usb: typec: ucsi: Wait 20ms before reading CCI after a reset
authorPavan Holla <pholla@chromium.org>
Tue, 9 Apr 2024 01:58:57 +0000 (01:58 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 9 Apr 2024 15:38:29 +0000 (17:38 +0200)
commitc4ede56172dc5a9b60d7b7f11a5cf2073b14c14e
treed5ad97724bbfcbfcc3aa33ce6797347a3f0513bb
parent0fb782b5d5c462b2518b3b4fe7d652114c28d613
usb: typec: ucsi: Wait 20ms before reading CCI after a reset

The PPM might take time to process a reset. Allow 20ms for the reset to
be processed before reading the CCI.

This should not slow down existing implementations because they would
not set any bits in the CCI after a reset, and would take a 20ms delay
to read the CCI anyway. This change makes the delay explicit, and
reduces a CCI read. Based on the spec, the PPM has 10ms to set busy, so,
20ms seems like a reasonable delay before we read the CCI.

Signed-off-by: Pavan Holla <pholla@chromium.org>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240409-ucsi-reset-delay-v3-1-8440710b012b@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/typec/ucsi/ucsi.c