From patchwork Tue Sep 21 11:54:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 12507761 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 76239C433FE for ; Tue, 21 Sep 2021 11:54:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6100061178 for ; Tue, 21 Sep 2021 11:54:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232738AbhIULz4 (ORCPT ); Tue, 21 Sep 2021 07:55:56 -0400 Received: from relay10.mail.gandi.net ([217.70.178.230]:53535 "EHLO relay10.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232633AbhIULzs (ORCPT ); Tue, 21 Sep 2021 07:55:48 -0400 Received: (Authenticated sender: miquel.raynal@bootlin.com) by relay10.mail.gandi.net (Postfix) with ESMTPSA id E111D24001A; Tue, 21 Sep 2021 11:54:18 +0000 (UTC) From: Miquel Raynal To: Jonathan Cameron , Lars-Peter Clausen , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Thomas Petazzoni , Nuno Sa , Miquel Raynal Subject: [PATCH v4 12/16] iio: adc: max1027: Introduce an end of conversion helper Date: Tue, 21 Sep 2021 13:54:04 +0200 Message-Id: <20210921115408.66711-13-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210921115408.66711-1-miquel.raynal@bootlin.com> References: <20210921115408.66711-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org For now this helper only waits for the maximum duration of a single conversion. In practice, a "temperature measurement" will take twice this time because it will also carry another analog conversion but as here we will only care about the temperature conversion which happens first, we can still only wait for a single sample and get the right data. This helper will soon be improved to properly handle the end of conversion interrupt as well as a higher number of samples. Signed-off-by: Miquel Raynal --- drivers/iio/adc/max1027.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c index a044f4b598e0..e0175448c899 100644 --- a/drivers/iio/adc/max1027.c +++ b/drivers/iio/adc/max1027.c @@ -60,6 +60,9 @@ #define MAX1027_NAVG_32 (0x03 << 2) #define MAX1027_AVG_EN BIT(4) +/* Device can achieve 300ksps so we assume a 3.33us conversion delay */ +#define MAX1027_CONVERSION_UDELAY 4 + enum max1027_id { max1027, max1029, @@ -271,6 +274,15 @@ struct max1027_state { u8 reg ____cacheline_aligned; }; +static int max1027_wait_eoc(struct iio_dev *indio_dev) +{ + unsigned int conversion_time = MAX1027_CONVERSION_UDELAY; + + usleep_range(conversion_time, conversion_time * 2); + + return 0; +} + /* Scan from chan 0 to the highest requested channel. Include temperature on demand. */ static int max1027_configure_chans_and_start(struct iio_dev *indio_dev) { @@ -330,9 +342,11 @@ static int max1027_read_single_value(struct iio_dev *indio_dev, /* * For an unknown reason, when we use the mode "10" (write * conversion register), the interrupt doesn't occur every time. - * So we just wait 1 ms. + * So we just wait the maximum conversion time and deliver the value. */ - mdelay(1); + ret = max1027_wait_eoc(indio_dev); + if (ret) + return ret; /* Read result */ ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);