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108 lines
2.5 KiB
108 lines
2.5 KiB
// 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 int 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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return 0; |
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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-kö[email protected]>"); |
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MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver"); |
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MODULE_LICENSE("GPL v2");
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