Re: [PATCH 3/5] drm: convert drivers to use of_graph_get_remote_node

[Rob Herring]

On Mon, Feb 6, 2017 at 4:52 AM, Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote:
> On Fri, 2017-02-03 at 21:36 -0600, Rob Herring wrote:
>> Convert drivers to use the new of_graph_get_remote_node() helper
>> instead of parsing the endpoint node and then getting the remote device
>> node. Now drivers can just specify the device node and which
>> port/endpoint and get back the connected remote device node. The details
>> of the graph binding are nicely abstracted into the core OF graph code.
>>
>> This changes some error messages to debug messages (in the graph core).
>> Graph connections are often "no connects" depending on the particular
>> board, so we want to avoid spurious messages. Plus the kernel is not a
>> DT validator.
>>
>> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
>> ---
>>  drivers/gpu/drm/arm/hdlcd_drv.c                 | 22 ++-------
>>  drivers/gpu/drm/arm/malidp_drv.c                | 29 ++---------
>>  drivers/gpu/drm/bridge/adv7511/adv7533.c        | 12 +----
>>  drivers/gpu/drm/bridge/dumb-vga-dac.c           | 15 ++----
>>  drivers/gpu/drm/bridge/ti-tfp410.c              | 15 ++----
>>  drivers/gpu/drm/exynos/exynos_drm_dpi.c         | 16 +-----
>>  drivers/gpu/drm/exynos/exynos_drm_dsi.c         | 13 ++---
>>  drivers/gpu/drm/exynos/exynos_drm_mic.c         | 27 +---------
>>  drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c    | 26 ++--------
>>  drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 30 +----------
>>  drivers/gpu/drm/mediatek/mtk_dpi.c              | 12 ++---
>>  drivers/gpu/drm/mediatek/mtk_hdmi.c             | 26 ++--------
>>  drivers/gpu/drm/meson/meson_drv.c               | 12 ++---
>>  drivers/gpu/drm/meson/meson_venc_cvbs.c         | 19 ++-----
>>  drivers/gpu/drm/msm/dsi/dsi_host.c              |  3 +-
>>  drivers/gpu/drm/msm/mdp/mdp4/mdp4_kms.c         | 28 +----------
>>  drivers/gpu/drm/rockchip/rockchip_drm_drv.c     | 18 +++----
>>  drivers/gpu/drm/tilcdc/tilcdc_crtc.c            | 11 +----
>>  drivers/gpu/drm/tilcdc/tilcdc_external.c        | 66 +++----------------------
>>  drivers/gpu/drm/vc4/vc4_dpi.c                   | 15 ++----
>>  20 files changed, 64 insertions(+), 351 deletions(-)
>>
> [...]
>> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
>> index 90fb831ef031..dbd554c09a39 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
>> @@ -661,7 +661,7 @@ static int mtk_dpi_probe(struct platform_device *pdev)
>>       struct device *dev = &pdev->dev;
>>       struct mtk_dpi *dpi;
>>       struct resource *mem;
>> -     struct device_node *ep, *bridge_node = NULL;
>> +     struct device_node *bridge_node;
>>       int comp_id;
>>       int ret;
>>
>> @@ -706,15 +706,9 @@ static int mtk_dpi_probe(struct platform_device *pdev)
>>               return -EINVAL;
>>       }
>>
>> -     ep = of_graph_get_next_endpoint(dev->of_node, NULL);
>> -     if (ep) {
>> -             bridge_node = of_graph_get_remote_port_parent(ep);
>> -             of_node_put(ep);
>> -     }
>> -     if (!bridge_node) {
>> -             dev_err(dev, "Failed to find bridge node\n");
>> +     bridge_node = of_graph_get_remote_node(dev->of_node, 0, 0);
>
> Note that before this change, of_graph_get_next_endpoint would just
> choose the first port/endpoint without restrictions to their reg
> properties, whereas the new code requires reg to be either not set or
> set to zero.
> As the former is the case for the mt8173 dpi->hdmi link, which is the
> only use of this driver, this should be fine.

Yes, that is on purpose. A given node should have known port numbering
and know what type of port each port is. The binding doc should
outline the ports and endpoints.

>
> [...]
>> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
>> index 0e8c4d9af340..f14e472812ce 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
>> @@ -1433,7 +1433,7 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi,
>>  {
>>       struct device *dev = &pdev->dev;
>>       struct device_node *np = dev->of_node;
>> -     struct device_node *cec_np, *port, *ep, *remote, *i2c_np;
>> +     struct device_node *cec_np, *remote, *i2c_np;
>>       struct platform_device *cec_pdev;
>>       struct regmap *regmap;
>>       struct resource *mem;
>> @@ -1485,29 +1485,9 @@ static int mtk_hdmi_dt_parse_pdata(struct mtk_hdmi *hdmi,
>>       if (IS_ERR(hdmi->regs))
>>               return PTR_ERR(hdmi->regs);
>>
>> -     port = of_graph_get_port_by_id(np, 1);
>> -     if (!port) {
>> -             dev_err(dev, "Missing output port node\n");
>> +     remote = of_graph_get_remote_node(np, 1, 0);
>> +     if (!remote)
>>               return -EINVAL;
>> -     }
>> -
>> -     ep = of_get_child_by_name(port, "endpoint");
>> -     if (!ep) {
>> -             dev_err(dev, "Missing endpoint node in port %s\n",
>> -                     port->full_name);
>> -             of_node_put(port);
>> -             return -EINVAL;
>> -     }
>> -     of_node_put(port);
>> -
>> -     remote = of_graph_get_remote_port_parent(ep);
>> -     if (!remote) {
>> -             dev_err(dev, "Missing connector/bridge node for endpoint %s\n",
>> -                     ep->full_name);
>> -             of_node_put(ep);
>> -             return -EINVAL;
>> -     }
>> -     of_node_put(ep);
>
> Same as above. TMDS links reasonably have only one endpoint in the
> source port, and the mt8173-evb DT has no reg property set.
>
> Acked-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> for the mediatek changes.

Thanks.

Rob