[PATCH] usb: typec: tcpm: Use configured PD revision for negotiation

[PATCH] usb: typec: tcpm: Use configured PD revision for negotiation

[Cosmo Chou]

Initialize negotiated_rev and negotiated_rev_prime based on the port's
configured PD revision (rev_major) rather than always defaulting to
PD_MAX_REV. This ensures ports start PD communication using their
appropriate revision level.

This allows proper communication with devices that require specific
PD revision levels, especially for the hardware designed for PD 1.0
or 2.0 specifications.

Signed-off-by: Cosmo Chou <chou.cosmo@gmail.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index a99db4e025cd..5a58c21c4d14 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4782,8 +4782,13 @@ static void run_state_machine(struct tcpm_port *port)
 		typec_set_pwr_opmode(port->typec_port, opmode);
 		port->pwr_opmode = TYPEC_PWR_MODE_USB;
 		port->caps_count = 0;
-		port->negotiated_rev = PD_MAX_REV;
-		port->negotiated_rev_prime = PD_MAX_REV;
+		if (port->pd_rev.rev_major > 0 && port->pd_rev.rev_major <= PD_MAX_REV + 1) {
+			port->negotiated_rev = port->pd_rev.rev_major - 1;
+			port->negotiated_rev_prime = port->pd_rev.rev_major - 1;
+		} else {
+			port->negotiated_rev = PD_MAX_REV;
+			port->negotiated_rev_prime = PD_MAX_REV;
+		}
 		port->message_id = 0;
 		port->message_id_prime = 0;
 		port->rx_msgid = -1;
@@ -5048,8 +5053,13 @@ static void run_state_machine(struct tcpm_port *port)
 					      port->cc2 : port->cc1);
 		typec_set_pwr_opmode(port->typec_port, opmode);
 		port->pwr_opmode = TYPEC_PWR_MODE_USB;
-		port->negotiated_rev = PD_MAX_REV;
-		port->negotiated_rev_prime = PD_MAX_REV;
+		if (port->pd_rev.rev_major > 0 && port->pd_rev.rev_major <= PD_MAX_REV + 1) {
+			port->negotiated_rev = port->pd_rev.rev_major - 1;
+			port->negotiated_rev_prime = port->pd_rev.rev_major - 1;
+		} else {
+			port->negotiated_rev = PD_MAX_REV;
+			port->negotiated_rev_prime = PD_MAX_REV;
+		}
 		port->message_id = 0;
 		port->message_id_prime = 0;
 		port->rx_msgid = -1;
-- 
2.43.0

Re: [PATCH] usb: typec: tcpm: Use configured PD revision for negotiation

[Amit Sunil Dhamne]

Hi Cosmo,

Thanks for the patch!

On 5/8/25 10:47 AM, Cosmo Chou wrote:
> Initialize negotiated_rev and negotiated_rev_prime based on the port's
> configured PD revision (rev_major) rather than always defaulting to
> PD_MAX_REV. This ensures ports start PD communication using their
> appropriate revision level.
>
> This allows proper communication with devices that require specific
> PD revision levels, especially for the hardware designed for PD 1.0
I didn't know PD1.0 is still used.
> or 2.0 specifications.
>
> Signed-off-by: Cosmo Chou <chou.cosmo@gmail.com>
> ---
>   drivers/usb/typec/tcpm/tcpm.c | 18 ++++++++++++++----
>   1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index a99db4e025cd..5a58c21c4d14 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4782,8 +4782,13 @@ static void run_state_machine(struct tcpm_port *port)
>   		typec_set_pwr_opmode(port->typec_port, opmode);
>   		port->pwr_opmode = TYPEC_PWR_MODE_USB;
>   		port->caps_count = 0;
> -		port->negotiated_rev = PD_MAX_REV;
> -		port->negotiated_rev_prime = PD_MAX_REV;
> +		if (port->pd_rev.rev_major > 0 && port->pd_rev.rev_major <= PD_MAX_REV + 1) {

For better readability, I'd prefer you use macros for the numerical 
values and implement this logic as a switch case. This would make the 
value difference between PD specification revision in PD Message header 
vs PD max revision AMS transparent to the reader.

Thanks,

Amit

> +			port->negotiated_rev = port->pd_rev.rev_major - 1;
> +			port->negotiated_rev_prime = port->pd_rev.rev_major - 1;
> +		} else {
> +			port->negotiated_rev = PD_MAX_REV;
> +			port->negotiated_rev_prime = PD_MAX_REV;
> +		}
>   		port->message_id = 0;
>   		port->message_id_prime = 0;
>   		port->rx_msgid = -1;
> @@ -5048,8 +5053,13 @@ static void run_state_machine(struct tcpm_port *port)
>   					      port->cc2 : port->cc1);
>   		typec_set_pwr_opmode(port->typec_port, opmode);
>   		port->pwr_opmode = TYPEC_PWR_MODE_USB;
> -		port->negotiated_rev = PD_MAX_REV;
> -		port->negotiated_rev_prime = PD_MAX_REV;
> +		if (port->pd_rev.rev_major > 0 && port->pd_rev.rev_major <= PD_MAX_REV + 1) {
> +			port->negotiated_rev = port->pd_rev.rev_major - 1;
> +			port->negotiated_rev_prime = port->pd_rev.rev_major - 1;
> +		} else {
> +			port->negotiated_rev = PD_MAX_REV;
> +			port->negotiated_rev_prime = PD_MAX_REV;
> +		}
>   		port->message_id = 0;
>   		port->message_id_prime = 0;
>   		port->rx_msgid = -1;