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

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Date: Wed, 27 Mar 2024 13:18:42 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Prashant Malani <pmalani@...omium.org>
Cc: Jameson Thies <jthies@...gle.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 Tue, Mar 05, 2024 at 06:54:39PM +0000, Prashant Malani wrote:
> 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>

After you've fixed those add also my:
Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> > 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

-- 
heikki