Re: [PATCH 4/5] usb: typec: fusb302: Tell SOP' messages apart from SOP

[Sebastian Reichel]

Hi,

On Tue, Nov 03, 2026 at 03:21:25PM +0400, Alexey Charkov wrote:
> The driver sends every message with the SOP ordered set and reports
> every received one as SOP, which leaves TCPM no way to reach the cable
> plug. Start a message with the SOP' ordered set when TCPM asks for it,
> and report a received message as SOP' when its RX FIFO token says so.
> 
> SOP' is Sync-1, Sync-1, Sync-3, Sync-3 in USB PD. The Sync-3 TX token
> and the RX FIFO token codes are from the token tables of the FUSB302B
> datasheet.
> 
> Nothing changes yet: TCPM asks for SOP' only from a port that claims
> cable communication, and the chip drops SOP' packets until ENSOP1 is
> set.
> 
> Signed-off-by: Alexey Charkov <alchark@xxxxxxxxxxx>
> ---

Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>

Greetings,

-- Sebastian

>  drivers/usb/typec/tcpm/fusb302.c     | 26 ++++++++++++++++++++------
>  drivers/usb/typec/tcpm/fusb302_reg.h | 10 ++++++++++
>  2 files changed, 30 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 3319f6a2b0c9..8b3a2e095ef8 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -961,7 +961,20 @@ static int tcpm_start_toggling(struct tcpc_dev *dev,
>  	return ret;
>  }
>  
> +/* K-codes of the ordered set that starts each kind of packet */
> +static const u8 fusb302_sop_tokens[][4] = {
> +	[TCPC_TX_SOP] = {
> +		FUSB302_TKN_SYNC1, FUSB302_TKN_SYNC1,
> +		FUSB302_TKN_SYNC1, FUSB302_TKN_SYNC2,
> +	},
> +	[TCPC_TX_SOP_PRIME] = {
> +		FUSB302_TKN_SYNC1, FUSB302_TKN_SYNC1,
> +		FUSB302_TKN_SYNC3, FUSB302_TKN_SYNC3,
> +	},
> +};
> +
>  static int fusb302_pd_send_message(struct fusb302_chip *chip,
> +				   enum tcpm_transmit_type type,
>  				   const struct pd_message *msg)
>  {
>  	int ret = 0;
> @@ -969,11 +982,9 @@ static int fusb302_pd_send_message(struct fusb302_chip *chip,
>  	u8 pos = 0;
>  	int len;
>  
> -	/* SOP tokens */
> -	buf[pos++] = FUSB302_TKN_SYNC1;
> -	buf[pos++] = FUSB302_TKN_SYNC1;
> -	buf[pos++] = FUSB302_TKN_SYNC1;
> -	buf[pos++] = FUSB302_TKN_SYNC2;
> +	memcpy(&buf[pos], fusb302_sop_tokens[type],
> +	       sizeof(fusb302_sop_tokens[type]));
> +	pos += sizeof(fusb302_sop_tokens[type]);
>  
>  	len = pd_header_cnt_le(msg->header) * 4;
>  	/* plug 2 for header */
> @@ -1037,6 +1048,7 @@ static int tcpm_pd_transmit(struct tcpc_dev *dev, enum tcpm_transmit_type type,
>  	mutex_lock(&chip->lock);
>  	switch (type) {
>  	case TCPC_TX_SOP:
> +	case TCPC_TX_SOP_PRIME:
>  		/* nRetryCount 3 in P2.0 spec, whereas 2 in PD3.0 spec */
>  		ret = fusb302_enable_tx_auto_retries(chip, negotiated_rev > PD_REV20 ?
>  						     FUSB_REG_CONTROL3_N_RETRIES_2 :
> @@ -1044,7 +1056,7 @@ static int tcpm_pd_transmit(struct tcpc_dev *dev, enum tcpm_transmit_type type,
>  		if (ret < 0)
>  			fusb302_log(chip, "Cannot update retry count ret=%d", ret);
>  
> -		ret = fusb302_pd_send_message(chip, msg);
> +		ret = fusb302_pd_send_message(chip, type, msg);
>  		if (ret < 0)
>  			fusb302_log(chip,
>  				    "cannot send PD message, ret=%d", ret);
> @@ -1475,6 +1487,8 @@ static int fusb302_pd_read_message(struct fusb302_chip *chip,
>  	 */
>  	if ((!len) && (pd_header_type_le(msg->header) == PD_CTRL_GOOD_CRC))
>  		tcpm_pd_transmit_complete(chip->tcpm_port, TCPC_TX_SUCCESS);
> +	else if ((token & FUSB302_RX_TKN_MASK) == FUSB302_RX_TKN_SOP1)
> +		tcpm_pd_receive(chip->tcpm_port, msg, TCPC_TX_SOP_PRIME);
>  	else
>  		tcpm_pd_receive(chip->tcpm_port, msg, TCPC_TX_SOP);
>  
> diff --git a/drivers/usb/typec/tcpm/fusb302_reg.h b/drivers/usb/typec/tcpm/fusb302_reg.h
> index edc0e4b0f1e6..c98a502bfbfc 100644
> --- a/drivers/usb/typec/tcpm/fusb302_reg.h
> +++ b/drivers/usb/typec/tcpm/fusb302_reg.h
> @@ -174,4 +174,14 @@ enum fusb302_txfifo_tokens {
>  	FUSB302_TKN_TXOFF = 0xFE,
>  };
>  
> +/* Tokens starting each packet in the FUSB302 RX FIFO, valid under the mask */
> +#define FUSB302_RX_TKN_MASK			GENMASK(7, 5)
> +enum fusb302_rxfifo_tokens {
> +	FUSB302_RX_TKN_SOP2DB = 0x60,
> +	FUSB302_RX_TKN_SOP1DB = 0x80,
> +	FUSB302_RX_TKN_SOP2 = 0xA0,
> +	FUSB302_RX_TKN_SOP1 = 0xC0,
> +	FUSB302_RX_TKN_SOP = 0xE0,
> +};
> +
>  #endif
> 
> -- 
> 2.56.0
>

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