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 9C0D1C43334 for ; Thu, 14 Jul 2022 06:10:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231987AbiGNGKN (ORCPT ); Thu, 14 Jul 2022 02:10:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38032 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230061AbiGNGKM (ORCPT ); Thu, 14 Jul 2022 02:10:12 -0400 Received: from mx1.tq-group.com (mx1.tq-group.com [93.104.207.81]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F895111C; Wed, 13 Jul 2022 23:10:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1657779010; x=1689315010; h=subject:from:to:cc:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=P9AJNp2QXvwNyY5/+365FzUMEht6BcEtqcmTPZGX75E=; b=MTwLoL4TwIRGvIJDLUUKkJfkwIgI0qG4vvLHUS8jO7/86z7ZIJX2wK7G wWmOdmeQe7k5cc1fEHBqxNoJbG5TFIF9Uf3qH9QoidyYYPiTIgBsz8S93 hL1LqFYHk31jTz4S0l+booHoe+BatkxnD8yF8QkrzGxVce/qTU6HcOPDJ Ex8SdskYOZMh5nO8h5RdXroN3sXuoKeUcJ9diTKYUE/WNCqlwWBaVxhU0 W6J4YGNBNlwozWdX3yHT3dfwvDpI7PvLiOcg8vU9TEiXC9vdtYaQJcDXD NRAtj0HmiDnq86kgwPWl5C2jOPoKJrmX/ZIob7eoB6h6wqeaidQ7DjIxh Q==; X-IronPort-AV: E=Sophos;i="5.92,269,1650924000"; d="scan'208";a="25039871" Received: from unknown (HELO tq-pgp-pr1.tq-net.de) ([192.168.6.15]) by mx1-pgp.tq-group.com with ESMTP; 14 Jul 2022 08:10:08 +0200 Received: from mx1.tq-group.com ([192.168.6.7]) by tq-pgp-pr1.tq-net.de (PGP Universal service); Thu, 14 Jul 2022 08:10:08 +0200 X-PGP-Universal: processed; by tq-pgp-pr1.tq-net.de on Thu, 14 Jul 2022 08:10:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1657779008; x=1689315008; h=from:to:cc:date:message-id:in-reply-to:references: mime-version:content-transfer-encoding:subject; bh=P9AJNp2QXvwNyY5/+365FzUMEht6BcEtqcmTPZGX75E=; b=lROZQmjo8XZOrbYaoHX8nHiq56BD2mcvBLhtOHv4668cXe7akkj3OO6t 9UNi4qkZr+TRNzZloSH9Po0ejte7cs8nackFOthJfozZG5l80CgmQjPjQ QFGlNETMFGVNSdaco/dUAUrvTe1qBGs+gH3/cjBB03EICpgvpvxE0cRCm hbjHHuXyORE/u9mGDo6o+ttOqBgbHEeR5gAqKpqs/CX0v+wjmMyEhpQ/9 i4+vaatJnC/y7FejBz02UCT+X+Y2Ckbd9vJjjl6P8yfTyHz2OSAY/8nPR OPlvPSRqOlMzTPuuuKtcH799p68gIsDi1GGLH7iJ1hFgKuaRaqeIO7CES w==; X-IronPort-AV: E=Sophos;i="5.92,269,1650924000"; d="scan'208";a="25039870" Subject: Re: Re: [PATCH 2/3] usb: misc: onboard_usb_hub: Add reset-gpio support Received: from vtuxmail01.tq-net.de ([10.115.0.20]) by mx1.tq-group.com with ESMTP; 14 Jul 2022 08:10:07 +0200 Received: from steina-w.localnet (unknown [10.123.49.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by vtuxmail01.tq-net.de (Postfix) with ESMTPSA id 9B031280056; Thu, 14 Jul 2022 08:10:07 +0200 (CEST) From: Alexander Stein To: Matthias Kaehlcke Cc: Greg Kroah-Hartman , Rob Herring , Krzysztof Kozlowski , linux-usb@vger.kernel.org, devicetree@vger.kernel.org Date: Thu, 14 Jul 2022 08:10:05 +0200 Message-ID: <5584585.DvuYhMxLoT@steina-w> Organization: TQ-Systems GmbH In-Reply-To: References: <20220712150627.1444761-1-alexander.stein@ew.tq-group.com> <1902562.PYKUYFuaPT@steina-w> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Matthias, Am Mittwoch, 13. Juli 2022, 18:59:44 CEST schrieb Matthias Kaehlcke: > Hi Alexander, > > On Wed, Jul 13, 2022 at 08:46:56AM +0200, Alexander Stein wrote: > > Hi Matthias, > > > > Am Dienstag, 12. Juli 2022, 20:18:05 CEST schrieb Matthias Kaehlcke: > > > On Tue, Jul 12, 2022 at 05:06:26PM +0200, Alexander Stein wrote: > > > > Despite default reset upon probe, release reset line after powering up > > > > the hub and assert reset again before powering down. > > > > > > > > Signed-off-by: Alexander Stein > > > > --- > > > > My current DT node on my TQMa8MPxL looks like this > > > > ``` > > > > &usb_dwc3_1 { > > > > > > > > dr_mode = "host"; > > > > #address-cells = <1>; > > > > #size-cells = <0>; > > > > pinctrl-names = "default"; > > > > pinctrl-0 = <&pinctrl_usbhub>; > > > > status = "okay"; > > > > > > > > hub_2_0: hub@1 { > > > > > > > > compatible = "usb451,8142"; > > > > reg = <1>; > > > > peer-hub = <&hub_3_0>; > > > > reset-gpio = <&gpio1 11 GPIO_ACTIVE_LOW>; > > > > > > > > }; > > > > > > > > hub_3_0: hub@2 { > > > > > > > > compatible = "usb451,8140"; > > > > reg = <2>; > > > > peer-hub = <&hub_2_0>; > > > > reset-gpio = <&gpio1 11 GPIO_ACTIVE_LOW>; > > > > > > > > }; > > > > > > > > }; > > > > ``` > > > > which I don't like much for 2 reasons: > > > > * the pinctrl has to be put in a common top-node of USB hub