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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FB4BC433F5 for ; Sun, 2 Oct 2022 13:21:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229870AbiJBNVZ (ORCPT ); Sun, 2 Oct 2022 09:21:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229681AbiJBNVV (ORCPT ); Sun, 2 Oct 2022 09:21:21 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8AF24621B; Sun, 2 Oct 2022 06:21:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9E07CB80D31; Sun, 2 Oct 2022 13:21:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B486C433C1; Sun, 2 Oct 2022 13:21:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664716878; bh=KkBNlEX1wSNIgeTxdgBGFj0Kj0Q76m0kWPrOKhjgtLw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=f/tbLeQcCG1zEYWTRHBCZ/kwRtpnxyZpSNl+qm1RXzfmgGQlz8YguLUGGtu/ewA0l Aeft5p8hkKAhgmiR50/U0f8ckKTC62um2lG7b6XOM1uzLUpN0Nj0xyt7wE9kcH503S BX25TaCwVV8ukbxOhNb8jToPmxxlkqqgoz+6kSOPYKnJ+OM7nDgE9n2Wl4HAJnUxNP G2uSrfsMk5q75GSB3J9skFX1RsGgzGxctAGRkZaWI88zKSUQTWQXe4aFTMu7JzCPgy vu1Ch3/G/uErzOtQOLtmT9wlI/q5LmwjBmWpAew+BQzel+LXzTs6P4c3nBFvrZDZJL 9GzUkVElNPnkQ== Date: Sun, 2 Oct 2022 14:21:34 +0100 From: Jonathan Cameron To: Rajat Khandelwal Cc: lars@metafoo.de, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] iio: pressure: mpl115: Implementing low power mode by shutdown gpio Message-ID: <20221002142134.4d7c5fe9@jic23-huawei> In-Reply-To: <20220927174212.1776567-1-rajat.khandelwal@intel.com> References: <20220927174212.1776567-1-rajat.khandelwal@intel.com> X-Mailer: Claws Mail 4.1.0 (GTK 3.24.34; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Sep 2022 23:12:12 +0530 Rajat Khandelwal wrote: > 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 Ah. I missed there was a v2 and replied to v1. > --- > > 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);