Thread (18 messages) 18 messages, 4 authors, 2016-07-15

[PATCH 1/2] i2c: qup: Cleared the error bits in ISR

From: Abhishek Sahu <hidden>
Date: 2016-05-12 06:18:57
Also in: linux-arm-msm, linux-i2c, lkml

On Thu, May 12, 2016 at 12:13:47AM -0500, Andy Gross wrote:
On Wed, May 11, 2016 at 11:04:17PM +0530, Abhishek Sahu wrote:

<snip>
quoted
quoted
      In qup_i2c_xfer and qup_i2c_xfer_v2 state is set to RESET at the
end, when
      there is no error. So would it be fine if we do it there
unconditionally ?

Regards,
Sricharan
RESET the QUP state wouldn't create any issue in the case of multiple calls.
The existing code also RESET the QUP state for bus_err but it is not
clearing
status bits.
It'd be better to not reset the QUP inside the ISR at all.  I think the better
solution is making the reset occur in the xfer function.  So just clear the bits
like you should in the isr, and defer reset till later.
This is a HW workaround for QUP where we need to RESET the core in
ISR. When interrupt is level triggerd, more than one interrupt may
fire in error cases and QUP will generate these interrupts after
completion of current interrupt. Thus we reset the core immediately
in the ISR to ward off the next interrupt.

-- 
Abhishek Sahu
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