[PATCH v5 1/1] ucsi_ccg: Check DEV_INT bit only when starting CCG4

[PATCH v5 1/1] ucsi_ccg: Check DEV_INT bit only when starting CCG4

[Wayne Chang]

From: Sing-Han Chen <singhanc@nvidia.com>

CCGx clears Bit 0:Device Interrupt in the INTR_REG
if CCGx is reset successfully. However, there might
be a chance that other bits in INTR_REG are not
cleared due to internal data queued in PPM. This case
misleads the driver that CCGx reset failed.

The commit checks bit 0 in INTR_REG and ignores other
bits. The ucsi driver would reset PPM later.

Fixes: 247c554a14aa ("usb: typec: ucsi: add support for Cypress CCGx")
Cc: stable@vger.kernel.org
Signed-off-by: Sing-Han Chen <singhanc@nvidia.com>
Signed-off-by: Wayne Chang <waynec@nvidia.com>
---
V4 -> V5: Added Cc tag and revised the commit messages
V3 -> V4: Updated the Fixes tag
V2 -> V3: Added the Fixes tag
V1 -> V2: Fixed the name of Sign-off-by
 drivers/usb/typec/ucsi/ucsi_ccg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c
index bff96d64dddf..6db7c8ddd51c 100644
--- a/drivers/usb/typec/ucsi/ucsi_ccg.c
+++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
@@ -325,7 +325,7 @@ static int ucsi_ccg_init(struct ucsi_ccg *uc)
 		if (status < 0)
 			return status;
 
-		if (!data)
+		if (!(data & DEV_INT))
 			return 0;
 
 		status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
-- 
2.25.1

Re: [PATCH v5 1/1] ucsi_ccg: Check DEV_INT bit only when starting CCG4

[Heikki Krogerus]

On Wed, Jan 12, 2022 at 05:41:43PM +0800, Wayne Chang wrote:
> From: Sing-Han Chen <singhanc@nvidia.com>
> 
> CCGx clears Bit 0:Device Interrupt in the INTR_REG
> if CCGx is reset successfully. However, there might
> be a chance that other bits in INTR_REG are not
> cleared due to internal data queued in PPM. This case
> misleads the driver that CCGx reset failed.
> 
> The commit checks bit 0 in INTR_REG and ignores other
> bits. The ucsi driver would reset PPM later.
> 
> Fixes: 247c554a14aa ("usb: typec: ucsi: add support for Cypress CCGx")
> Cc: stable@vger.kernel.org
> Signed-off-by: Sing-Han Chen <singhanc@nvidia.com>
> Signed-off-by: Wayne Chang <waynec@nvidia.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> V4 -> V5: Added Cc tag and revised the commit messages
> V3 -> V4: Updated the Fixes tag
> V2 -> V3: Added the Fixes tag
> V1 -> V2: Fixed the name of Sign-off-by
>  drivers/usb/typec/ucsi/ucsi_ccg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c
> index bff96d64dddf..6db7c8ddd51c 100644
> --- a/drivers/usb/typec/ucsi/ucsi_ccg.c
> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> @@ -325,7 +325,7 @@ static int ucsi_ccg_init(struct ucsi_ccg *uc)
>  		if (status < 0)
>  			return status;
>  
> -		if (!data)
> +		if (!(data & DEV_INT))
>  			return 0;
>  
>  		status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
> -- 
> 2.25.1

thanks,

-- 
heikki