Commit d97d11c7 authored by David Lechner's avatar David Lechner Committed by Jonathan Cameron
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staging: iio: resolver: ad2s1210: do not use fault register for dummy read 



When reading registers on the AD2S1210 chip, we have to supply a "dummy"
address for the second SPI tx byte so that we don't accidentally write
to a register. This register will be read and the value discarded on the
next regmap read or write call.

Reading the fault register has a side-effect of clearing the faults
so we should not use this register for the dummy read.

Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231005-ad2s1210-mainline-v4-1-ec00746840fc@baylibre.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 6eb14ffa

drivers/staging/iio/resolver/ad2s1210.c

+3 −2
Original line number Diff line number Diff line
@@ -166,9 +166,10 @@ static int ad2s1210_regmap_reg_read(void *context, unsigned int reg, 
	st->tx[0] = reg;

	/*

	 * Must be valid register address here otherwise this could write data.

	 * It doesn't matter which one.

	 * It doesn't matter which one as long as reading doesn't have side-

	 * effects.

	 */

	st->tx[1] = AD2S1210_REG_FAULT;

	st->tx[1] = AD2S1210_REG_CONTROL;



	ret = spi_sync_transfer(st->sdev, xfers, ARRAY_SIZE(xfers));

	if (ret < 0)