diff options
| author | Pavan Holla <pholla@chromium.org> | 2024-04-09 01:58:57 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-09 17:38:29 +0200 |
| commit | c4ede56172dc5a9b60d7b7f11a5cf2073b14c14e (patch) | |
| tree | d5ad97724bbfcbfcc3aa33ce6797347a3f0513bb /drivers/usb/typec | |
| parent | 0fb782b5d5c462b2518b3b4fe7d652114c28d613 (diff) | |
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>
Diffstat (limited to 'drivers/usb/typec')
| -rw-r--r-- | drivers/usb/typec/ucsi/ucsi.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index 0e37404d309a..36e1b191f87d 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -1337,6 +1337,9 @@ static int ucsi_reset_ppm(struct ucsi *ucsi) goto out; } + /* Give the PPM time to process a reset before reading CCI */ + msleep(20); + ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci)); if (ret) goto out; @@ -1350,7 +1353,6 @@ static int ucsi_reset_ppm(struct ucsi *ucsi) goto out; } - msleep(20); } while (!(cci & UCSI_CCI_RESET_COMPLETE)); out: |