Some EC firmwares on Trogdor/Strongbad boards don't properly indicate
the state of DP HPD on a type-c port. Instead, the EC only indicates
that DP mode is entered or exited for a type-c port. To make matters
worse, on these firmwares the DP signal is muxed between two USB type-c
connectors, so we can't use the HPD state to figure out which type-c
port is actually displaying DP.
Read the state of the EC's analog mux from the hpd notification callback
to figure out which type-c port is displaying DP. This circumvents the
entire host command/message interface, because it doesn't work all the
time. Only do this when we have the mux-gpios property in DT, indicating
that we have to read the EC gpio state to figure this out. For now we
only support a single gpio "bit", so there can only be two USB type-c
ports.
Cc: Prashant Malani <pmalani@xxxxxxxxxxxx>
Cc: Benson Leung <bleung@xxxxxxxxxxxx>
Cc: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
Cc: <chrome-platform@xxxxxxxxxxxxxxx>
Cc: Pin-yen Lin <treapking@xxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
drivers/platform/chrome/cros_typec_switch.c | 33 ++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
index c22c2531327a..edd628eab7da 100644
--- a/drivers/platform/chrome/cros_typec_switch.c
+++ b/drivers/platform/chrome/cros_typec_switch.c
@@ -8,6 +8,7 @@
#include <linux/acpi.h>
#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -26,6 +27,7 @@
struct cros_typec_dp_bridge {
/* TODO: Add mutex lock to protect active_port with respect to drm/typec framework calls */
struct cros_typec_port *active_port;
+ struct gpio_desc *mux_gpio;
struct cros_typec_switch_data *sdata;
size_t max_lanes;
bool hpd_enabled;
@@ -453,6 +455,29 @@ static void cros_typec_dp_bridge_hpd_disable(struct drm_bridge *bridge)
typec_dp_bridge->hpd_enabled = false;
}
+static void cros_typec_dp_bridge_hpd_notify(struct drm_bridge *bridge,
+ enum drm_connector_status status)
+{
+ struct cros_typec_dp_bridge *typec_dp_bridge;
+ struct cros_typec_switch_data *sdata;
+ struct gpio_desc *mux_gpio;
+ int mux_val;
+
+ typec_dp_bridge = bridge_to_cros_typec_dp_bridge(bridge);
+ mux_gpio = typec_dp_bridge->mux_gpio;
+
+ /*
+ * Some ECs don't notify AP when HPD goes high or low so we have to
+ * read the EC GPIO that controls the mux to figure out which type-c
+ * port is connected to DP.
+ */
+ if (mux_gpio) {
+ sdata = typec_dp_bridge->sdata;
+ mux_val = gpiod_get_value_cansleep(mux_gpio);
+ typec_dp_bridge->active_port = sdata->ports[mux_val];
+ }
+}
+
static const struct drm_bridge_funcs cros_typec_dp_bridge_funcs = {
.attach = cros_typec_dp_bridge_attach,
.atomic_check = cros_typec_dp_bridge_atomic_check,
@@ -461,6 +486,7 @@ static const struct drm_bridge_funcs cros_typec_dp_bridge_funcs = {
.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
.hpd_enable = cros_typec_dp_bridge_hpd_enable,
.hpd_disable = cros_typec_dp_bridge_hpd_disable,
+ .hpd_notify = cros_typec_dp_bridge_hpd_notify,
};
static int cros_typec_register_dp_bridge(struct cros_typec_switch_data *sdata,
@@ -478,6 +504,10 @@ static int cros_typec_register_dp_bridge(struct cros_typec_switch_data *sdata,
typec_dp_bridge->sdata = sdata;
sdata->typec_dp_bridge = typec_dp_bridge;
+ typec_dp_bridge->mux_gpio = devm_gpiod_get_optional(dev, "mux", 0);
+ if (IS_ERR(typec_dp_bridge->mux_gpio))
+ return PTR_ERR(typec_dp_bridge->mux_gpio);
+
num_lanes = fwnode_property_count_u32(fwnode, "data-lanes");
if (num_lanes < 0)
num_lanes = 4;
@@ -488,7 +518,8 @@ static int cros_typec_register_dp_bridge(struct cros_typec_switch_data *sdata,
bridge->funcs = &cros_typec_dp_bridge_funcs;
bridge->of_node = dev->of_node;
bridge->type = DRM_MODE_CONNECTOR_DisplayPort;
- bridge->ops |= DRM_BRIDGE_OP_HPD;
+ if (!fwnode_property_present(dev_fwnode(dev), "no-hpd"))
+ bridge->ops |= DRM_BRIDGE_OP_HPD;
return devm_drm_bridge_add(dev, bridge);
}
--
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