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 07BABCDB474 for ; Mon, 16 Oct 2023 13:55:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233240AbjJPNz2 (ORCPT ); Mon, 16 Oct 2023 09:55:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232380AbjJPNzZ (ORCPT ); Mon, 16 Oct 2023 09:55:25 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC363EB; Mon, 16 Oct 2023 06:55:23 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51D34C433C7; Mon, 16 Oct 2023 13:55:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697464523; bh=0yiuMspPwLpIVtahu6CyE1/zM4ZcZrYi/mvg9LDr9ZU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=A+9vFEXwiNmSlKNIO/JIfd+flMeyXnMoUltYCdk0YKitkj3KZ5F8CSephZk8PlZtz UKCbGtdCwguKOHwH0nw6mmG0uKmhjiDQNy5I+9TJc92JRTHDn6f9ud9KCAoZa0u0FZ po+IfCUBm7z+BLgEXPoSg/xhk1RBJLZ/KZJQpKSbsQaG44yHuE0N3j9IottZd/svjN acfmmnEI/c2vu2W6TWuxG33o0E3W0VnDwxw8EndH5jYzxIA8ZLG+Qp4Bil6KBO7a18 Aryu9bzXCh0HD3Sn6y3ol7jYNMh4yuQdYg3o2SzmnGSSw2AIcT9YdJvCNIvLNonu+X 4dv5Wb2S/h+cA== Received: from johan by xi.lan with local (Exim 4.96) (envelope-from ) id 1qsO3x-0004Ff-2S; Mon, 16 Oct 2023 15:55:18 +0200 Date: Mon, 16 Oct 2023 15:55:17 +0200 From: Johan Hovold To: Wolfram Sang Cc: linux-renesas-soc@vger.kernel.org, Geert Uytterhoeven , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/3] gnss: ubx: add support for the reset gpio Message-ID: References: <20230921133202.5828-1-wsa+renesas@sang-engineering.com> <20230921133202.5828-4-wsa+renesas@sang-engineering.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230921133202.5828-4-wsa+renesas@sang-engineering.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 21, 2023 at 03:32:01PM +0200, Wolfram Sang wrote: > Tested with a Renesas KingFisher board. Because my GNSS device is hooked > up via UART and I2C simultaneously, I could verify functionality by > opening/closing the GNSS device using UART and see if the corresponding > I2C device was visible on the bus. Again, please try to make the commit message self-contained (e.g. without implicitly referring to Subject). Also say something about which u-blox module this is needed for since the modules I've seen do not have a reset line. > static int ubx_set_active(struct gnss_serial *gserial) > @@ -29,6 +31,8 @@ static int ubx_set_active(struct gnss_serial *gserial) > if (ret) > return ret; > > + gpiod_set_value_cansleep(data->reset_gpio, 0); > + > return 0; > } > > @@ -37,6 +41,8 @@ static int ubx_set_standby(struct gnss_serial *gserial) > struct ubx_data *data = gnss_serial_get_drvdata(gserial); > int ret; > > + gpiod_set_value_cansleep(data->reset_gpio, 1); > + > ret = regulator_disable(data->vcc); > if (ret) > return ret; > @@ -90,6 +96,13 @@ static int ubx_probe(struct serdev_device *serdev) > if (ret < 0 && ret != -ENODEV) > goto err_free_gserial; > > + /* Start with reset asserted */ > + data->reset_gpio = devm_gpiod_get_optional(&serdev->dev, "reset", GPIOD_OUT_HIGH); > + if (IS_ERR(data->reset_gpio)) { > + ret = PTR_ERR(data->reset_gpio); > + goto err_free_gserial; > + } So this means that the reset line will be asserted indefinitely in case the GNSS receiver is not used. Are you sure that's a good idea? I don't know yet which module this is for, or how this signal is supposed to be used, but the above makes this look more like an active-high (regulator) enable signal. Perhaps that's what it is or should be modelled as (i.e. as a fixed regulator). > + > ret = gnss_serial_register(gserial); > if (ret) > goto err_free_gserial; Johan