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Date:   Fri, 5 Jun 2020 02:12:46 -0700
From:   Prashant Malani <pmalani@chromium.org>
To:     linux-kernel@vger.kernel.org
Cc:     heikki.krogerus@linux.intel.com,
        Benson Leung <bleung@chromium.org>,
        Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Guenter Roeck <groeck@chromium.org>
Subject: Re: [PATCH 4/4] platform/chrome: typec: Support DP alt mode
Message-ID: <20200605091246.GC98441@google.com>
References: <20200528113607.120841-1-pmalani@chromium.org>
 <20200528113607.120841-5-pmalani@chromium.org>
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In-Reply-To: <20200528113607.120841-5-pmalani@chromium.org>
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Hi,
On Thu, May 28, 2020 at 04:36:10AM -0700, Prashant Malani wrote:
> Handle Chrome EC mux events to configure on-board muxes correctly while
> entering DP alternate mode. Since we don't surface SVID and VDO
> information regarding the DP alternate mode, configure the Type C
> muxes directly from the port driver. Later, when mode discovery
> information is correctly surfaced to the driver, we can register the DP
> alternate mode driver and let it handle the mux configuration.
> 
> Also, modify the struct_typec_state state management to account for the
> addition of DP alternate mode.
> 
> Signed-off-by: Prashant Malani <pmalani@chromium.org>
Sorry, forgot to mention (and will add to subsequent versions):
Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/platform/chrome/cros_ec_typec.c | 90 ++++++++++++++++++++++---
>  1 file changed, 80 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 9ebf9abed16f..509fc761906b 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -15,11 +15,18 @@
>  #include <linux/platform_device.h>
>  #include <linux/usb/typec.h>
>  #include <linux/usb/typec_altmode.h>
> +#include <linux/usb/typec_dp.h>
>  #include <linux/usb/typec_mux.h>
>  #include <linux/usb/role.h>
>  
>  #define DRV_NAME "cros-ec-typec"
>  
> +/* Supported alt modes. */
> +enum {
> +	CROS_EC_ALTMODE_DP = 0,
> +	CROS_EC_ALTMODE_MAX,
> +};
> +
>  /* Per port data. */
>  struct cros_typec_port {
>  	struct typec_port *port;
> @@ -35,6 +42,9 @@ struct cros_typec_port {
>  	/* Variables keeping track of switch state. */
>  	struct typec_mux_state state;
>  	uint8_t mux_flags;
> +
> +	/* Port alt modes. */
> +	struct typec_altmode p_altmode[CROS_EC_ALTMODE_MAX];
>  };
>  
>  /* Platform-specific data for the Chrome OS EC Type C controller. */
> @@ -142,6 +152,24 @@ static void cros_unregister_ports(struct cros_typec_data *typec)
>  	}
>  }
>  
> +/*
> + * Fake the alt mode structs until we actually start registering Type C port
> + * and partner alt modes.
> + */
> +static void cros_typec_register_port_altmodes(struct cros_typec_data *typec,
> +					      int port_num)
> +{
> +	struct cros_typec_port *port = typec->ports[port_num];
> +
> +	/* All PD capable CrOS devices are assumed to support DP altmode. */
> +	port->p_altmode[CROS_EC_ALTMODE_DP].svid = USB_TYPEC_DP_SID;
> +	port->p_altmode[CROS_EC_ALTMODE_DP].mode = USB_TYPEC_DP_MODE;
> +
> +	port->state.alt = NULL;
> +	port->state.mode = TYPEC_STATE_USB;
> +	port->state.data = NULL;
> +}
> +
>  static int cros_typec_init_ports(struct cros_typec_data *typec)
>  {
>  	struct device *dev = typec->dev;
> @@ -205,6 +233,8 @@ static int cros_typec_init_ports(struct cros_typec_data *typec)
>  		if (ret)
>  			dev_dbg(dev, "No switch control for port %d\n",
>  				port_num);
> +
> +		cros_typec_register_port_altmodes(typec, port_num);
>  	}
>  
>  	return 0;
> @@ -361,8 +391,46 @@ static int cros_typec_usb_safe_state(struct cros_typec_port *port)
>  	return typec_mux_set(port->mux, &port->state);
>  }
>  
> +/* Spoof the VDOs that were likely communicated by the partner. */
> +static int cros_typec_enable_dp(struct cros_typec_data *typec,
> +				int port_num,
> +				struct ec_response_usb_pd_control_v2 *pd_ctrl)
> +{
> +	struct cros_typec_port *port = typec->ports[port_num];
> +	struct typec_displayport_data dp_data;
> +	int ret;
> +
> +	if (typec->pd_ctrl_ver < 2) {
> +		dev_err(typec->dev,
> +			"PD_CTRL version too old: %d\n", typec->pd_ctrl_ver);
> +		return -ENOTSUPP;
> +	}
> +
> +	/* Status VDO. */
> +	dp_data.status = DP_STATUS_ENABLED;
> +	if (port->mux_flags & USB_PD_MUX_HPD_IRQ)
> +		dp_data.status |= DP_STATUS_IRQ_HPD;
> +	if (port->mux_flags & USB_PD_MUX_HPD_LVL)
> +		dp_data.status |= DP_STATUS_HPD_STATE;
> +
> +	/* Configuration VDO. */
> +	dp_data.conf = DP_CONF_SET_PIN_ASSIGN(pd_ctrl->dp_mode);
> +	if (!port->state.alt) {
> +		port->state.alt = &port->p_altmode[CROS_EC_ALTMODE_DP];
> +		ret = cros_typec_usb_safe_state(port);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	port->state.data = &dp_data;
> +	port->state.mode = TYPEC_MODAL_STATE(ffs(pd_ctrl->dp_mode));
> +
> +	return typec_mux_set(port->mux, &port->state);
> +}
> +
>  int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
> -			     uint8_t mux_flags)
> +			     uint8_t mux_flags,
> +			     struct ec_response_usb_pd_control_v2 *pd_ctrl)
>  {
>  	struct cros_typec_port *port = typec->ports[port_num];
>  	enum typec_orientation orientation;
> @@ -380,14 +448,15 @@ int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>  	if (ret)
>  		return ret;
>  
> -	port->state.alt = NULL;
> -	port->state.mode = TYPEC_STATE_USB;
> -
> -	if (mux_flags & USB_PD_MUX_SAFE_MODE)
> +	if (mux_flags & USB_PD_MUX_DP_ENABLED) {
> +		ret = cros_typec_enable_dp(typec, port_num, pd_ctrl);
> +	} else if (mux_flags & USB_PD_MUX_SAFE_MODE) {
>  		ret = cros_typec_usb_safe_state(port);
> -	else if (mux_flags & USB_PD_MUX_USB_ENABLED)
> +	} else if (mux_flags & USB_PD_MUX_USB_ENABLED) {
> +		port->state.alt = NULL;
> +		port->state.mode = TYPEC_STATE_USB;
>  		ret = typec_mux_set(port->mux, &port->state);
> -	else {
> +	} else {
>  		dev_info(typec->dev,
>  			 "Unsupported mode requested, mux flags: %x\n",
>  			 mux_flags);
> @@ -400,7 +469,7 @@ int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>  static int cros_typec_port_update(struct cros_typec_data *typec, int port_num)
>  {
>  	struct ec_params_usb_pd_control req;
> -	struct ec_response_usb_pd_control_v1 resp;
> +	struct ec_response_usb_pd_control_v2 resp;
>  	struct ec_response_usb_pd_mux_info mux_resp;
>  	int ret;
>  
> @@ -427,7 +496,8 @@ static int cros_typec_port_update(struct cros_typec_data *typec, int port_num)
>  	dev_dbg(typec->dev, "State %d: %s\n", port_num, resp.state);
>  
>  	if (typec->pd_ctrl_ver != 0)
> -		cros_typec_set_port_params_v1(typec, port_num, &resp);
> +		cros_typec_set_port_params_v1(typec, port_num,
> +			(struct ec_response_usb_pd_control_v1 *)&resp);
>  	else
>  		cros_typec_set_port_params_v0(typec, port_num,
>  			(struct ec_response_usb_pd_control *) &resp);
> @@ -446,7 +516,7 @@ static int cros_typec_port_update(struct cros_typec_data *typec, int port_num)
>  		return 0;
>  
>  	typec->ports[port_num]->mux_flags = mux_resp.flags;
> -	ret = cros_typec_configure_mux(typec, port_num, mux_resp.flags);
> +	ret = cros_typec_configure_mux(typec, port_num, mux_resp.flags, &resp);
>  	if (ret)
>  		dev_warn(typec->dev, "Configure muxes failed, err = %d\n", ret);
>  
> -- 
> 2.27.0.rc0.183.gde8f92d652-goog
>