From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:18267 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932560AbaDILOg (ORCPT ); Wed, 9 Apr 2014 07:14:36 -0400 Message-id: <53452B97.8020700@samsung.com> Date: Wed, 09 Apr 2014 13:14:31 +0200 From: Tomasz Stanislawski MIME-version: 1.0 To: Rahul Sharma , Andrzej Hajda Cc: "devicetree@vger.kernel.org" , linux-samsung-soc , sunil joshi , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , Kishon Vijay Abraham I , Rob Herring , Kyungmin Park , Kukjin Kim , Grant Likely , Sylwester Nawrocki , Rahul Sharma , "linux-media@vger.kernel.org" Subject: Re: [PATCHv2 1/3] phy: Add exynos-simple-phy driver References: <1396967856-27470-1-git-send-email-t.stanislaws@samsung.com> <1396967856-27470-2-git-send-email-t.stanislaws@samsung.com> <534506B1.4040908@samsung.com> In-reply-to: Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hi Rahul, On 04/09/2014 11:12 AM, Rahul Sharma wrote: > Hi Tomasz, > > On 9 April 2014 14:07, Andrzej Hajda wrote: >> Hi Tomasz, >> >> On 04/08/2014 04:37 PM, Tomasz Stanislawski wrote: >>> Add exynos-simple-phy driver to support a single register >>> PHY interfaces present on Exynos4 SoC. >>> >>> Signed-off-by: Tomasz Stanislawski [snip] >>> + >>> + regs = devm_ioremap(dev, res->start, res->end - res->start); >>> + if (!regs) { >>> + dev_err(dev, "failed to ioremap registers\n"); >>> + return -EFAULT; >>> + } >> >> Why not devm_ioremap_resource? If not, resource_size function calculates >> length of resource correctly. >> >> Anyway I like the idea of implementing multiple phys in one driver. >> The only drawback I see is that some phys will be created even there are >> no consumers for them. To avoid such situation you can try to use >> lazy approach - create phy only if there is request for it, >> exynos_phy_xlate callback should allow this. >> >> Regards >> Andrzej >> > > Idea looks good. How about keeping compatible which is independent > of SoC, something like "samsung,exynos-simple-phy" and provide Reg > and Bit through phy provider node. This way we can avoid SoC specific > hardcoding in phy driver and don't need to look into dt bindings for > each new SoC. A very nice idea BUT there is a very strong pressure from DT guys to avoid adding any bit fields/offsets/masks in DT nodes. Hopefully, as long as driver name starts with "exynos-" prefix one can hide SoCs specific tricks deep inside driver code. The idea behind this driver was not to create a generic phy for 1-bit devices but rather to hide SoC-specific issues from client drivers like DRM-HDMI. > > We can use syscon interface to access PMU bits like USB phy. > PMU is already registered as system controller > Ok. I will try to use it in PATCHv3. > Regards, > Rahul Sharma. > Regards, Tomasz Stanislawski