Re: [PATCH v4 1/1] ucsi_ccg: Check DEV_INT bit only when starting CCG4

From: Heikki Krogerus
Date: Wed Jan 12 2022 - 02:50:54 EST


Hi,

On Wed, Jan 12, 2022 at 01:49:50PM +0800, Wayne Chang wrote:
> From: Sing-Han Chen <singhanc@xxxxxxxxxx>
>
> after driver sending the UCSI_START cmd, CCGx would
> clear Bit 0:Device Interrupt in the INTR_REG if CCGX
> reset successfully.
>
> however, there might be a chance that other bits in
> INTR_REG are not cleared due to internal data queued
> in PPM and cause the driver thinks CCGx reset failed.
>
> the commit checks bit 0 in INTR_REG and ignore other
> bits. ucsi driver would reset PPM later.
>
> Fixes: 247c554a14aa ("usb: typec: ucsi: add support for Cypress CCGx")

So... no need to take this to the stable kernel releases?

> Signed-off-by: Sing-Han Chen <singhanc@xxxxxxxxxx>
> Signed-off-by: Wayne Chang <waynec@xxxxxxxxxx>
> ---

What has changed since v3 (and v2) - there is no patch changelog here?

In case this is new to you, you list those changes under that '---'
line so they don't become part of the permanent changelog:

https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format

> 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));

thanks,

--
heikki