From mboxrd@z Thu Jan 1 00:00:00 1970 From: madhu.cr@ti.com (Madhusudhan) Date: Tue, 6 Jul 2010 10:34:09 -0500 Subject: [PATCH 05/15] omap: hsmmc: add virtual card detect support In-Reply-To: References: <1278376666-3509-1-git-send-email-ohad@wizery.com> <1278376666-3509-6-git-send-email-ohad@wizery.com> Message-ID: <822D79B5C25543B1A6F148B39E061459@am.dhcp.ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > -----Original Message----- > From: Ohad Ben-Cohen [mailto:ohad at wizery.com] > Sent: Tuesday, July 06, 2010 6:48 AM > To: Nicolas Pitre > Cc: linux-wireless at vger.kernel.org; linux-mmc at vger.kernel.org; linux- > omap at vger.kernel.org; linux-arm-kernel at lists.infradead.org; > linux at arm.linux.org.uk; Chikkature Rajashekar Madhusudhan; Luciano Coelho; > Andrew Morton; San Mehat; Pandita, Vikram > Subject: Re: [PATCH 05/15] omap: hsmmc: add virtual card detect support > > On Tue, Jul 6, 2010 at 1:22 PM, Ohad Ben-Cohen wrote: > > Note: the wl1271 device does support standard card detection, but > > AFAIK there's a limitation to use that with the specific omap > > controller the device is hardwired to. I will try to get more info > > about that, but probably Madhu can comment on that better. > > > Some correction and additional info: > > The wl1271 device has an issue which makes the standard card detect > mechanism irrelevant: it is always up, even if the power enable gpio > input of the device is down (the power enable input does not supply > the power to the chip, it's just logical digital high/low input upon > which the device reacts). That's why we must use software control for > emulating card detect with that device. > > In addition, as far as I could find out, the card detect mechanism on > the ZOOM is implemented by mechanical means, and thus is not relevant > for hardwired embedded SDIO devices (I'm not even sure card detect is > supported for the 3rd mmc controller). The card detect is supported through T2 GPIO interrupts only for MMC1 and MMC2. Such a mechanism is not present for MMC3 to which the WLAN chip is hardwired. Regards, Madhu