node. The > > > > pinctrl> > > > > > > > > can not be requested twice. > > > > > > Agreed, that's not great. The pinctrl doesn't have to be necessarily in > > > the > > > USB controller node, it could also be in the static section of the > > > board, > > > but that isn't really much of an improvement :( Not sure there is much > > > to > > > do given that the USB devices also process the pinctrl info (besides the > > > onboard_hub platform device doing the same). > > > > I tend to keep the pinctrl property next to the ones actually using them. > > But in this case it's not possible unfortunately. > > > > > > * Apparently there is no conflict on the reset-gpio only because just > > > > one > > > > device> > > > > > > > > gets probed here: > > > > > $ ls /sys/bus/platform/drivers/onboard-usb-hub/ > > > > > 38200000.usb:hub@1 bind uevent unbind > > > > > > Right, the driver creates a single platform device for each physical > > > hub. > > > > Thanks for confirmation. > > > > > > But this seems better than to use a common fixed-regulator referenced > > > > by > > > > both hub nodes, which just is controlled by GPIO and does not supply > > > > any > > > > voltages. > > > > > > Agreed, if the GPIO controls a reset line it should be implemented as > > > such. > > > > > > > Note: It might also be necessary to add bindings to specify ramp up > > > > times > > > > and/or reset timeouts. > > > > > > The times are hub specific, not board specific, right? If that's the > > > case > > > then a binding shouldn't be needed, the timing can be derived from the > > > compatible string. > > > > Well, yes they are hub specific, but board design might influence them as > > well, as in increased ramp up delay. > > Isn't the ramp up delay something that should be configured on the regulator > side with 'regulator-ramp-delay'? Sure, if you have a regulators you can do that. But even for the reset GPIO lines an RC circuit can stretch the ramp up. AFAIK there is no way to handle this despite inserting a waiting time in driver code itself. For now this is good, but it might be necessary to accompany for that at some point. Regards, Alexander > > > > drivers/usb/misc/onboard_usb_hub.c | 18 ++++++++++++++++++ > > > > 1 file changed, 18 insertions(+) > > > > > > > > diff --git a/drivers/usb/misc/onboard_usb_hub.c > > > > b/drivers/usb/misc/onboard_usb_hub.c index 6b9b949d17d3..348fb5270266 > > > > 100644 > > > > --- a/drivers/usb/misc/onboard_usb_hub.c > > > > +++ b/drivers/usb/misc/onboard_usb_hub.c > > > > @@ -7,6 +7,7 @@ > > > > > > > > #include > > > > #include > > > > > > > > +#include > > > > > > > > #include > > > > #include > > > > #include > > > > > > > > @@ -38,6 +39,7 @@ struct usbdev_node { > > > > > > > > struct onboard_hub { > > > > > > > > struct regulator *vdd; > > > > struct device *dev; > > > > > > > > + struct gpio_desc *reset_gpio; > > > > > > > > bool always_powered_in_suspend; > > > > bool is_powered_on; > > > > bool going_away; > > > > > > > > @@ -56,6 +58,10 @@ static int onboard_hub_power_on(struct onboard_hub > > > > *hub) > > > > > > > > return err; > > > > > > > > } > > > > > > > > + /* Deassert reset */ > > > > > > The comment isn't really needed, it's clear from the context. > > > > Ok, removed. > > > > > > + usleep_range(3000, 3100); > > > > > > These shouldn't be hard coded. Instead you could add a model specific > > > struct 'hub_data' (or similar) and associate it with the compatible > > > string through onboard_hub_match.data > > > > Will do. > > > > > You could use fsleep() instead of usleep_range(). It does the _range > > > part > > > automatically (with a value of 2x). > > > > Nice idea. > > > > > > + gpiod_set_value_cansleep(hub->reset_gpio, 0); > > > > > > Since this includes delays maybe put the reset inside an 'if > > > (hub->reset_gpio)' block. Not super important for these short delays, > > > but > > > they might be longer for some hubs. > > > > gpiod_set_value_cansleep includes delays? Without gpio_desc it returns > > early on. Or do you mean the usleep_range before? > > Yes, I was referring to the usleep_range() before. > > > Actually in this case the 3ms is the minimum time from VDD stable to de- > > assertion of GRST. So even in case the GPIO is manged by hardware itself, > > software has to wait here before proceeding, IMHO. > > Agreed.