On 22.10.2019 10:59, Kamel Bouhara wrote: > On 21/10/2019 22:20, Wolfram Sang wrote: >> On Wed, Oct 02, 2019 at 04:46:56PM +0200, Kamel Bouhara wrote: >>> Implement i2c bus recovery when slaves devices might hold SDA low. >>> In this case re-assign SCL/SDA to gpios and issue 9 dummy clock pulses >>> until the slave release SDA. >>> >>> Signed-off-by: Kamel Bouhara <kamel.bouhara@xxxxxxxxxxx> >> >> Setting up the bus_recovery looks OK. However, I don't see any call to >> i2c_recover_bus(), so the bus_recovery is never used. Did you test this >> and see an effect? >> > Indeed, I guess I mess it up while doing some git stuff, it should be > called from at91_do_twi_transfer() when the transfer times out... > I actually tested it and verified the recovery is triggered by pulling > the SCL to the ground ... > >> Also, I think we should merge this patch "[PATCH v3] i2c: at91: Send bus >> clear command if SCL or SDA is down" into this series. The crucial thing >> for both is when to apply the recovery (at the beginning of a >> transfer!). The rest is "just" that some HW needs a bus_recovery_info >> for pinctrl/GPIO handling (from this patch), while other HW needs a >> bus_recovery_info with a custom recover_bus callback. >> >> Opinions? >> > I'm OK to merge the two series. So at the beginning of a new transfer, we should check if SDA (or SCL?) is low and, if it's true, only then we should try recover the bus. Kamel, let me know if I can help with anything. Best regards, Codrin
