     96		.name = "ltc2496",
     97		.of_match_table = ltc2496_of_match,
     98	},
     99	.probe = ltc2496_probe,
    100	.remove = ltc2496_remove,
    101};
    102module_spi_driver(ltc2496_driver);
    103
    104MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>");
    105MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver");
    106MODULE_LICENSE("GPL v2");