Hi,
On 10/20/2016 09:13 AM, Chen-Yu Tsai wrote:
Some rgb-to-vga bridges have an enable GPIO, either directly tied to
an enable pin on the bridge IC, or indirectly controlling a power
switch.
Add support for it.
Does the bridge on your platform have an active/passive DAC, or is it a
smarter encoder chip that is capable of doing more? If so, it might be
good to have a separate DT compatible string to it, like what's done
in the patch titled:
drm: bridge: vga-dac: Add adi,adv7123 compatible string
so that we can switch to a different driver later if needed.
Thanks,
Archit
Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
---
.../bindings/display/bridge/dumb-vga-dac.txt | 2 ++
drivers/gpu/drm/bridge/dumb-vga-dac.c | 28 ++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
index 003bc246a270..d3484822bf77 100644
--- a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
+++ b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt
@@ -16,6 +16,8 @@ graph bindings specified in Documentation/devicetree/bindings/graph.txt.
- Video port 0 for RGB input
- Video port 1 for VGA output
+Optional properties:
+- enable-gpios: GPIO pin to enable or disable the bridge
Example
-------
diff --git a/drivers/gpu/drm/bridge/dumb-vga-dac.c b/drivers/gpu/drm/bridge/dumb-vga-dac.c
index afec232185a7..b487e5e9b56d 100644
--- a/drivers/gpu/drm/bridge/dumb-vga-dac.c
+++ b/drivers/gpu/drm/bridge/dumb-vga-dac.c
@@ -10,6 +10,7 @@
* the License, or (at your option) any later version.
*/
+#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of_graph.h>
@@ -23,6 +24,7 @@ struct dumb_vga {
struct drm_connector connector;
struct i2c_adapter *ddc;
+ struct gpio_desc *enable_gpio;
};
static inline struct dumb_vga *
@@ -124,8 +126,26 @@ static int dumb_vga_attach(struct drm_bridge *bridge)
return 0;
}
+static void dumb_vga_enable(struct drm_bridge *bridge)
+{
+ struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
+
+ if (vga->enable_gpio)
+ gpiod_set_value_cansleep(vga->enable_gpio, 1);
+}
+
+static void dumb_vga_disable(struct drm_bridge *bridge)
+{
+ struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
+
+ if (vga->enable_gpio)
+ gpiod_set_value_cansleep(vga->enable_gpio, 0);
+}
+
static const struct drm_bridge_funcs dumb_vga_bridge_funcs = {
.attach = dumb_vga_attach,
+ .enable = dumb_vga_enable,
+ .disable = dumb_vga_disable,
};
static struct i2c_adapter *dumb_vga_retrieve_ddc(struct device *dev)
@@ -169,6 +189,14 @@ static int dumb_vga_probe(struct platform_device *pdev)
return -ENOMEM;
platform_set_drvdata(pdev, vga);
+ vga->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(vga->enable_gpio)) {
+ ret = PTR_ERR(vga->enable_gpio);
+ dev_err(&pdev->dev, "failed to request GPIO: %d\n", ret);
+ return ret;
+ }
+
vga->ddc = dumb_vga_retrieve_ddc(&pdev->dev);
if (IS_ERR(vga->ddc)) {
if (PTR_ERR(vga->ddc) == -ENODEV) {
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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