linux-kernel - Re: [PATCH v4 1/2] drm/bridge: dumb-vga-dac: Support a VDD regulator supply

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Message-ID: <973dddaf-334f-de71-e9bc-4f25e55f1632@codeaurora.org>
Date:   Thu, 17 Nov 2016 14:47:11 +0530
From:   Archit Taneja <architt@...eaurora.org>
To:     Chen-Yu Tsai <wens@...e.org>
Cc:     Maxime Ripard <maxime.ripard@...e-electrons.com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH v4 1/2] drm/bridge: dumb-vga-dac: Support a VDD regulator
 supply



On 11/17/2016 01:25 PM, Chen-Yu Tsai wrote:
> On Thu, Nov 17, 2016 at 3:48 PM, Archit Taneja <architt@...eaurora.org> wrote:
>> Hi,
>>
>> Thanks for the patch.
>>
>>
>> On 11/16/2016 09:12 PM, Chen-Yu Tsai wrote:
>>>
>>> Some dumb VGA DACs are active components which require external power.
>>> Add support for specifying a regulator as its power supply.
>>>
>>> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
>>> Acked-by: Rob Herring <robh@...nel.org>
>>> ---
>>>  .../bindings/display/bridge/dumb-vga-dac.txt       |  2 ++
>>>  drivers/gpu/drm/bridge/dumb-vga-dac.c              | 35
>>> ++++++++++++++++++++++
>>>  2 files changed, 37 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..164cbb15f04c 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:
>>> +- vdd-supply: Power supply for DAC
>>>
>>>  Example
>>>  -------
>>> diff --git a/drivers/gpu/drm/bridge/dumb-vga-dac.c
>>> b/drivers/gpu/drm/bridge/dumb-vga-dac.c
>>> index afec232185a7..15b549f94307 100644
>>> --- a/drivers/gpu/drm/bridge/dumb-vga-dac.c
>>> +++ b/drivers/gpu/drm/bridge/dumb-vga-dac.c
>>> @@ -12,6 +12,7 @@
>>>
>>>  #include <linux/module.h>
>>>  #include <linux/of_graph.h>
>>> +#include <linux/regulator/consumer.h>
>>>
>>>  #include <drm/drmP.h>
>>>  #include <drm/drm_atomic_helper.h>
>>> @@ -23,6 +24,7 @@ struct dumb_vga {
>>>         struct drm_connector    connector;
>>>
>>>         struct i2c_adapter      *ddc;
>>> +       struct regulator        *vdd;
>>>  };
>>>
>>>  static inline struct dumb_vga *
>>> @@ -124,8 +126,32 @@ 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);
>>> +       int ret = 0;
>>> +
>>> +       if (vga->vdd)
>>> +               ret = regulator_enable(vga->vdd);
>>> +
>>> +       if (ret) {
>>> +               DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
>>> +               return;
>>
>>
>> We don't need this return for now. If you're okay with it, can I fix this
>> and queue to misc?
>
> Yes, please!

pushed to drm-misc.

Thanks,
Archit

>
> Thanks
> ChenYu
>
>>
>> Thanks,
>> Archit
>>
>>
>>> +       }
>>> +}
>>> +
>>> +static void dumb_vga_disable(struct drm_bridge *bridge)
>>> +{
>>> +       struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
>>> +
>>> +       if (vga->vdd)
>>> +               regulator_disable(vga->vdd);
>>> +}
>>> +
>>>  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 +195,15 @@ static int dumb_vga_probe(struct platform_device
>>> *pdev)
>>>                 return -ENOMEM;
>>>         platform_set_drvdata(pdev, vga);
>>>
>>> +       vga->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
>>> +       if (IS_ERR(vga->vdd)) {
>>> +               ret = PTR_ERR(vga->vdd);
>>> +               if (ret == -EPROBE_DEFER)
>>> +                       return -EPROBE_DEFER;
>>> +               vga->vdd = NULL;
>>> +               dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", 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

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project