From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: mmc_spi.c driver Date: Tue, 15 Apr 2008 11:37:00 -0700 Message-ID: <200804151137.00997.david-b@pacbell.net> References: <1CF6EDDF0820924DA43C9A52FE7325950A27D544@MI8NYCMAIL17.Mi8.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Return-path: In-Reply-To: <1CF6EDDF0820924DA43C9A52FE7325950A27D544-3jZfQB9DylyX6QUl2nWcdlaTQe2KTcn/@public.gmane.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org On Thursday 03 April 2008, hartleys wrote: > Hello all, > > I'm trying to use the mmc_spi.c driver on an EP93xx platform and ran > into the "can't share SPI bus" issue. > > My platform currently has an EEPROM (SST25LF040A using the at25.c > driver) and a MMC socket connected to the SPI bus. Just to see what > would happen I commented out the return when multiple devices are found > and just let the driver load. The driver then appears to load ok and I > can mount the MMC card and still access the EEPROM. Presumably that means you're doing mutual exclusion "by hand" and accessing one device at a time. If you access both devices concurrently -- say, running a script that loops over EEPROM access in the background while runing an FSCK over MMC in the foreground -- I'd expect you to see problems caused by EEPROM operations appearing in the midst of multi-phase MMC operations. > Is there a patch to correctly handle the shared bus issue? Nothinge mergeable. > If not has anyone thought about what might need to be done? Yes; check the list archives. > Also, I have hooked up the card detect irq thru the > host->pdata->init(&spi->dev, mmc_spi_detect_irq, mmc) call and added a > comment in mmc_spi_detect_irq() to make sure it is called. Nothing > happens after that. I haven't looked into what mmc_detect_change() does > yet but shouldn't I see a new message from the mmc stuff about a "new > MMC card on SPI"? Are you actually getting the IRQ? However, card detection can be a bit troublesome for various reasons, and there's a known (but un-solved) issue whereby MMC-over-SPI really wants to start out with a card that's just been through a power cycle reset. - Dave > Maybe I'm just missing something... still pretty new at this whole Linux > thing... ;-) > > Thanks for the help, > Hartley Sweeten > > ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone