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iio: adc: ad7793: replace usleep_range() with fsleep()

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The AD7792/AD7793 datasheet (Rev. B, page 25, RESET section)
says: "When a reset is initiated, the user must allow a period
of 500 us before accessing any of the on-chip registers."

Use fsleep(500) instead of usleep_range(500, 2000). The 500 us
minimum stays the same; fsleep() picks the upper slack itself
(about +25% on a default config -- narrower than the original
2000 us).

Add a code comment with the datasheet reference so the "why"
of the wait is visible at the call site.

Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Stepan Ionichev 2026-05-11 10:30:43 +05:00 committed by Jonathan Cameron
parent 8e9c394520
commit a67d263922
1 changed files with 6 additions and 1 deletions
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7
drivers/iio/adc/ad7793.c
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@ -268,7 +268,12 @@ static int ad7793_setup(struct iio_dev *indio_dev,
ret = ad_sd_reset(&st->sd);
if (ret < 0)
goto out;
usleep_range(500, 2000); /* Wait for at least 500us */
/*
* Per AD7792/AD7793 datasheet (Rev. B, page 25, RESET section),
* allow 500 us after a reset before accessing on-chip registers.
*/
fsleep(500);
/* write/read test for device presence */
ret = ad_sd_read_reg(&st->sd, AD7793_REG_ID, 1, &id);