From mboxrd@z Thu Jan 1 00:00:00 1970 From: soren.brinkmann@xilinx.com (=?utf-8?B?U8O2cmVu?= Brinkmann) Date: Thu, 25 Aug 2016 08:29:44 -0700 Subject: [PATCH 1/2] sdhci-of-arasan: Add quirk and device tree parameter to fake CD bit In-Reply-To: References: <1472080984-17373-1-git-send-email-zach.brown@ni.com> <20160825151047.GO16583@xsjsorenbubuntu> Message-ID: <20160825152944.GP16583@xsjsorenbubuntu> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 2016-08-25 at 17:23:47 +0200, Lars-Peter Clausen wrote: > On 08/25/2016 05:10 PM, S?ren Brinkmann wrote: > > On Wed, 2016-08-24 at 18:23:03 -0500, Zach Brown wrote: > >> The sdhci controller on xilinx zynq devices will not function unless > >> the cd bit is provided. http://www.xilinx.com/support/answers/61064.html > >> In cases where it is impossible to provide the cd bit in hardware, > >> setting the controller to test mode and then setting inserted to true > >> will get the controller to function with out the cd bit. > >> > >> The device property "fake-cd" will let the arasan driver know it needs > >> to fake the cd bit for the controller inorder for the controller to > >> function with a SD card that does not provide the CD bit. > > > > I thought the CD is, if not pinned out, tied off to some valid logic > > level. Isn't it enough to specify cd-inverted if needed to make it work > > in those cases? > > It is always brought out to some pin, that is the problem on the Zynq. This > means you'd have to set at least one pin aside as dummy CD or WP pin. Which > is not always possible when you are tight on available pins. I have to admit that I haven't looked at Vivado for quite a while. Is it possible to select EMIO for those pins? If those are not routed anything they should be tied to some logic level, I believe. If they are always forced to be on a physical pin, do you let that pin just float? Otherwise, the logic level should also be defined, give and take a logic inversion. S?ren