tree eb590e70104264325caebb6627cd8626150eca1b
parent 3b2571b8e8064a73eca2cec23cf86cfe7f7050f5
author Sven Peter <sven@svenpeter.dev> 1669842674 +0100
committer Hector Martin <marcan@marcan.st> 1695214323 +0900

usb: typec: tipd: Clear interrupts first

Right now the interrupt handler first reads all updated status registers
and only then clears the interrupts. It's possible that a duplicate
interrupt for a changed register or plug state comes in after the
interrupts have been processed but before they have been cleared:

* plug is inserted, TPS_REG_INT_PLUG_EVENT is set
* TPS_REG_INT_EVENT1 is read
* tps6598x_handle_plug_event() has run and registered the plug
* plug is removed again, TPS_REG_INT_PLUG_EVENT is set (again)
* TPS_REG_INT_CLEAR1 is written, TPS_REG_INT_PLUG_EVENT is cleared

We then have no plug connected and no pending interrupt but the tipd
core still thinks there is a plug. It's possible to trigger this with
e.g. a slightly broken Type-C to USB A converter.

Fix this by first clearing the interrupts and only then reading the
updated registers.

Fixes: 45188f27b3d0 ("usb: typec: tipd: Add support for Apple CD321X")
Fixes: 0a4c005bd171 ("usb: typec: driver for TI TPS6598x USB Power Delivery controllers")
Cc: stable <stable@kernel.org>
Signed-off-by: Sven Peter <sven@svenpeter.dev>