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 at csie.org> > --- > .../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