linux-kernel - Re: [PATCH v4 3/4] usb: typec: ucsi: Register SOP/SOP' Discover Identity Responses

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Message-ID: <Zedqb6_fe0GoUR9U@chromium.org>
Date: Tue, 5 Mar 2024 18:54:39 +0000
From: Prashant Malani <pmalani@...omium.org>
To: Jameson Thies <jthies@...gle.com>
Cc: heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org,
	bleung@...gle.com, abhishekpandit@...omium.org,
	andersson@...nel.org, dmitry.baryshkov@...aro.org,
	fabrice.gasnier@...s.st.com, gregkh@...uxfoundation.org,
	hdegoede@...hat.com, neil.armstrong@...aro.org,
	rajaram.regupathy@...el.com, saranya.gopal@...el.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/4] usb: typec: ucsi: Register SOP/SOP' Discover
 Identity Responses

On Mar 05 02:58, Jameson Thies wrote:
> Register SOP and SOP' Discover Identity responses with the USB Type-C
> Connector Class as partner and cable identities, respectively. Discover
> Identity responses are requested from the PPM using the GET_PD_MESSAGE
> UCSI command.
> 
> Signed-off-by: Jameson Thies <jthies@...gle.com>

Mostly line splitting nits (which I have listed below). Once those are
addressed, please feel free to add:
Reviewed-by: Prashant Malani <pmalani@...omium.org>

> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index 7c84687b5d1a3..3b64a0f51041c 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -646,6 +646,108 @@ static int ucsi_get_src_pdos(struct ucsi_connector *con)
>  	return ret;
>  }
>  
> +static int ucsi_read_identity(struct ucsi_connector *con, u8 recipient,
> +			      u8 offset, u8 bytes, void *resp)
> +{
> +	struct ucsi *ucsi = con->ucsi;
> +	u64 command;
> +	int ret;
> +
> +	command = UCSI_COMMAND(UCSI_GET_PD_MESSAGE) |
> +	    UCSI_CONNECTOR_NUMBER(con->num);
> +	command |= UCSI_GET_PD_MESSAGE_RECIPIENT(recipient);
> +	command |= UCSI_GET_PD_MESSAGE_OFFSET(offset);
> +	command |= UCSI_GET_PD_MESSAGE_BYTES(bytes);
> +	command |= UCSI_GET_PD_MESSAGE_TYPE(UCSI_GET_PD_MESSAGE_TYPE_IDENTITY);
> +
> +	ret = ucsi_send_command(ucsi, command, resp, bytes);
> +	if (ret < 0)
> +		dev_err(ucsi->dev, "UCSI_GET_PD_MESSAGE failed (%d)\n", ret);
> +
> +	return ret;
> +}
> +
> +static int ucsi_get_identity(struct ucsi_connector *con, u8 recipient,
> +			      struct usb_pd_identity *id)

nit: Line limits are 100 now [1], so this can fit on one line.

> +{
> +	struct ucsi *ucsi = con->ucsi;
> +	struct ucsi_pd_message_disc_id resp = {};
> +	int ret;
> +
> +	if (ucsi->version < UCSI_VERSION_2_0) {
> +		/*
> +		 * Before UCSI v2.0, MESSAGE_IN is 16 bytes which cannot fit
> +		 * the 28 byte identity response including the VDM header.
> +		 * First request the VDM header, ID Header VDO, Cert Stat VDO
> +		 * and Product VDO.
> +		 */
> +		ret = ucsi_read_identity(con, recipient, 0, 0x10, &resp);
> +		if (ret < 0)
> +			return ret;
> +
> +
> +		/* Then request Product Type VDO1 through Product Type VDO3. */
> +		ret = ucsi_read_identity(con, recipient, 0x10, 0xc,
> +					 &resp.vdo[0]);

nit: Can fit on one line.

> +		if (ret < 0)
> +			return ret;
> +
> +	} else {
> +		/*
> +		 * In UCSI v2.0 and after, MESSAGE_IN is large enough to request
> +		 * the large enough to request the full Discover Identity
> +		 * response at once.
> +		 */
> +		ret = ucsi_read_identity(con, recipient, 0x0, 0x1c, &resp);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	id->id_header = resp.id_header;
> +	id->cert_stat = resp.cert_stat;
> +	id->product = resp.product;
> +	id->vdo[0] = resp.vdo[0];
> +	id->vdo[1] = resp.vdo[1];
> +	id->vdo[2] = resp.vdo[2];
> +	return 0;
> +}
> +
> +static int ucsi_get_partner_identity(struct ucsi_connector *con)
> +{
> +	int ret;
> +
> +	ret = ucsi_get_identity(con, UCSI_RECIPIENT_SOP,
> +				 &con->partner_identity);

nit: One line please.

> +	if (ret < 0)
> +		return ret;
> +
> +	ret = typec_partner_set_identity(con->partner);
> +	if (ret < 0) {
> +		dev_err(con->ucsi->dev, "Failed to set partner identity (%d)\n",
> +			ret);

nit: One line (100 is the limit now).

> +	}
> +
> +	return ret;
> +}
> +
> +static int ucsi_get_cable_identity(struct ucsi_connector *con)
> +{
> +	int ret;
> +
> +	ret = ucsi_get_identity(con, UCSI_RECIPIENT_SOP_P,
> +				 &con->cable_identity);

nit: One line.

> +	if (ret < 0)
> +		return ret;
> +
> +	ret = typec_cable_set_identity(con->cable);
> +	if (ret < 0) {
> +		dev_err(con->ucsi->dev, "Failed to set cable identity (%d)\n",
> +			ret);

nit: One line.

Best regards,

-Prashant

[1] https://github.com/torvalds/linux/blob/master/scripts/checkpatch.pl#L59