Hi Fabio, Oleksij, On Wed, Aug 21, 2024 at 04:39:39PM +0200, Oleksij Rempel wrote: > Hi Fabio, Stefan, > > On Wed, Aug 21, 2024 at 08:01:20AM -0300, Fabio Estevam wrote: > > Hi Stefan, > > > > On Mon, Aug 19, 2024 at 4:20 AM Stefan Eichenberger <eichest@xxxxxxxxx> wrote: > > > > > > From: Stefan Eichenberger <stefan.eichenberger@xxxxxxxxxxx> > > > > > > According to the i.MX8M Mini reference manual chapter "16.1.4.2 > > > Generation of Start" it is only necessary to poll for bus busy and > > > arbitration lost in multi master mode. This helps to avoid rescheduling > > > while the i2c bus is busy and avoids SMBus devices to timeout. > > > > > > Signed-off-by: Stefan Eichenberger <stefan.eichenberger@xxxxxxxxxxx> > > > Reviewed-by: Frank Li <Frank.Li@xxxxxxx> > > > > This fixes a pca953x probe error on an imx8mp board running linux-stable 6.6: > > > > [ 1.893260] pca953x 2-0020: failed writing register > > [ 1.898258] pca953x 2-0020: probe with driver pca953x failed with error -11 > > > > Could you please add a Fixes tag and Cc stable so that this can reach > > the stable kernels? > > > > Tested-by: Fabio Estevam <festevam@xxxxxxx> Thanks a lot for testing. Are the other patches required as well or did only introducing the master mode flag solve the issue? > > > > Thanks a lot, > > It looks like with this patch, the I2SR_IAL interrupt is not cleared. > I would expect some kind of interrupt storm. Can you confirm it? This is a good question. i2c_imx_trx_complete was never called in the interrupt handler. So that would mean the storm would already be there before just for a shorter time. We only clear the IFF flag in the isr. > This causes a processor interrupt request (if the interrupt enable is > asserted [IIEN = 1]). The interrupt is set when one of the following > occurs: > - One byte transfer is completed (the interrupt is set at the falling > edge of the ninth clock). > - An address is received that matches its own specific address in > Slave Receive mode. > - Arbitration is lost. Unfortunately, I don't have a device that uses multi master mode and we would only see it on such a device. However, also from the reference manual: > IAL must be cleared by software by writing a "0" to it at the start of > the interrupt service routine So most likely it was wrong the whole the time we just didn't see it before, could that be? I think a fix would be relatively easy we have to clear it at the beginning of the isr but after we read the status. I could add this to the series if you agree. Regards, Stefan
