patch "iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels" added to staging-linus

This is a note to let you know that I've just added the patch titled

iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels

to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 9898cb24e454602beb6e17bacf9f97b26c85c955 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <[email protected]>
Date: Fri, 9 Jul 2021 12:11:10 +0200
Subject: iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels
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The ADS7950 requires that CS is deasserted after each SPI word. Before commit e2540da86ef8 ("iio: adc: ti-ads7950: use SPI_CS_WORD to reduce CPU usage") the driver used a message with one spi transfer per channel where each but the last one had .cs_change set to enforce a CS toggle. This was wrongly translated into a message with a single transfer and .cs_change set which results in a CS toggle after each word but the last which corrupts the first adc conversion of all readouts after the first readout.

---
 drivers/iio/adc/ti-ads7950.c | 1 -
 1 file changed, 1 deletion(-)

index 2383eacada87..a2b83f0bd526 100644
@@ -568,7 +568,6 @@ static int ti_ads7950_probe(struct spi_device *spi)
 	st->ring_xfer.tx_buf = &st->tx_buf[0];
 	st->ring_xfer.rx_buf = &st->rx_buf[0];
 	/* len will be set later */
-	st->ring_xfer.cs_change = true;
 
 	spi_message_add_tail(&st->ring_xfer, &st->ring_msg);
 

2.32.0