From mboxrd@z Thu Jan 1 00:00:00 1970 From: broonie@kernel.org (Mark Brown) Date: Fri, 17 Jun 2016 13:28:03 +0100 Subject: [PATCH 1/5] spi: do not fail if the CS line is not connected In-Reply-To: <20160617113622.GA10760@jack.zhora.eu> References: <1466150245-2648-1-git-send-email-andi.shyti@samsung.com> <1466150245-2648-2-git-send-email-andi.shyti@samsung.com> <20160617104725.GC26099@sirena.org.uk> <20160617113622.GA10760@jack.zhora.eu> Message-ID: <20160617122803.GN26099@sirena.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Jun 17, 2016 at 08:36:22PM +0900, Andi Shyti wrote: > > > In this case do not fail and defer to the SPI device drivers the > > > responsibility to check whether the num-cs is '0'. > > A SPI controller always has one chip seelct, it may not be controllable > > but it's at least logically present. > This is true, but there are cases where the CS is not connected > and this case needs to be treated separately to allow the device > to work. In what way? It is just as easy for a device with no physical chip select to have a logical chip select of 0 that it does nothing with as it is for that device to handle any other number. > This is the case of: > ./drivers/spi/spi-mpc52xx-psc.c:391: master->num_chipselect = 255; > ./drivers/spi/spi-oc-tiny.c:256: master->num_chipselect = 255; > ./drivers/spi/spi-pxa2xx-pci.c:64: .num_chipselect = -1, > ./drivers/spi/spi-bcm2835aux.c:436: master->num_chipselect = -1; These need fixing. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: not available URL: