From mboxrd@z Thu Jan 1 00:00:00 1970 From: broonie@opensource.wolfsonmicro.com (Mark Brown) Date: Wed, 30 May 2012 18:08:38 +0100 Subject: [PATCH 2/2] MFD: mc13xxx workaround SPI hardware bug on i.Mx In-Reply-To: <1338282389-26177-3-git-send-email-philippe.retornaz@epfl.ch> References: <1338282389-26177-1-git-send-email-philippe.retornaz@epfl.ch> <1338282389-26177-2-git-send-email-philippe.retornaz@epfl.ch> <1338282389-26177-3-git-send-email-philippe.retornaz@epfl.ch> Message-ID: <20120530170837.GR9947@opensource.wolfsonmicro.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, May 29, 2012 at 11:06:29AM +0200, Philippe R?tornaz wrote: > The MC13xxx PMIC is mainly used on i.Mx SoC. On thoses SoC the SPI > hardware will deassert CS line as soon as the SPI FIFO is empty. > The MC13xxx hardware is very sensitive to CS line change as it > corrupts the transfert if CS is deasserted in the middle of a register > read or write. > It is not possible to use the CS line as a GPIO on some SoC, so we > need to workaround this by implementing a single SPI transfer to > access the PMIC. Reviwed-by: Mark Brown though it's really sad this can't be done in the SPI controller where the bug is. You should also set use_single_rw in the regmap_config, though this is less critical as currently the core won't automatically generate any bulk I/O. Obviously this will affect a much wider range of devices when used with i.MX. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: Digital signature URL: