Date:   Wed, 12 Jan 2022 13:05:37 +0200
From:   Heikki Krogerus <heikki.krogerus@linux.intel.com>
To:     Wayne Chang <waynec@nvidia.com>
Cc:     gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        linux-usb@vger.kernel.org, singhanc@nvidia.com,
        stable@vger.kernel.org
Subject: Re: [PATCH v5 1/1] ucsi_ccg: Check DEV_INT bit only when starting
 CCG4
Message-ID: <Yd62AVTwH2pGgk4y@kuha.fi.intel.com>
References: <20220112094143.628610-1-waynec@nvidia.com>
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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