drm/bridge: simple-bridge: Add support for enable GPIO

If an enable GPIO is declared in the firmware, assert it when enabling
the bridge and deassert it when disabling it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200226112514.12455-14-laurent.pinchart@ideasonboard.com

diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
index 20866c1..70e6092 100644 (file)
--- a/drivers/gpu/drm/bridge/simple-bridge.c
+++ b/drivers/gpu/drm/bridge/simple-bridge.c
@@ -6,6 +6,7 @@
  * Maxime Ripard <maxime.ripard@free-electrons.com>
  */
 
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_graph.h>
@@ -30,6 +31,7 @@ struct simple_bridge {
 
        struct i2c_adapter      *ddc;
        struct regulator        *vdd;
+       struct gpio_desc        *enable;
 };
 
 static inline struct simple_bridge *
@@ -143,19 +145,23 @@ static int simple_bridge_attach(struct drm_bridge *bridge,
 static void simple_bridge_enable(struct drm_bridge *bridge)
 {
        struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
-       int ret = 0;
+       int ret;
 
-       if (sbridge->vdd)
+       if (sbridge->vdd) {
                ret = regulator_enable(sbridge->vdd);
+               if (ret)
+                       DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
+       }
 
-       if (ret)
-               DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
+       gpiod_set_value_cansleep(sbridge->enable, 1);
 }
 
 static void simple_bridge_disable(struct drm_bridge *bridge)
 {
        struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
 
+       gpiod_set_value_cansleep(sbridge->enable, 0);
+
        if (sbridge->vdd)
                regulator_disable(sbridge->vdd);
 }
@@ -208,6 +214,14 @@ static int simple_bridge_probe(struct platform_device *pdev)
                dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
        }
 
+       sbridge->enable = devm_gpiod_get_optional(&pdev->dev, "enable",
+                                                 GPIOD_OUT_LOW);
+       if (IS_ERR(sbridge->enable)) {
+               if (PTR_ERR(sbridge->enable) != -EPROBE_DEFER)
+                       dev_err(&pdev->dev, "Unable to retrieve enable GPIO\n");
+               return PTR_ERR(sbridge->enable);
+       }
+
        sbridge->ddc = simple_bridge_retrieve_ddc(&pdev->dev);
        if (IS_ERR(sbridge->ddc)) {
                if (PTR_ERR(sbridge->ddc) == -ENODEV) {