From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7525AC4338F for ; Tue, 10 Aug 2021 06:55:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5920F61075 for ; Tue, 10 Aug 2021 06:55:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235109AbhHJG4E (ORCPT ); Tue, 10 Aug 2021 02:56:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:44780 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231482AbhHJG4D (ORCPT ); Tue, 10 Aug 2021 02:56:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1CC7660FC4; Tue, 10 Aug 2021 06:55:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1628578541; bh=SeHYDimNQH4mQD9jBWtANp0yyLGtmvplf8V0qnfkm7c=; h=Subject:To:From:Date:From; b=gpZKRx1t7tQqOGqwVMzJGF+Jej34LVKqjeye2P9wER19MOO082Lq8qOTD+oBD7sKJ liaeFRG1Tjr2F3hrvVl6mczePGYlef25Ho+psKRaeuemGM4BoKBisVBxjKs9+e/1jc L84QIZe7RgKkhJeutZKW4c+U+jjTJUT4jrlmZ6so= Subject: patch "iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels" added to staging-linus To: u.kleine-koenig@pengutronix.de, Jonathan.Cameron@huawei.com, Stable@vger.kernel.org, david@lechnology.com From: Date: Tue, 10 Aug 2021 08:55:31 +0200 Message-ID: <162857853155166@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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?= Date: Fri, 9 Jul 2021 12:11:10 +0200 Subject: iio: adc: ti-ads7950: Ensure CS is deasserted after reading channels MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Fixes: e2540da86ef8 ("iio: adc: ti-ads7950: use SPI_CS_WORD to reduce CPU usage") Signed-off-by: Uwe Kleine-König Reviewed-by: David Lechner Tested-by: David Lechner Cc: Link: https://lore.kernel.org/r/20210709101110.1814294-1-u.kleine-koenig@pengutronix.de Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ti-ads7950.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c index 2383eacada87..a2b83f0bd526 100644 --- a/drivers/iio/adc/ti-ads7950.c +++ b/drivers/iio/adc/ti-ads7950.c @@ -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