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dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SDEgIyBI/HjpiIokDSqYjeK6NYaDZW/SpQ63rDnZEIo=; b=f1jcy5njFg7NXA t+oEM4KUh+/EAvCJYyhuOuzJDyg0n9frbZMJIbpeXg/4iYDKHqCDaFpuS3yxf/nrH1acAwNbM8lrd o+KBRXF26RcGbgUSoMIyPMp5qrLZ3ClcJj95J6m4WElgJNN80lXmU9/6W2ASN2sztmqLBk/aZXQOY GcWPNzyvWgH1drGHM/txfnpvOa7o6rNrze/VzLznisaB2j8HEi/hoPPIvPRFaUgTCskS3FbQr/x5C 1mDOLFiwtLZiqBi//olWU+OiUIGLkTjhpNLPTvEYPcqsQyq3Ge9ToSRcx1WfoDQQvZtdqU0/pf2kJ mgvKXf389sUnmZo/2s7Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hIbTX-0003PL-2m; Mon, 22 Apr 2019 16:07:23 +0000 Received: from bhuna.collabora.co.uk ([46.235.227.227]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hIbTU-0003Oh-19 for linux-i3c@lists.infradead.org; Mon, 22 Apr 2019 16:07:21 +0000 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 6F132280AE6; Mon, 22 Apr 2019 17:07:18 +0100 (BST) Date: Mon, 22 Apr 2019 18:07:15 +0200 From: Boris Brezillon To: Vitor Soares Subject: Re: [PATCH 1/3] i3c: fix i2c and i3c scl rate by bus mode Message-ID: <20190422180715.40abe1b9@collabora.com> In-Reply-To: <13D59CF9CEBAF94592A12E8AE55501350A61B3B4@DE02WEMBXB.internal.synopsys.com> References: <05fdeea79db83970e9ecb0d7045b4dd98f206f06.1555350118.git.vitor.soares@synopsys.com> <20190416075041.22f8e849@collabora.com> <13D59CF9CEBAF94592A12E8AE55501350A61596D@DE02WEMBXB.internal.synopsys.com> <20190416165250.0606e5a2@collabora.com> <13D59CF9CEBAF94592A12E8AE55501350A61B3B4@DE02WEMBXB.internal.synopsys.com> Organization: Collabora X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190422_090720_338950_C99B1EB3 X-CRM114-Status: GOOD ( 16.65 ) X-BeenThere: linux-i3c@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux I3C List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linux-i3c@lists.infradead.org" , "joao.pinto@synopsys.com" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Boris Brezillon Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-i3c" Errors-To: linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org On Mon, 22 Apr 2019 15:54:33 +0000 Vitor Soares wrote: > > > > > > > > > { > > > > > i3cbus->mode = mode; > > > > > > > > > > - if (!i3cbus->scl_rate.i3c) > > > > > - i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE; > > > > > - > > > > > - if (!i3cbus->scl_rate.i2c) { > > > > > - if (i3cbus->mode == I3C_BUS_MODE_MIXED_SLOW) > > > > > - i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE; > > > > > - else > > > > > - i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_PLUS_SCL_RATE; > > > > > + switch (i3cbus->mode) { > > > > > + case I3C_BUS_MODE_PURE: > > > > > + if (!i3cbus->scl_rate.i3c) > > > > > + i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE; > > > > > + break; > > > > > + case I3C_BUS_MODE_MIXED_FAST: > > > > > + if (!i3cbus->scl_rate.i3c) > > > > > + i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE; > > > > > + if (!i3cbus->scl_rate.i2c) > > > > > + i3cbus->scl_rate.i2c = i2c_scl_rate; > > > > > + break; > > > > > + case I3C_BUS_MODE_MIXED_SLOW: > > > > > + if (!i3cbus->scl_rate.i2c) > > > > > + i3cbus->scl_rate.i2c = i2c_scl_rate; > > > > > + i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c; > > > > > > > > Maybe we should do > > > > > > > > if (!i3cbus->scl_rate.i3c || > > > > i3cbus->scl_rate.i3c > i3cbus->scl_rate.i2c) > > > > i3cbus->scl_rate.i3c = i3cbus->scl_rate.i2c; > > > > > > > > Just in case the I3C rate forced by the user is lower than the max I2C > > > > rate. > > > > > > That was something that I considered but TBH it isn't a real use case. > > > > Add a WARN_ON() to at least catch such inconsistencies. And maybe we > > should add a dev_warn() when the user-defined rates do not match > > the mode/LVR constraints. It's easy to do a mistake when writing a dts. > > I think the WARN_ON() is too evasive on the screen and won't provide the > information we want. > The dev_warn() should work perfectly here. > > if (i3cbus->scl_rate.i3c < i3cbus->scl_rate.i2c) > dev_warn(&i3cbus->cur_master->dev->dev, > "%s: i3c-scl-hz lower then i2c-scl-hz\n", __func__); Using dev_warn() sounds good, though I don't think you need the __func__ here. Also, please print the i2c/i3c rates in the message, and align the second line on the open parens. > if (i3cbus->scl_rate.i2c != I3C_BUS_I2C_FM_SCL_RATE || > i3cbus->scl_rate.i2c != I3C_BUS_I2C_FM_PLUS_SCL_RATE) > dev_warn(&i3cbus->cur_master->dev->dev, > "%s: i2c-scl-hz not defined according MIPI I3C spec\n", > __func__); Is that really a problem? Having an i2c rate that is less than FM speed sounds like a valid case to me. > > Maybe it make more sense to do this check on of_populate_i3c_bus(), what > do you think? > No, we really want to have this check here, because we might support other HW description formats at some point (board-files, ACPI, ...). _______________________________________________ linux-i3c mailing list linux-i3c@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-i3c