Hello Dan,
On Wed, May 08, 2024 at 10:53:05AM GMT, Dan Carpenter wrote:
> Hello Diogo Ivo,
>
> Commit 27ffe4ff0b33 ("usb: typec: ucsi: Only enable supported
> notifications") from Mar 27, 2024 (linux-next), leads to the
> following Smatch static checker warning:
>
> drivers/usb/typec/ucsi/ucsi.c:1671 ucsi_get_supported_notifications()
> warn: was expecting a 64 bit value instead of '((((1))) << (24))'
>
> drivers/usb/typec/ucsi/ucsi.c
> 1665 static u64 ucsi_get_supported_notifications(struct ucsi *ucsi)
> 1666 {
> 1667 u8 features = ucsi->cap.features;
> 1668 u64 ntfy = UCSI_ENABLE_NTFY_ALL;
> 1669
> 1670 if (!(features & UCSI_CAP_ALT_MODE_DETAILS))
> --> 1671 ntfy &= ~UCSI_ENABLE_NTFY_CAM_CHANGE;
>
> ntfy is a u64 but UCSI_ENABLE_NTFY_CAM_CHANGE is unsigned long. So on
> a 32 bit system this will clear the high 32 bits. So far as I can see
> ntfy should just be a u32. Either way, the types should match.
> BIT_ULL() is the way to do that if it really needs to be a u64.
In my view this variable really should be a u64 and the definitions of
the UCSI_ENABLE_NTFY_* need to be changed to BIT_ULL(). This is due to
UCSI versions 2.0 and up definining a new notification on bit 33, crossing
the u32 barrier. My suggestion for addressing this is sending two
patches, one for changing BIT() -> BIT_ULL() and adding the missing
define for the notification of bit 33 and a separate patch to handle
this new notification bit in ucsi_get_supported_notifications()/ucsi_init().
Thank you for the report and please let me know if this sounds
reasonable, or if it would be better to split the changes in another
way.
Best regards,
Diogo
