drm/bridge: display-connector: add DP support

Add DP support to display-connector driver. The driver will support HPD
via a GPIO and DP PWR.

DP PWR will be enabled at probe, which is not optimal, but I'm not sure
what would be a good place to enable and disable DP PWR. Perhaps
attach/detach, but I don't know if enabling HW is something that attach
is supposed to do.

In any case, I don't think there's much difference in power consumption
between the version in this patch and enabling the regulator later: if
the driver probes, supposedly it will attach very soon afterwards, and
we need to enable the DP PWR as soon as possible.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201130112919.241054-3-tomi.valkeinen@ti.com

diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c
index 4d27857..05eb759 100644 (file)
--- a/drivers/gpu/drm/bridge/display-connector.c
+++ b/drivers/gpu/drm/bridge/display-connector.c
@@ -11,6 +11,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 
 #include <drm/drm_bridge.h>
 #include <drm/drm_edid.h>
@@ -20,6 +21,8 @@ struct display_connector {
 
        struct gpio_desc        *hpd_gpio;
        int                     hpd_irq;
+
+       struct regulator        *dp_pwr;
 };
 
 static inline struct display_connector *
@@ -172,11 +175,12 @@ static int display_connector_probe(struct platform_device *pdev)
        of_property_read_string(pdev->dev.of_node, "label", &label);
 
        /*
-        * Get the HPD GPIO for DVI and HDMI connectors. If the GPIO can provide
+        * Get the HPD GPIO for DVI, HDMI and DP connectors. If the GPIO can provide
         * edge interrupts, register an interrupt handler.
         */
        if (type == DRM_MODE_CONNECTOR_DVII ||
-           type == DRM_MODE_CONNECTOR_HDMIA) {
+           type == DRM_MODE_CONNECTOR_HDMIA ||
+           type == DRM_MODE_CONNECTOR_DisplayPort) {
                conn->hpd_gpio = devm_gpiod_get_optional(&pdev->dev, "hpd",
                                                         GPIOD_IN);
                if (IS_ERR(conn->hpd_gpio)) {
@@ -223,6 +227,38 @@ static int display_connector_probe(struct platform_device *pdev)
                }
        }
 
+       /* Get the DP PWR for DP connector. */
+       if (type == DRM_MODE_CONNECTOR_DisplayPort) {
+               int ret;
+
+               conn->dp_pwr = devm_regulator_get_optional(&pdev->dev, "dp-pwr");
+
+               if (IS_ERR(conn->dp_pwr)) {
+                       ret = PTR_ERR(conn->dp_pwr);
+
+                       switch (ret) {
+                       case -ENODEV:
+                               conn->dp_pwr = NULL;
+                               break;
+
+                       case -EPROBE_DEFER:
+                               return -EPROBE_DEFER;
+
+                       default:
+                               dev_err(&pdev->dev, "failed to get DP PWR regulator: %d\n", ret);
+                               return ret;
+                       }
+               }
+
+               if (conn->dp_pwr) {
+                       ret = regulator_enable(conn->dp_pwr);
+                       if (ret) {
+                               dev_err(&pdev->dev, "failed to enable DP PWR regulator: %d\n", ret);
+                               return ret;
+                       }
+               }
+       }
+
        conn->bridge.funcs = &display_connector_bridge_funcs;
        conn->bridge.of_node = pdev->dev.of_node;
 
@@ -251,6 +287,9 @@ static int display_connector_remove(struct platform_device *pdev)
 {
        struct display_connector *conn = platform_get_drvdata(pdev);
 
+       if (conn->dp_pwr)
+               regulator_disable(conn->dp_pwr);
+
        drm_bridge_remove(&conn->bridge);
 
        if (!IS_ERR(conn->bridge.ddc))
@@ -275,6 +314,9 @@ static const struct of_device_id display_connector_match[] = {
        }, {
                .compatible = "vga-connector",
                .data = (void *)DRM_MODE_CONNECTOR_VGA,
+       }, {
+               .compatible = "dp-connector",
+               .data = (void *)DRM_MODE_CONNECTOR_DisplayPort,
        },
        {},
 };