soc: qcom: pmic_glink_altmode: add retimer-switch support

Some boards have a retimer/redriver between the SuperSpeed
PHY and the USB-C connector to compensates signal integrity
losses mainly due to PCB & transmission cables.

Add support for an optional retimer-switch in the USB-C
connector graph.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230601-topic-sm8550-upstream-type-c-v5-2-9221cd300903@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

drivers/soc/qcom/pmic_glink_altmode.c

@@ -16,6 +16,7 @@
 #include <linux/usb/typec_altmode.h>
 #include <linux/usb/typec_dp.h>
 #include <linux/usb/typec_mux.h>
+#include <linux/usb/typec_retimer.h>
 
 #include <linux/soc/qcom/pmic_glink.h>
 
@@ -69,6 +70,8 @@ struct pmic_glink_altmode_port {
 	struct typec_switch *typec_switch;
 	struct typec_mux *typec_mux;
 	struct typec_mux_state state;
+	struct typec_retimer *typec_retimer;
+	struct typec_retimer_state retimer_state;
 	struct typec_altmode dp_alt;
 
 	struct work_struct work;
@@ -158,6 +161,14 @@ static void pmic_glink_altmode_enable_dp(struct pmic_glink_altmode *altmode,
 	ret = typec_mux_set(port->typec_mux, &port->state);
 	if (ret)
 		dev_err(altmode->dev, "failed to switch mux to DP\n");
+
+	port->retimer_state.alt = &port->dp_alt;
+	port->retimer_state.data = &dp_data;
+	port->retimer_state.mode = TYPEC_MODAL_STATE(mode);
+
+	ret = typec_retimer_set(port->typec_retimer, &port->retimer_state);
+	if (ret)
+		dev_err(altmode->dev, "failed to setup retimer to DP\n");
 }
 
 static void pmic_glink_altmode_enable_usb(struct pmic_glink_altmode *altmode,
@@ -172,6 +183,14 @@ static void pmic_glink_altmode_enable_usb(struct pmic_glink_altmode *altmode,
 	ret = typec_mux_set(port->typec_mux, &port->state);
 	if (ret)
 		dev_err(altmode->dev, "failed to switch mux to USB\n");
+
+	port->retimer_state.alt = NULL;
+	port->retimer_state.data = NULL;
+	port->retimer_state.mode = TYPEC_STATE_USB;
+
+	ret = typec_retimer_set(port->typec_retimer, &port->retimer_state);
+	if (ret)
+		dev_err(altmode->dev, "failed to setup retimer to USB\n");
 }
 
 static void pmic_glink_altmode_safe(struct pmic_glink_altmode *altmode,
@@ -186,6 +205,14 @@ static void pmic_glink_altmode_safe(struct pmic_glink_altmode *altmode,
 	ret = typec_mux_set(port->typec_mux, &port->state);
 	if (ret)
 		dev_err(altmode->dev, "failed to switch mux to safe mode\n");
+
+	port->retimer_state.alt = NULL;
+	port->retimer_state.data = NULL;
+	port->retimer_state.mode = TYPEC_STATE_SAFE;
+
+	ret = typec_retimer_set(port->typec_retimer, &port->retimer_state);
+	if (ret)
+		dev_err(altmode->dev, "failed to setup retimer to USB\n");
 }
 
 static void pmic_glink_altmode_worker(struct work_struct *work)
@@ -348,6 +375,11 @@ static const struct drm_bridge_funcs pmic_glink_altmode_bridge_funcs = {
 	.attach = pmic_glink_altmode_attach,
 };
 
+static void pmic_glink_altmode_put_retimer(void *data)
+{
+	typec_retimer_put(data);
+}
+
 static void pmic_glink_altmode_put_mux(void *data)
 {
 	typec_mux_put(data);
@@ -454,6 +486,17 @@ static int pmic_glink_altmode_probe(struct auxiliary_device *adev,
 		if (ret)
 			return ret;
 
+		alt_port->typec_retimer = fwnode_typec_retimer_get(fwnode);
+		if (IS_ERR(alt_port->typec_retimer))
+			return dev_err_probe(dev, PTR_ERR(alt_port->typec_retimer),
+					     "failed to acquire retimer-switch for port: %d\n",
+					     port);
+
+		ret = devm_add_action_or_reset(dev, pmic_glink_altmode_put_retimer,
+					       alt_port->typec_retimer);
+		if (ret)
+			return ret;
+
 		alt_port->typec_switch = fwnode_typec_switch_get(fwnode);
 		if (IS_ERR(alt_port->typec_switch))
 			return dev_err_probe(dev, PTR_ERR(alt_port->typec_switch),