From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: Re: [PATCH 2/3] tty/serial: of_serial: add support for PXA/MMP uarts Date: Wed, 28 Jan 2015 12:06:09 -0500 Message-ID: <54C91701.2090006@hurleysoftware.com> References: <1422334209-23125-1-git-send-email-robh@kernel.org> <1422334209-23125-2-git-send-email-robh@kernel.org> <54C78823.7050504@hurleysoftware.com> <54C7AA2D.7080202@hurleysoftware.com> <54C7EA6A.4010805@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Rob Herring Cc: Greg Kroah-Hartman , Jiri Slaby , "linux-arm-kernel@lists.infradead.org" , "linux-serial@vger.kernel.org" List-Id: linux-serial@vger.kernel.org On 01/28/2015 09:21 AM, Rob Herring wrote: > On Tue, Jan 27, 2015 at 1:43 PM, Peter Hurley wrote: >> On 01/27/2015 11:44 AM, Rob Herring wrote: >>> On Tue, Jan 27, 2015 at 9:09 AM, Peter Hurley wrote: >>>> On 01/27/2015 09:30 AM, Rob Herring wrote: >>>>> On Tue, Jan 27, 2015 at 6:44 AM, Peter Hurley wrote: >>>>>> On 01/26/2015 11:50 PM, Rob Herring wrote: [...] >> OTOH, I didn't realize that patch removed the PXA driver. That driver has >> errata workarounds which didn't get integrated into the 8250 core; it seems >> a shame to toss that away. > > There was some discussion on errata in the prior versions. One of them > was deemed not needed. Another one is needed, but that's on certain > PXA2xx. So we'll need to pickup that work-around at some point, but it > is not yet needed here because PXA2xx is not enabled for DT. Do you know offhand which errata? If not, nbd; I can do a little digging. >> [ Sidebar: I did a trial split of 8250_core into a separate 8250 base module >> and an 8250 universal driver. I keep having to rework the split but it's >> pretty close now; the 8250 base module might be just the thing for simplifying >> the pxa driver and getting console/earlycon/dma for free. >> >> Let me see what I can do about getting that done. >> ] > > Yes, it would be nice to split the legacy ISA parts from the proper > platform driver. There's way too many kconfig options for the 8250 as > well IMO. After I finish the split, I can look at making most/all of those options dependent on the universal 8250 driver only. > BTW, It appears that the main motivator for a separate driver was to > add DMA support and that's what the out of tree driver adds. But now, > we would never add the PXA DMA API support and the 8250 driver has > learned DMA support. Yeah, PXA should not have been forked. But I say that with the benefit of hindsight. Regards, Peter Hurley