From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 08 Jun 2021 09:32:35 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1lqWDz-00010J-K7 for lore@lore.pengutronix.de; Tue, 08 Jun 2021 09:32:35 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lqWDy-0008W1-Kk for lore@pengutronix.de; Tue, 08 Jun 2021 09:32:35 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=fb6jaUYBVDYcNFJD3OL3CwhvpTFgmj2tUnFfYmU98Z8=; b=j+UrLZlkFCalB0sz56RRPhccj8 xV7JmUVPbpaKk8YC05k9ZN+rMKkiXdR0IwZF8OqvRcoLEFk+/ZWJE0uvr0cwESM/2dnQ+vWe3JC3A 0aVy+qW55t00i225J53iAtxL+MtN4s8jVyNvVNkClrfIAvmTL0PaT/cfSHs30Z7A141Lqx6/NCuLk Si3CFUfl5rb/8PIQrVd89RebmiAnlFHOl8uj5raEK0VsO4kd5NwRoefxlk5GVIXUI2MaeKzZ3NFmL sfSkohrUDgpz9AJmE1JDv38eqtIJRUmiTjY9UjMUCHUlthTGkD+/SmwshG7egkSGn5KwPjNNgulEI 1XBfB4ag==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqWCc-006rbH-E3; Tue, 08 Jun 2021 07:31:10 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqWCX-006rac-7P for barebox@lists.infradead.org; Tue, 08 Jun 2021 07:31:07 +0000 Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[IPv6:::1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1lqWCV-0008J0-O3; Tue, 08 Jun 2021 09:31:03 +0200 To: Sascha Hauer Cc: Barebox List References: <20210607141057.23255-1-s.hauer@pengutronix.de> <20210607222233.GB5267@pengutronix.de> From: Ahmad Fatoum Message-ID: <2166dc52-64da-14bb-987c-7000c31c6882@pengutronix.de> Date: Tue, 8 Jun 2021 09:31:03 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <20210607222233.GB5267@pengutronix.de> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210608_003105_310265_FEB7BAAB X-CRM114-Status: GOOD ( 31.38 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:e::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.6 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 1/2] net: designware: eqos: reset phy X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) Hello Sascha, On 08.06.21 00:22, Sascha Hauer wrote: > On Mon, Jun 07, 2021 at 05:59:02PM +0200, Ahmad Fatoum wrote: >> Hello Sascha, >> >> On 07.06.21 16:10, Sascha Hauer wrote: >>> The designware eqos DT binding has support for specifying reset GPIOs. >>> Add support for them. >>> >>> Signed-off-by: Sascha Hauer >>> --- >>> drivers/net/designware_eqos.c | 33 +++++++++++++++++++++++++++++++++ >>> drivers/of/of_gpio.c | 7 +++++++ >>> 2 files changed, 40 insertions(+) >>> >>> diff --git a/drivers/net/designware_eqos.c b/drivers/net/designware_eqos.c >>> index d2baaeaf63..0321024169 100644 >>> --- a/drivers/net/designware_eqos.c >>> +++ b/drivers/net/designware_eqos.c >>> @@ -8,9 +8,11 @@ >>> >>> #include >>> #include >>> +#include >>> #include >>> #include >>> #include >>> +#include >>> #include >>> #include >>> #include >>> @@ -189,6 +191,33 @@ struct eqos_desc { >>> >>> #define MII_BUSY (1 << 0) >>> >>> +static int eqos_phy_reset(struct device_d *dev, struct eqos *eqos) >>> +{ >>> + int phy_reset; >>> + int ret; >>> + u32 delays[3] = { 0, 0, 0 }; >>> + >>> + phy_reset = of_get_named_gpio(dev->device_node, "snps,reset-gpio", 0); >>> + >>> + if (!gpio_is_valid(phy_reset)) >>> + return 0; >> >> Whitespace is wrong. >> >>> + >>> + ret = gpio_request(phy_reset, "phy-reset"); >>> + if (ret) >>> + return ret; >> >> Can you use gpiod_get instead? This would reduce the boilerplate here. > > Sure. I didn't realize I don't honour the active high/low flags the way > I did it. > >> >>> + >>> + of_property_read_u32_array(dev->device_node, >>> + "snps,reset-delays-us", >>> + delays, ARRAY_SIZE(delays)); >>> + >> >> Looks strange to read out a delay and not act on it. I'd prefer >> waiting delays[0] here. > > Yes, it looks strange, but that's because the binding doesn't make much > sense. Why should I insert a delay before doing anything? .--------. POR --------->|R flip |---- Regulator ----> PHY VDD .->|S flop | | `--------' | | | RESET GPIO -----'`-------------------------------> PHY Reset (active low) It's stupid, but it works with Linux and wouldn't with barebox (if PHY VDD takes too long to stabilize)... ^^' > I can a delay here, it wouldn't make much difference as all users except > one specify zero delay here anyway. For the one exception I would bet > someone has inserted the first delay without a good reason, they are all > 10000. That's probably true. I still think mimicking Linux' interpretation of bindings is a good general rule to follow. >> >>> + gpio_direction_active(phy_reset, 0); >> >> This always sets logical zero, because gpio_request above doesn't >> accept a flag telling it otherwise. You'll need of_get_named_gpio_flags >> here, at which point, you'll have basically open-coded gpiod_get(), so >> you could use that. > > Right. > >> >>> + udelay(delays[1]); >> >> Linux rounds up to 1 msec granularity here. We should do likewise. > > I don't see a good reason for that. The Linux driver used udelay() > initially, that was changed to msleep as the times were too long for > busy waiting. I have no clue why the author didn't use usleep_range > instead. Same reason: Device trees are tested with Linux. They've a better chance of just working when we round up wait times the same way. > >> >>> + gpio_set_active(phy_reset, 1); >> >> Nitpick: true/false. > > Ok. > > Sascha > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox