[PATCH v1 1/4] usb: typec: tcpm: Fix up PR_SWAP when vsafe0v is signalled

[PATCH v1 1/4] usb: typec: tcpm: Fix up PR_SWAP when vsafe0v is signalled

[Badhri Jagan Sridharan]

During PR_SWAP, When TCPM is in PR_SWAP_SNK_SRC_SINK_OFF, vbus is
expected to reach VSAFE0V when source turns of vbus. Do not move
to SNK_UNATTACHED state when this happens.

Fixes: 28b43d3d746b ("usb: typec: tcpm: Introduce vsafe0v for vbus")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index c4fdc00a3bc8..b93c4c8d7b15 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -5114,6 +5114,9 @@ static void _tcpm_pd_vbus_vsafe0v(struct tcpm_port *port)
 				tcpm_set_state(port, SNK_UNATTACHED, 0);
 		}
 		break;
+	case PR_SWAP_SNK_SRC_SINK_OFF:
+		/* Do nothing, vsafe0v is expected during transition */
+		break;
 	default:
 		if (port->pwr_role == TYPEC_SINK && port->auto_vbus_discharge_enabled)
 			tcpm_set_state(port, SNK_UNATTACHED, 0);
-- 
2.31.1.751.gd2f1c929bd-goog

[PATCH v1 2/4] usb: typec: tcpm: Refactor logic to enable/disable auto vbus dicharge

[Badhri Jagan Sridharan]

The logic to enable vbus auto discharge on disconnect is used in
more than one place. Since this is repetitive code, moving this into
its own method.

Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 39 ++++++++++++++++-------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index b93c4c8d7b15..b475d9b9d38d 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -771,6 +771,21 @@ static void tcpm_set_cc(struct tcpm_port *port, enum typec_cc_status cc)
 	port->tcpc->set_cc(port->tcpc, cc);
 }
 
+static int tcpm_enable_auto_vbus_discharge(struct tcpm_port *port, bool enable)
+{
+	int ret = 0;
+
+	if (port->tcpc->enable_auto_vbus_discharge) {
+		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, enable);
+		tcpm_log_force(port, "%s vbus discharge ret:%d", enable ? "enable" : "disable",
+			       ret);
+		if (!ret)
+			port->auto_vbus_discharge_enabled = enable;
+	}
+
+	return ret;
+}
+
 /*
  * Determine RP value to set based on maximum current supported
  * by a port if configured as source.
@@ -3445,12 +3460,7 @@ static int tcpm_src_attach(struct tcpm_port *port)
 	if (ret < 0)
 		return ret;
 
-	if (port->tcpc->enable_auto_vbus_discharge) {
-		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, true);
-		tcpm_log_force(port, "enable vbus discharge ret:%d", ret);
-		if (!ret)
-			port->auto_vbus_discharge_enabled = true;
-	}
+	tcpm_enable_auto_vbus_discharge(port, true);
 
 	ret = tcpm_set_roles(port, true, TYPEC_SOURCE, tcpm_data_role_for_source(port));
 	if (ret < 0)
@@ -3527,14 +3537,7 @@ static void tcpm_set_partner_usb_comm_capable(struct tcpm_port *port, bool capab
 
 static void tcpm_reset_port(struct tcpm_port *port)
 {
-	int ret;
-
-	if (port->tcpc->enable_auto_vbus_discharge) {
-		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, false);
-		tcpm_log_force(port, "Disable vbus discharge ret:%d", ret);
-		if (!ret)
-			port->auto_vbus_discharge_enabled = false;
-	}
+	tcpm_enable_auto_vbus_discharge(port, false);
 	port->in_ams = false;
 	port->ams = NONE_AMS;
 	port->vdm_sm_running = false;
@@ -3602,13 +3605,7 @@ static int tcpm_snk_attach(struct tcpm_port *port)
 	if (ret < 0)
 		return ret;
 
-	if (port->tcpc->enable_auto_vbus_discharge) {
-		tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);
-		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, true);
-		tcpm_log_force(port, "enable vbus discharge ret:%d", ret);
-		if (!ret)
-			port->auto_vbus_discharge_enabled = true;
-	}
+	tcpm_enable_auto_vbus_discharge(port, true);
 
 	ret = tcpm_set_roles(port, true, TYPEC_SINK, tcpm_data_role_for_sink(port));
 	if (ret < 0)
-- 
2.31.1.751.gd2f1c929bd-goog

[PATCH v1 3/4] usb: typec: tcpm: Move TCPC to APPLY_RC state during PR_SWAP

[Badhri Jagan Sridharan]

When vbus auto discharge is enabled, TCPCI based TCPC transitions
into Attached.SNK/Attached.SRC state. During PR_SWAP, TCPCI based
TCPC would disconnect when partner changes power roles. TCPC has
to be moved APPLY RC state during PR_SWAP. This is done by
ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and
POWER_CONTROL.AutodischargeDisconnect is 0. Once the swap sequence
is done, AutoDischargeDisconnect is re-enabled.

Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 16 ++++++++++++++++
 include/linux/usb/tcpm.h      |  4 ++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index b475d9b9d38d..5bac4978efb3 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -786,6 +786,19 @@ static int tcpm_enable_auto_vbus_discharge(struct tcpm_port *port, bool enable)
 	return ret;
 }
 
+static void tcpm_apply_rc(struct tcpm_port *port)
+{
+	/*
+	 * TCPCI: Move to APPLY_RC state to prevent disconnect during PR_SWAP
+	 * when Vbus auto discharge on disconnect is enabled.
+	 */
+	if (port->tcpc->enable_auto_vbus_discharge) {
+		tcpm_log(port, "Apply_RC");
+		port->tcpc->apply_rc(port->tcpc, port->cc_req, port->polarity);
+		tcpm_enable_auto_vbus_discharge(port, false);
+	}
+}
+
 /*
  * Determine RP value to set based on maximum current supported
  * by a port if configured as source.
@@ -4428,6 +4441,7 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_set_state(port, ready_state(port), 0);
 		break;
 	case PR_SWAP_START:
+		tcpm_apply_rc(port);
 		if (port->pwr_role == TYPEC_SOURCE)
 			tcpm_set_state(port, PR_SWAP_SRC_SNK_TRANSITION_OFF,
 				       PD_T_SRC_TRANSITION);
@@ -4467,6 +4481,7 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_set_state(port, ERROR_RECOVERY, PD_T_PS_SOURCE_ON_PRS);
 		break;
 	case PR_SWAP_SRC_SNK_SINK_ON:
+		tcpm_enable_auto_vbus_discharge(port, true);
 		/* Set the vbus disconnect threshold for implicit contract */
 		tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);
 		tcpm_set_state(port, SNK_STARTUP, 0);
@@ -4483,6 +4498,7 @@ static void run_state_machine(struct tcpm_port *port)
 			       PD_T_PS_SOURCE_OFF);
 		break;
 	case PR_SWAP_SNK_SRC_SOURCE_ON:
+		tcpm_enable_auto_vbus_discharge(port, true);
 		tcpm_set_cc(port, tcpm_rp_cc(port));
 		tcpm_set_vbus(port, true);
 		/*
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index 42fcfbe10590..bffc8d3e14ad 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -66,6 +66,8 @@ enum tcpm_transmit_type {
  *		For example, some tcpcs may include BC1.2 charger detection
  *		and use that in this case.
  * @set_cc:	Called to set value of CC pins
+ * @apply_rc:	Optional; Needed to move TCPCI based chipset to APPLY_RC state
+ *		as stated by the TCPCI specification.
  * @get_cc:	Called to read current CC pin values
  * @set_polarity:
  *		Called to set polarity
@@ -120,6 +122,8 @@ struct tcpc_dev {
 	int (*get_vbus)(struct tcpc_dev *dev);
 	int (*get_current_limit)(struct tcpc_dev *dev);
 	int (*set_cc)(struct tcpc_dev *dev, enum typec_cc_status cc);
+	int (*apply_rc)(struct tcpc_dev *dev, enum typec_cc_status cc,
+			enum typec_cc_polarity polarity);
 	int (*get_cc)(struct tcpc_dev *dev, enum typec_cc_status *cc1,
 		      enum typec_cc_status *cc2);
 	int (*set_polarity)(struct tcpc_dev *dev,
-- 
2.31.1.751.gd2f1c929bd-goog

[PATCH v1 4/4] usb: typec: tcpci: Implement callback for apply_rc

[Badhri Jagan Sridharan]

APPLY RC is defined as ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and
POWER_CONTROL.AutodischargeDisconnect is 0. When ROLE_CONTROL.CC1 ==
ROLE_CONTROL.CC2, set the other CC to OPEN.

Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpci.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index 25b480752266..34b5095cc84f 100644
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -115,6 +115,32 @@ static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc)
 	return 0;
 }
 
+int tcpci_apply_rc(struct tcpc_dev *tcpc, enum typec_cc_status cc, enum typec_cc_polarity polarity)
+{
+	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(tcpci->regmap, TCPC_ROLE_CTRL, &reg);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * APPLY_RC state is when ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and vbus autodischarge on
+	 * disconnect is disabled. Bail out when ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2.
+	 */
+	if (((reg & (TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT)) >>
+	     TCPC_ROLE_CTRL_CC2_SHIFT) !=
+	    ((reg & (TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT)) >>
+	     TCPC_ROLE_CTRL_CC1_SHIFT))
+		return 0;
+
+	return regmap_update_bits(tcpci->regmap, TCPC_ROLE_CTRL, polarity == TYPEC_POLARITY_CC1 ?
+				  TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT :
+				  TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT,
+				  TCPC_ROLE_CTRL_CC_OPEN);
+}
+
 static int tcpci_start_toggling(struct tcpc_dev *tcpc,
 				enum typec_port_type port_type,
 				enum typec_cc_status cc)
@@ -728,6 +754,7 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
 	tcpci->tcpc.get_vbus = tcpci_get_vbus;
 	tcpci->tcpc.set_vbus = tcpci_set_vbus;
 	tcpci->tcpc.set_cc = tcpci_set_cc;
+	tcpci->tcpc.apply_rc = tcpci_apply_rc;
 	tcpci->tcpc.get_cc = tcpci_get_cc;
 	tcpci->tcpc.set_polarity = tcpci_set_polarity;
 	tcpci->tcpc.set_vconn = tcpci_set_vconn;
-- 
2.31.1.751.gd2f1c929bd-goog

Re: [PATCH v1 1/4] usb: typec: tcpm: Fix up PR_SWAP when vsafe0v is signalled

[Peter Chen]

On 21-05-14 22:26:10, Badhri Jagan Sridharan wrote:
> During PR_SWAP, When TCPM is in PR_SWAP_SNK_SRC_SINK_OFF, vbus is
> expected to reach VSAFE0V when source turns of vbus. Do not move

%s/of/off

Peter

> to SNK_UNATTACHED state when this happens.
> 
> Fixes: 28b43d3d746b ("usb: typec: tcpm: Introduce vsafe0v for vbus")
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index c4fdc00a3bc8..b93c4c8d7b15 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -5114,6 +5114,9 @@ static void _tcpm_pd_vbus_vsafe0v(struct tcpm_port *port)
>  				tcpm_set_state(port, SNK_UNATTACHED, 0);
>  		}
>  		break;
> +	case PR_SWAP_SNK_SRC_SINK_OFF:
> +		/* Do nothing, vsafe0v is expected during transition */
> +		break;
>  	default:
>  		if (port->pwr_role == TYPEC_SINK && port->auto_vbus_discharge_enabled)
>  			tcpm_set_state(port, SNK_UNATTACHED, 0);
> -- 
> 2.31.1.751.gd2f1c929bd-goog
> 

-- 

Thanks,
Peter Chen

Re: [PATCH v1 1/4] usb: typec: tcpm: Fix up PR_SWAP when vsafe0v is signalled

[Guenter Roeck]

On Fri, May 14, 2021 at 10:26:10PM -0700, Badhri Jagan Sridharan wrote:
> During PR_SWAP, When TCPM is in PR_SWAP_SNK_SRC_SINK_OFF, vbus is
> expected to reach VSAFE0V when source turns of vbus. Do not move

s/of/off/ as already reported

> to SNK_UNATTACHED state when this happens.
> 
> Fixes: 28b43d3d746b ("usb: typec: tcpm: Introduce vsafe0v for vbus")
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>

Otherwise

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index c4fdc00a3bc8..b93c4c8d7b15 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -5114,6 +5114,9 @@ static void _tcpm_pd_vbus_vsafe0v(struct tcpm_port *port)
>  				tcpm_set_state(port, SNK_UNATTACHED, 0);
>  		}
>  		break;
> +	case PR_SWAP_SNK_SRC_SINK_OFF:
> +		/* Do nothing, vsafe0v is expected during transition */
> +		break;
>  	default:
>  		if (port->pwr_role == TYPEC_SINK && port->auto_vbus_discharge_enabled)
>  			tcpm_set_state(port, SNK_UNATTACHED, 0);
> -- 
> 2.31.1.751.gd2f1c929bd-goog
> 

Re: [PATCH v1 2/4] usb: typec: tcpm: Refactor logic to enable/disable auto vbus dicharge

[Guenter Roeck]

On Fri, May 14, 2021 at 10:26:11PM -0700, Badhri Jagan Sridharan wrote:
> The logic to enable vbus auto discharge on disconnect is used in
> more than one place. Since this is repetitive code, moving this into
> its own method.
> 
> Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/usb/typec/tcpm/tcpm.c | 39 ++++++++++++++++-------------------
>  1 file changed, 18 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index b93c4c8d7b15..b475d9b9d38d 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -771,6 +771,21 @@ static void tcpm_set_cc(struct tcpm_port *port, enum typec_cc_status cc)
>  	port->tcpc->set_cc(port->tcpc, cc);
>  }
>  
> +static int tcpm_enable_auto_vbus_discharge(struct tcpm_port *port, bool enable)
> +{
> +	int ret = 0;
> +
> +	if (port->tcpc->enable_auto_vbus_discharge) {
> +		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, enable);
> +		tcpm_log_force(port, "%s vbus discharge ret:%d", enable ? "enable" : "disable",
> +			       ret);
> +		if (!ret)
> +			port->auto_vbus_discharge_enabled = enable;
> +	}
> +
> +	return ret;
> +}
> +
>  /*
>   * Determine RP value to set based on maximum current supported
>   * by a port if configured as source.
> @@ -3445,12 +3460,7 @@ static int tcpm_src_attach(struct tcpm_port *port)
>  	if (ret < 0)
>  		return ret;
>  
> -	if (port->tcpc->enable_auto_vbus_discharge) {
> -		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, true);
> -		tcpm_log_force(port, "enable vbus discharge ret:%d", ret);
> -		if (!ret)
> -			port->auto_vbus_discharge_enabled = true;
> -	}
> +	tcpm_enable_auto_vbus_discharge(port, true);
>  
>  	ret = tcpm_set_roles(port, true, TYPEC_SOURCE, tcpm_data_role_for_source(port));
>  	if (ret < 0)
> @@ -3527,14 +3537,7 @@ static void tcpm_set_partner_usb_comm_capable(struct tcpm_port *port, bool capab
>  
>  static void tcpm_reset_port(struct tcpm_port *port)
>  {
> -	int ret;
> -
> -	if (port->tcpc->enable_auto_vbus_discharge) {
> -		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, false);
> -		tcpm_log_force(port, "Disable vbus discharge ret:%d", ret);
> -		if (!ret)
> -			port->auto_vbus_discharge_enabled = false;
> -	}
> +	tcpm_enable_auto_vbus_discharge(port, false);
>  	port->in_ams = false;
>  	port->ams = NONE_AMS;
>  	port->vdm_sm_running = false;
> @@ -3602,13 +3605,7 @@ static int tcpm_snk_attach(struct tcpm_port *port)
>  	if (ret < 0)
>  		return ret;
>  
> -	if (port->tcpc->enable_auto_vbus_discharge) {
> -		tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);
> -		ret = port->tcpc->enable_auto_vbus_discharge(port->tcpc, true);
> -		tcpm_log_force(port, "enable vbus discharge ret:%d", ret);
> -		if (!ret)
> -			port->auto_vbus_discharge_enabled = true;
> -	}
> +	tcpm_enable_auto_vbus_discharge(port, true);
>  
>  	ret = tcpm_set_roles(port, true, TYPEC_SINK, tcpm_data_role_for_sink(port));
>  	if (ret < 0)
> -- 
> 2.31.1.751.gd2f1c929bd-goog
> 

Re: [PATCH v1 3/4] usb: typec: tcpm: Move TCPC to APPLY_RC state during PR_SWAP

[Guenter Roeck]

On 5/14/21 10:26 PM, Badhri Jagan Sridharan wrote:
> When vbus auto discharge is enabled, TCPCI based TCPC transitions
> into Attached.SNK/Attached.SRC state. During PR_SWAP, TCPCI based
> TCPC would disconnect when partner changes power roles. TCPC has
> to be moved APPLY RC state during PR_SWAP. This is done by
> ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and
> POWER_CONTROL.AutodischargeDisconnect is 0. Once the swap sequence
> is done, AutoDischargeDisconnect is re-enabled.
> 
> Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> ---
>   drivers/usb/typec/tcpm/tcpm.c | 16 ++++++++++++++++
>   include/linux/usb/tcpm.h      |  4 ++++
>   2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index b475d9b9d38d..5bac4978efb3 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -786,6 +786,19 @@ static int tcpm_enable_auto_vbus_discharge(struct tcpm_port *port, bool enable)
>   	return ret;
>   }
>   
> +static void tcpm_apply_rc(struct tcpm_port *port)
> +{
> +	/*
> +	 * TCPCI: Move to APPLY_RC state to prevent disconnect during PR_SWAP
> +	 * when Vbus auto discharge on disconnect is enabled.
> +	 */
> +	if (port->tcpc->enable_auto_vbus_discharge) {
> +		tcpm_log(port, "Apply_RC");
> +		port->tcpc->apply_rc(port->tcpc, port->cc_req, port->polarity);

This is called unconditionally. I think you'll need an additional
		&& port->tcpc->apply_rc
in the if statement above.

> +		tcpm_enable_auto_vbus_discharge(port, false);
> +	}
> +}
> +
>   /*
>    * Determine RP value to set based on maximum current supported
>    * by a port if configured as source.
> @@ -4428,6 +4441,7 @@ static void run_state_machine(struct tcpm_port *port)
>   		tcpm_set_state(port, ready_state(port), 0);
>   		break;
>   	case PR_SWAP_START:
> +		tcpm_apply_rc(port);
>   		if (port->pwr_role == TYPEC_SOURCE)
>   			tcpm_set_state(port, PR_SWAP_SRC_SNK_TRANSITION_OFF,
>   				       PD_T_SRC_TRANSITION);
> @@ -4467,6 +4481,7 @@ static void run_state_machine(struct tcpm_port *port)
>   		tcpm_set_state(port, ERROR_RECOVERY, PD_T_PS_SOURCE_ON_PRS);
>   		break;
>   	case PR_SWAP_SRC_SNK_SINK_ON:
> +		tcpm_enable_auto_vbus_discharge(port, true);
>   		/* Set the vbus disconnect threshold for implicit contract */
>   		tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);
>   		tcpm_set_state(port, SNK_STARTUP, 0);
> @@ -4483,6 +4498,7 @@ static void run_state_machine(struct tcpm_port *port)
>   			       PD_T_PS_SOURCE_OFF);
>   		break;
>   	case PR_SWAP_SNK_SRC_SOURCE_ON:
> +		tcpm_enable_auto_vbus_discharge(port, true);
>   		tcpm_set_cc(port, tcpm_rp_cc(port));
>   		tcpm_set_vbus(port, true);
>   		/*
> diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
> index 42fcfbe10590..bffc8d3e14ad 100644
> --- a/include/linux/usb/tcpm.h
> +++ b/include/linux/usb/tcpm.h
> @@ -66,6 +66,8 @@ enum tcpm_transmit_type {
>    *		For example, some tcpcs may include BC1.2 charger detection
>    *		and use that in this case.
>    * @set_cc:	Called to set value of CC pins
> + * @apply_rc:	Optional; Needed to move TCPCI based chipset to APPLY_RC state
> + *		as stated by the TCPCI specification.
>    * @get_cc:	Called to read current CC pin values
>    * @set_polarity:
>    *		Called to set polarity
> @@ -120,6 +122,8 @@ struct tcpc_dev {
>   	int (*get_vbus)(struct tcpc_dev *dev);
>   	int (*get_current_limit)(struct tcpc_dev *dev);
>   	int (*set_cc)(struct tcpc_dev *dev, enum typec_cc_status cc);
> +	int (*apply_rc)(struct tcpc_dev *dev, enum typec_cc_status cc,
> +			enum typec_cc_polarity polarity);
>   	int (*get_cc)(struct tcpc_dev *dev, enum typec_cc_status *cc1,
>   		      enum typec_cc_status *cc2);
>   	int (*set_polarity)(struct tcpc_dev *dev,
> 

Re: [PATCH v1 4/4] usb: typec: tcpci: Implement callback for apply_rc

[Guenter Roeck]

On Fri, May 14, 2021 at 10:26:13PM -0700, Badhri Jagan Sridharan wrote:
> APPLY RC is defined as ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and
> POWER_CONTROL.AutodischargeDisconnect is 0. When ROLE_CONTROL.CC1 ==
> ROLE_CONTROL.CC2, set the other CC to OPEN.
> 
> Fixes: f321a02caebd ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/usb/typec/tcpm/tcpci.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> index 25b480752266..34b5095cc84f 100644
> --- a/drivers/usb/typec/tcpm/tcpci.c
> +++ b/drivers/usb/typec/tcpm/tcpci.c
> @@ -115,6 +115,32 @@ static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc)
>  	return 0;
>  }
>  
> +int tcpci_apply_rc(struct tcpc_dev *tcpc, enum typec_cc_status cc, enum typec_cc_polarity polarity)
> +{
> +	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> +	unsigned int reg;
> +	int ret;
> +
> +	ret = regmap_read(tcpci->regmap, TCPC_ROLE_CTRL, &reg);
> +	if (ret < 0)
> +		return ret;
> +
> +	/*
> +	 * APPLY_RC state is when ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and vbus autodischarge on
> +	 * disconnect is disabled. Bail out when ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2.
> +	 */
> +	if (((reg & (TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT)) >>
> +	     TCPC_ROLE_CTRL_CC2_SHIFT) !=
> +	    ((reg & (TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT)) >>
> +	     TCPC_ROLE_CTRL_CC1_SHIFT))
> +		return 0;
> +
> +	return regmap_update_bits(tcpci->regmap, TCPC_ROLE_CTRL, polarity == TYPEC_POLARITY_CC1 ?
> +				  TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT :
> +				  TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT,
> +				  TCPC_ROLE_CTRL_CC_OPEN);
> +}
> +
>  static int tcpci_start_toggling(struct tcpc_dev *tcpc,
>  				enum typec_port_type port_type,
>  				enum typec_cc_status cc)
> @@ -728,6 +754,7 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
>  	tcpci->tcpc.get_vbus = tcpci_get_vbus;
>  	tcpci->tcpc.set_vbus = tcpci_set_vbus;
>  	tcpci->tcpc.set_cc = tcpci_set_cc;
> +	tcpci->tcpc.apply_rc = tcpci_apply_rc;
>  	tcpci->tcpc.get_cc = tcpci_get_cc;
>  	tcpci->tcpc.set_polarity = tcpci_set_polarity;
>  	tcpci->tcpc.set_vconn = tcpci_set_vconn;
> -- 
> 2.31.1.751.gd2f1c929bd-goog
>