107 lines
2.5 KiB
C
107 lines
2.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC
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*
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* Based on ltc2497.c which has
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* Copyright (C) 2017 Analog Devices Inc.
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*
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* Licensed under the GPL-2.
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*
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* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf
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*/
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#include <linux/spi/spi.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/driver.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include "ltc2497.h"
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struct ltc2496_driverdata {
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/* this must be the first member */
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struct ltc2497core_driverdata common_ddata;
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struct spi_device *spi;
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/*
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* DMA (thus cache coherency maintenance) requires the
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* transfer buffers to live in their own cache lines.
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*/
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unsigned char rxbuf[3] ____cacheline_aligned;
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unsigned char txbuf[3];
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};
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static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata,
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u8 address, int *val)
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{
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struct ltc2496_driverdata *st =
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container_of(ddata, struct ltc2496_driverdata, common_ddata);
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struct spi_transfer t = {
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.tx_buf = st->txbuf,
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.rx_buf = st->rxbuf,
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.len = sizeof(st->txbuf),
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};
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int ret;
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st->txbuf[0] = LTC2497_ENABLE | address;
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ret = spi_sync_transfer(st->spi, &t, 1);
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if (ret < 0) {
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dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n",
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ERR_PTR(ret));
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return ret;
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}
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if (val)
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*val = ((st->rxbuf[0] & 0x3f) << 12 |
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st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) -
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(1 << 17);
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return 0;
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}
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static int ltc2496_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct ltc2496_driverdata *st;
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struct device *dev = &spi->dev;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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spi_set_drvdata(spi, indio_dev);
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st->spi = spi;
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st->common_ddata.result_and_measure = ltc2496_result_and_measure;
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return ltc2497core_probe(dev, indio_dev);
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}
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static void ltc2496_remove(struct spi_device *spi)
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{
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struct iio_dev *indio_dev = spi_get_drvdata(spi);
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ltc2497core_remove(indio_dev);
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}
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static const struct of_device_id ltc2496_of_match[] = {
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{ .compatible = "lltc,ltc2496", },
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{},
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};
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MODULE_DEVICE_TABLE(of, ltc2496_of_match);
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static struct spi_driver ltc2496_driver = {
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.driver = {
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.name = "ltc2496",
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.of_match_table = ltc2496_of_match,
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},
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.probe = ltc2496_probe,
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.remove = ltc2496_remove,
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};
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module_spi_driver(ltc2496_driver);
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MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>");
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MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver");
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MODULE_LICENSE("GPL v2");
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