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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=unavailable 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 87370C33CA4 for ; Sat, 11 Jan 2020 10:51:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D01A2087F for ; Sat, 11 Jan 2020 10:51:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578739862; bh=cTuWgKCN3FBK/E/Nnb+VWrwvbZTJ2ygu/AkLoz8trO0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=tpYsKdkJKafHJWPYa1H6EjM3o8NRRWI3oBL1JRQFJzekgdTRydb3/rojyHQL6zyy1 6BYqbpnt9cQsd6aIP3pV3Dezd/cebOXTQYehsNQ02g647dFUNyZpMNLg7EYL+gnCYp /DR5k1eT7ScdHeIcPnCalmPrtYfL3bXeB3XZhnmw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729007AbgAKKvB (ORCPT ); Sat, 11 Jan 2020 05:51:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:45188 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728974AbgAKKvB (ORCPT ); Sat, 11 Jan 2020 05:51:01 -0500 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 508E920848; Sat, 11 Jan 2020 10:50:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578739860; bh=cTuWgKCN3FBK/E/Nnb+VWrwvbZTJ2ygu/AkLoz8trO0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uyUYba7N1OZqK69x8xhFPT8qFwy2xCFwzShFbBJhd+Pmt8Sr4pmjv7UKqW7Tyq6JR 7au2OQM0TuxWoZVhR2B0X6EIieDCjJrbnYfYGvTg9Uh2wxp1bz6vGCkf3GAqX0oyKB qHrCFZfi/euO+G4vuZcfIT0jPFPmhp/hrBj4gmBQ= Date: Sat, 11 Jan 2020 10:50:55 +0000 From: Jonathan Cameron To: Andreas Klinger Cc: robh+dt@kernel.org, mark.rutland@arm.com, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, rpi-receiver@htl-steyr.ac.at, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] iio: srf04: add power management feature Message-ID: <20200111105055.42c814ca@archlinux> In-Reply-To: <20200109083926.GA5377@arbad> References: <20200109083926.GA5377@arbad> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, 9 Jan 2020 09:39:28 +0100 Andreas Klinger wrote: > Add suspend and resume operations for being used by optional power > management. > > The suspend function is switching off an GPIO which can be used by the > hardware to switch power off. The resume function is switching the GPIO > on and sleeps an adjustable time to give the device a chance to be up > and running. > > If activated the driver gets into autosuspend after some time of > inactivity. > Generally we try to avoid introducing ifdef CONFIG_PM where possible, because it tends to be error prone. Mostly marking functions __maybe_unused is sufficient. Otherwise looks good to me. Jonathan > Suggested-by: Franz Parzer > Signed-off-by: Andreas Klinger > --- > drivers/iio/proximity/srf04.c | 104 +++++++++++++++++++++++++++++++++- > 1 file changed, 103 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/proximity/srf04.c b/drivers/iio/proximity/srf04.c > index 01eb8cc63076..b19d910298d6 100644 > --- a/drivers/iio/proximity/srf04.c > +++ b/drivers/iio/proximity/srf04.c > @@ -45,6 +45,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -56,6 +57,7 @@ struct srf04_data { > struct device *dev; > struct gpio_desc *gpiod_trig; > struct gpio_desc *gpiod_echo; > + struct gpio_desc *gpiod_power; > struct mutex lock; > int irqnr; > ktime_t ts_rising; > @@ -63,6 +65,7 @@ struct srf04_data { > struct completion rising; > struct completion falling; > const struct srf04_cfg *cfg; > + int startup_time_ms; > }; > > static const struct srf04_cfg srf04_cfg = { > @@ -97,6 +100,9 @@ static int srf04_read(struct srf04_data *data) > u64 dt_ns; > u32 time_ns, distance_mm; > > + if (data->gpiod_power) > + pm_runtime_get_sync(data->dev); > + > /* > * just one read-echo-cycle can take place at a time > * ==> lock against concurrent reading calls > @@ -110,6 +116,11 @@ static int srf04_read(struct