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a0386bba70
The value returned by an spi driver's remove function is mostly ignored. (Only an error message is printed if the value is non-zero that the error is ignored.) So change the prototype of the remove function to return no value. This way driver authors are not tempted to assume that passing an error to the upper layer is a good idea. All drivers are adapted accordingly. There is no intended change of behaviour, all callbacks were prepared to return 0 before. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Claudius Heine <ch@denx.de> Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com> Acked-by: Łukasz Stelmach <l.stelmach@samsung.com> Acked-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
106 lines
2.5 KiB
C
106 lines
2.5 KiB
C
// 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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