From patchwork Tue Sep 27 17:42:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rajat Khandelwal X-Patchwork-Id: 12989202 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1F3CC32771 for ; Mon, 26 Sep 2022 18:02:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229890AbiIZSCB (ORCPT ); Mon, 26 Sep 2022 14:02:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229903AbiIZSBj (ORCPT ); Mon, 26 Sep 2022 14:01:39 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B0D625CD; Mon, 26 Sep 2022 10:42:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1664214156; x=1695750156; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=cG2DvqSDLyI1J+v9C/CXBPyOFA8Bzn/CTqdg+/ubto0=; b=jcLuSexnv1HK6URTVRO/UFQfnxcICphtiQZYCCgIlmIWVhMosPL9TC8Q 4CgrhYguKwR0XaQ/QFNrmW3XPqpBHMYRc52vkyIrQES4hPkKxYgzD/5Nt e0kH1X7Ymsvxe9copiD6JoPXry4+WDfD9TxhowUTkrYgoGElKAGAEeQJV nehO6GE8yT8vQ4aNimLxmv8O3V3cbZ0UGie2WqnPxR17JTNMxL4sWCohP 3QS6NC2puTKhtC3Tf4Iot6TDD8+MfyulTIh2YfQ6jVt4fluLRmwcwN4Ut y25PeeHlWVgHJYQ4TMGlu1u9zpWsISL7uluoO29AlmKaxnz1ClEEYqPkc Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10482"; a="302569735" X-IronPort-AV: E=Sophos;i="5.93,346,1654585200"; d="scan'208";a="302569735" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2022 10:42:35 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10482"; a="651920180" X-IronPort-AV: E=Sophos;i="5.93,346,1654585200"; d="scan'208";a="651920180" Received: from unknown (HELO rajath-NUC10i7FNH..) ([10.223.165.55]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2022 10:42:33 -0700 From: Rajat Khandelwal To: jic23@kernel.org, lars@metafoo.de Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Rajat Khandelwal Subject: [PATCH v2] iio: pressure: mpl115: Implementing low power mode by shutdown gpio Date: Tue, 27 Sep 2022 23:12:12 +0530 Message-Id: <20220927174212.1776567-1-rajat.khandelwal@intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org MPL115 supports shutdown gpio which can be used to set the default state to low power mode. Power from all internal circuits and registers is removed. This is done by pulling the SHDN pin to low. This patch sets the default mode to low-power and only exits when a reading is required from the chip. This maximises power savings. According to spec., a wakeup time period of ~5 ms exists between waking up and actually communicating with the device. This is implemented using sleep delay. Signed-off-by: Rajat Khandelwal --- v2: Grammatically completing subject line drivers/iio/pressure/mpl115.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-) diff --git a/drivers/iio/pressure/mpl115.c b/drivers/iio/pressure/mpl115.c index 5bf5b9abe6f1..c0ad3e941d05 100644 --- a/drivers/iio/pressure/mpl115.c +++ b/drivers/iio/pressure/mpl115.c @@ -3,13 +3,12 @@ * mpl115.c - Support for Freescale MPL115A pressure/temperature sensor * * Copyright (c) 2014 Peter Meerwald - * - * TODO: shutdown pin */ #include #include #include +#include #include "mpl115.h" @@ -27,6 +26,7 @@ struct mpl115_data { s16 a0; s16 b1, b2; s16 c12; + struct gpio_desc *shutdown; const struct mpl115_ops *ops; }; @@ -102,13 +102,27 @@ static int mpl115_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_PROCESSED: - ret = mpl115_comp_pressure(data, val, val2); + if (data->shutdown) { + gpiod_set_value(data->shutdown, 0); + usleep_range(5000, 6000); + ret = mpl115_comp_pressure(data, val, val2); + gpiod_set_value(data->shutdown, 1); + } else + ret = mpl115_comp_pressure(data, val, val2); + if (ret < 0) return ret; return IIO_VAL_INT_PLUS_MICRO; case IIO_CHAN_INFO_RAW: /* temperature -5.35 C / LSB, 472 LSB is 25 C */ - ret = mpl115_read_temp(data); + if (data->shutdown) { + gpiod_set_value(data->shutdown, 0); + usleep_range(5000, 6000); + ret = mpl115_read_temp(data); + gpiod_set_value(data->shutdown, 1); + } else + ret = mpl115_read_temp(data); + if (ret < 0) return ret; *val = ret >> 6; @@ -185,6 +199,17 @@ int mpl115_probe(struct device *dev, const char *name, return ret; data->c12 = ret; + data->shutdown = devm_gpiod_get_optional(dev, "shutdown", + GPIOD_OUT_HIGH); + if (IS_ERR(data->shutdown)) + return dev_err_probe(dev, PTR_ERR(data->shutdown), + "cannot get shutdown gpio\n"); + + if (data->shutdown) + dev_dbg(dev, "low-power mode enabled"); + else + dev_dbg(dev, "low-power mode disabled"); + return devm_iio_device_register(dev, indio_dev); } EXPORT_SYMBOL_NS_GPL(mpl115_probe, IIO_MPL115);