srf04_data *data) > udelay(data->cfg->trigger_pulse_us); > gpiod_set_value(data->gpiod_trig, 0); > > + if (data->gpiod_power) { > + pm_runtime_mark_last_busy(data->dev); > + pm_runtime_put_autosuspend(data->dev); > + } > + > /* it should not take more than 20 ms until echo is rising */ > ret = wait_for_completion_killable_timeout(&data->rising, HZ/50); > if (ret < 0) { > @@ -268,6 +279,26 @@ static int srf04_probe(struct platform_device *pdev) > return PTR_ERR(data->gpiod_echo); > } > > +#ifdef CONFIG_PM > + data->gpiod_power = devm_gpiod_get_optional(dev, "power", > + GPIOD_OUT_LOW); As the gpio is optional anyway and the various runtime pm calls will be stubbed out if CONFIG_PM is not enabled, it seems to me that we can just always leave this code in place. So drop the CONFIG_PM protection. > + if (IS_ERR(data->gpiod_power)) { > + dev_err(dev, "failed to get power-gpios: err=%ld\n", > + PTR_ERR(data->gpiod_power)); > + return PTR_ERR(data->gpiod_power); > + } > + if (data->gpiod_power) { > + > + if (of_property_read_u32(dev->of_node, "startup-time-ms", > + &data->startup_time_ms)) > + data->startup_time_ms = 100; > + dev_dbg(dev, "using power gpio: startup-time-ms=%d\n", > + data->startup_time_ms); > + } > +#else > + data->gpiod_power = NULL; > +#endif > + > if (gpiod_cansleep(data->gpiod_echo)) { > dev_err(data->dev, "cansleep-GPIOs not supported\n"); > return -ENODEV; > @@ -296,14 +327,85 @@ static int srf04_probe(struct platform_device *pdev) > indio_dev->channels = srf04_chan_spec; > indio_dev->num_channels = ARRAY_SIZE(srf04_chan_spec); > > - return devm_iio_device_register(dev, indio_dev); > + ret = iio_device_register(indio_dev); > + if (ret < 0) { > + dev_err(data->dev, "iio_device_register: %d\n", ret); > + return ret; > + } > + > + if (data->gpiod_power) { > + pm_runtime_set_autosuspend_delay(data->dev, 1000); > + pm_runtime_use_autosuspend(data->dev); > + > + ret = pm_runtime_set_active(data->dev); > + if (ret) { > + dev_err(data->dev, "pm_runtime_set_active: %d\n", ret); > + iio_device_unregister(indio_dev); > + } > + > + pm_runtime_enable(data->dev); > + pm_runtime_idle(data->dev); > + } > + > + return ret; > } > > +static int srf04_remove(struct platform_device *pdev) > +{ > + struct iio_dev *indio_dev = platform_get_drvdata(pdev); > + struct srf04_data *data = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + > + if (data->gpiod_power) { > + pm_runtime_disable(data->dev); > + pm_runtime_set_suspended(data->dev); > + } > + > + return 0; > +} > + > +#ifdef CONFIG_PM If we drop CONFIG_PM these will need to be marked __maybe_unused. > +static int srf04_pm_runtime_suspend(struct device *dev) > +{ > + struct platform_device *pdev = container_of(dev, > + struct platform_device, dev); > + struct iio_dev *indio_dev = platform_get_drvdata(pdev); > + struct srf04_data *data = iio_priv(indio_dev); > + > + gpiod_set_value(data->gpiod_power, 0); > + > + return 0; > +} > + > +static int srf04_pm_runtime_resume(struct device *dev) > +{ > + struct platform_device *pdev = container_of(dev, > + struct platform_device, dev); > + struct iio_dev *indio_dev = platform_get_drvdata(pdev); > + struct srf04_data *data = iio_priv(indio_dev); > + > + gpiod_set_value(data->gpiod_power, 1); > + msleep(data->startup_time_ms); > + > + return 0; > +} > + > +static const struct dev_pm_ops srf04_pm_ops = { > + SET_RUNTIME_PM_OPS(srf04_pm_runtime_suspend, > + srf04_pm_runtime_resume, NULL) > +}; > +#endif > + > static struct platform_driver srf04_driver = { > .probe = srf04_probe, > + .remove = srf04_remove, > .driver = { > .name = "srf04-gpio", > .of_match_table = of_srf04_match, > +#ifdef CONFIG_PM > + .pm = &srf04_pm_ops, > +#endif > }, > }; >