f8d4e637cc
commit 90826e08468ba7fb35d8b39645b22d9e80004afe upstream.
The current implementation attempts to recover from an eventual glitch
in the clock by checking frstdata state after reading the first
channel's sample: If frstdata is low, it will reset the chip and
return -EIO.
This will only work in parallel mode, where frstdata pin is set low
after the 2nd sample read starts.
For the serial mode, according to the datasheet, "The FRSTDATA output
returns to a logic low following the 16th SCLK falling edge.", thus
after the Xth pulse, X being the number of bits in a sample, the check
will always be true, and the driver will not work at all in serial
mode if frstdata(optional) is defined in the devicetree as it will
reset the chip, and return -EIO every time read_sample is called.
Hence, this check must be removed for serial mode.
Fixes: b9618c0cac ("staging: IIO: ADC: New driver for AD7606/AD7606-6/AD7606-4")
Signed-off-by: Guillaume Stols <gstols@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240702-cleanup-ad7606-v3-1-18d5ea18770e@baylibre.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
148 lines
4.0 KiB
C
148 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* AD7606 Parallel Interface ADC driver
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*
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* Copyright 2011 Analog Devices Inc.
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*/
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/gpio/consumer.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/iio/iio.h>
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#include "ad7606.h"
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static int ad7606_par16_read_block(struct device *dev,
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int count, void *buf)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct ad7606_state *st = iio_priv(indio_dev);
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/*
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* On the parallel interface, the frstdata signal is set to high while
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* and after reading the sample of the first channel and low for all
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* other channels. This can be used to check that the incoming data is
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* correctly aligned. During normal operation the data should never
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* become unaligned, but some glitch or electrostatic discharge might
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* cause an extra read or clock cycle. Monitoring the frstdata signal
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* allows to recover from such failure situations.
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*/
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int num = count;
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u16 *_buf = buf;
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if (st->gpio_frstdata) {
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insw((unsigned long)st->base_address, _buf, 1);
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if (!gpiod_get_value(st->gpio_frstdata)) {
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ad7606_reset(st);
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return -EIO;
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}
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_buf++;
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num--;
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}
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insw((unsigned long)st->base_address, _buf, num);
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return 0;
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}
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static const struct ad7606_bus_ops ad7606_par16_bops = {
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.read_block = ad7606_par16_read_block,
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};
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static int ad7606_par8_read_block(struct device *dev,
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int count, void *buf)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct ad7606_state *st = iio_priv(indio_dev);
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/*
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* On the parallel interface, the frstdata signal is set to high while
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* and after reading the sample of the first channel and low for all
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* other channels. This can be used to check that the incoming data is
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* correctly aligned. During normal operation the data should never
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* become unaligned, but some glitch or electrostatic discharge might
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* cause an extra read or clock cycle. Monitoring the frstdata signal
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* allows to recover from such failure situations.
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*/
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int num = count;
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u16 *_buf = buf;
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if (st->gpio_frstdata) {
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insb((unsigned long)st->base_address, _buf, 2);
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if (!gpiod_get_value(st->gpio_frstdata)) {
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ad7606_reset(st);
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return -EIO;
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}
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_buf++;
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num--;
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}
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insb((unsigned long)st->base_address, _buf, num * 2);
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return 0;
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}
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static const struct ad7606_bus_ops ad7606_par8_bops = {
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.read_block = ad7606_par8_read_block,
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};
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static int ad7606_par_probe(struct platform_device *pdev)
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{
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const struct platform_device_id *id = platform_get_device_id(pdev);
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struct resource *res;
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void __iomem *addr;
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resource_size_t remap_size;
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int irq;
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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return irq;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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addr = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(addr))
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return PTR_ERR(addr);
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remap_size = resource_size(res);
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return ad7606_probe(&pdev->dev, irq, addr,
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id->name, id->driver_data,
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remap_size > 1 ? &ad7606_par16_bops :
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&ad7606_par8_bops);
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}
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static const struct platform_device_id ad7606_driver_ids[] = {
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{ .name = "ad7605-4", .driver_data = ID_AD7605_4, },
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{ .name = "ad7606-4", .driver_data = ID_AD7606_4, },
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{ .name = "ad7606-6", .driver_data = ID_AD7606_6, },
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{ .name = "ad7606-8", .driver_data = ID_AD7606_8, },
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{ }
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};
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MODULE_DEVICE_TABLE(platform, ad7606_driver_ids);
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static const struct of_device_id ad7606_of_match[] = {
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{ .compatible = "adi,ad7605-4" },
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{ .compatible = "adi,ad7606-4" },
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{ .compatible = "adi,ad7606-6" },
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{ .compatible = "adi,ad7606-8" },
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{ },
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};
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MODULE_DEVICE_TABLE(of, ad7606_of_match);
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static struct platform_driver ad7606_driver = {
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.probe = ad7606_par_probe,
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.id_table = ad7606_driver_ids,
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.driver = {
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.name = "ad7606",
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.pm = AD7606_PM_OPS,
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.of_match_table = ad7606_of_match,
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},
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};
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module_platform_driver(ad7606_driver);
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MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
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MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
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MODULE_LICENSE("GPL v2");
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MODULE_IMPORT_NS(IIO_AD7606);
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