From mboxrd@z Thu Jan 1 00:00:00 1970 From: vaibhav.hiremath@linaro.org (Vaibhav Hiremath) Date: Mon, 13 Jul 2015 22:11:07 +0530 Subject: [PATCH-v3 07/11] i2c: pxa: enable/disable i2c module across msg xfer In-Reply-To: <20150710082419.GE1528@katana> References: <1436210695-19159-1-git-send-email-vaibhav.hiremath@linaro.org> <1436210695-19159-8-git-send-email-vaibhav.hiremath@linaro.org> <20150710082419.GE1528@katana> Message-ID: <55A3EA23.8070009@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 10 July 2015 01:54 PM, Wolfram Sang wrote: > On Tue, Jul 07, 2015 at 12:54:51AM +0530, Vaibhav Hiremath wrote: >> From: Yi Zhang >> >> Enable i2c module/unit before transmission and disable when it finishes. >> >> why? >> It's because the i2c bus may be distrubed if the slave device, >> typically a touch, powers on. >> >> As we do not want to break slave mode support, this patch introduces >> DT property to control disable of the I2C module after xfer in master mode >> of operation. >> >> i2c-disable-after-xfer : If set, driver will disable I2C module after msg xfer > > Hmm, I am not sure this property fits into the "describing hardware" > category. And we can't make the below behaviour default, because the > udelay(100) will cause quite some latency. > >> Sorry for delayed response, I thought I responded to this, but when I was preparing for V4, realized it that I did not :) Yes, I agree that, this doesn't look like HW description. But I could not find any other mechanism to handle this. And also during V1 discussion, I did not get any objection to this approach. Thanks, Vaibhav