From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 3/4] serial: bcm2835: add auxiliary uart1 to device tree of bcm2835 Date: Mon, 21 Sep 2015 19:42:25 -0700 Message-ID: <5600C011.8020402@wwwdotorg.org> References: <1441974053-2630-1-git-send-email-kernel@martin.sperl.org> <1441974053-2630-4-git-send-email-kernel@martin.sperl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1441974053-2630-4-git-send-email-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org Cc: Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King , Lee Jones , Greg Kroah-Hartman , Jiri Slaby , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-serial@vger.kernel.org On 09/11/2015 05:20 AM, kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org wrote: > From: Martin Sperl > > Add the auxiliary uart1 device to the device tree of the bcm2835 SOC. > diff --git a/arch/arm/boot/dts/bcm2835.dtsi b/arch/arm/boot/dts/bcm2835.dtsi > + uart1: uart@7e215040 { > + compatible = "ns16550"; compatible should always include a precise HW-specific value; something like brcm,bcm2835-aux-uart. That way, if we find some other issue that needs working around on this HW in the future, all DTs will already contain the compatible value that SW needs in order to trigger that workaround. That's a generally true statement; i.e. irrespective of anything else in this series. I don't believe "ns16550" should be in the compatible value for this device, since the device cannot be successfully driven by SW that only knows about a standard 16650 UART. SW must know about the different divider, and there is no possibility of SW knowing about that before this series. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Mon, 21 Sep 2015 19:42:25 -0700 Subject: [PATCH 3/4] serial: bcm2835: add auxiliary uart1 to device tree of bcm2835 In-Reply-To: <1441974053-2630-4-git-send-email-kernel@martin.sperl.org> References: <1441974053-2630-1-git-send-email-kernel@martin.sperl.org> <1441974053-2630-4-git-send-email-kernel@martin.sperl.org> Message-ID: <5600C011.8020402@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 09/11/2015 05:20 AM, kernel at martin.sperl.org wrote: > From: Martin Sperl > > Add the auxiliary uart1 device to the device tree of the bcm2835 SOC. > diff --git a/arch/arm/boot/dts/bcm2835.dtsi b/arch/arm/boot/dts/bcm2835.dtsi > + uart1: uart at 7e215040 { > + compatible = "ns16550"; compatible should always include a precise HW-specific value; something like brcm,bcm2835-aux-uart. That way, if we find some other issue that needs working around on this HW in the future, all DTs will already contain the compatible value that SW needs in order to trigger that workaround. That's a generally true statement; i.e. irrespective of anything else in this series. I don't believe "ns16550" should be in the compatible value for this device, since the device cannot be successfully driven by SW that only knows about a standard 16650 UART. SW must know about the different divider, and there is no possibility of SW knowing about that before this series.