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Message-ID: <660471a0-480b-241f-8880-8b56aed3e64b@gmail.com>
Date: Wed, 18 Jul 2018 09:28:25 +0200
From: Matthias Brugger <matthias.bgg@...il.com>
To: Sean Wang <sean.wang@...iatek.com>, matthias.bgg@...nel.org
Cc: ulrich.hecht+renesas@...il.com, laurent.pinchart@...asonboard.com,
ck.hu@...iatek.com, p.zabel@...gutronix.de, airlied@...ux.ie,
robh+dt@...nel.org, mark.rutland@....com, mturquette@...libre.com,
sboyd@...eaurora.org, lee.jones@...aro.org, davem@...emloft.net,
gregkh@...uxfoundation.org, mchehab@...nel.org,
rdunlap@...radead.org, pi-cheng.chen@...aro.org,
linux-clk@...r.kernel.org, linux@...linux.org.uk,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org,
Matthias Brugger <mbrugger@...e.com>
Subject: Re: [resend PATCH v4 4/5] drm/mediatek: Add support for mmsys through
a pdev
On 18/07/18 09:27, Matthias Brugger wrote:
> Hi Sean,
>
> On 18/07/18 04:57, Sean Wang wrote:
>> On Wed, 2018-07-18 at 00:03 +0200, matthias.bgg@...nel.org wrote:
>>> From: Matthias Brugger <mbrugger@...e.com>
>>>
>>> The MMSYS subsystem includes clocks and drm components.
>>> This patch adds an initailization path through a platform device
>>> for the clock part, so that both drivers get probed from the same
>>> device tree compatible.
>>>
>>
>> Sorry for that I should have a response earlier for the series.
>>
>> Some points I felt they're not exactly right and should be fixed up
>> before we're moving on
>>
>> Currently, drm driver have a wrong reference to the dt-binding,
>> "mediatek,mt2701-mmsys" or "mediatek,mt8173-mmsys", they should be all
>> for the subsystem exporting clock and reset line such common resource to
>> its sub-devices. Every subsystem has a similar shape. I hope mmsys
>> shouldn't be an exception.
>
> I'm not sure if I understand what you mean. You proposed to use a platform
> device [1] and now you say we should change the DTS?
>
> What do you mean by "drm driver has a wrong reference to the dt-binding"? How
> would you want to name it and most important, what would be your approach to
> have backwards compatibility to older device tree bindings?
>
I forgot the reference:
[1] https://patchwork.kernel.org/patch/10367797/
>>
>> DRM device needs to have its own dt-binding show how connections between
>> DRM components being made and its node should be put under mmsys node.
>>> In this way, it becomes easy to see how the topology of the subsystem is
>> and grows, like a tree "device tree", instead of hiding the details in
>> the implementation.
>>
>> The similar example we already did for audsys on mt2701 and mt7623 as
>> below
>>
>> audsys: clock-controller@...20000 {
>> compatible = "mediatek,mt7623-audsys",
>> "mediatek,mt2701-audsys",
>> "syscon";
>> ...
>>
>> afe: audio-controller {
>> compatible = "mediatek,mt7623-audio",
>> "mediatek,mt2701-audio";
>>
>> ...
>> };
>> };
>>
>
> I think this approach is not working as, due to backwards compatibility, we have
> to make sure that the DRM driver gets probed with the mmsys binding.
>
> Regards,
> Matthias
>
>>
>> Sean
>>
>>
>>> Signed-off-by: Matthias Brugger <mbrugger@...e.com>
>>> ---
>>> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 18 ++++++++++++++++++
>>> drivers/gpu/drm/mediatek/mtk_drm_drv.h | 2 ++
>>> 2 files changed, 20 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>>> index dd249cf5121e..c946aea722e5 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
>>> @@ -173,6 +173,7 @@ static const struct mtk_mmsys_driver_data mt2701_mmsys_driver_data = {
>>> .ext_path = mt2701_mtk_ddp_ext,
>>> .ext_len = ARRAY_SIZE(mt2701_mtk_ddp_ext),
>>> .shadow_register = true,
>>> + .clk_drv_name = "clk-mt2701-mm",
>>> };
>>>
>>> static const struct mtk_mmsys_driver_data mt8173_mmsys_driver_data = {
>>> @@ -180,6 +181,7 @@ static const struct mtk_mmsys_driver_data mt8173_mmsys_driver_data = {
>>> .main_len = ARRAY_SIZE(mt8173_mtk_ddp_main),
>>> .ext_path = mt8173_mtk_ddp_ext,
>>> .ext_len = ARRAY_SIZE(mt8173_mtk_ddp_ext),
>>> + .clk_drv_name = "clk-mt8173-mm",
>>> };
>>>
>>> static int mtk_drm_kms_init(struct drm_device *drm)
>>> @@ -411,6 +413,19 @@ static int mtk_drm_probe(struct platform_device *pdev)
>>> if (IS_ERR(private->config_regs))
>>> return PTR_ERR(private->config_regs);
>>>
>>> + if (private->data->clk_drv_name) {
>>> + private->clk_dev = platform_device_register_data(dev,
>>> + private->data->clk_drv_name, -1,
>>> + NULL, 0);
>>> +
>>> + if (IS_ERR(private->clk_dev)) {
>>> + pr_err("failed to register %s platform device\n",
>>> + private->data->clk_drv_name);
>>> +
>>> + return PTR_ERR(private->clk_dev);
>>> + }
>>> + }
>>> +
>>> /* Iterate over sibling DISP function blocks */
>>> for_each_child_of_node(dev->of_node->parent, node) {
>>> const struct of_device_id *of_id;
>>> @@ -515,6 +530,9 @@ static int mtk_drm_remove(struct platform_device *pdev)
>>> for (i = 0; i < DDP_COMPONENT_ID_MAX; i++)
>>> of_node_put(private->comp_node[i]);
>>>
>>> + if (private->clk_dev)
>>> + platform_device_unregister(private->clk_dev);
>>> +
>>> return 0;
>>> }
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
>>> index 86cec19193c4..200eee5de419 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
>>> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
>>> @@ -34,11 +34,13 @@ struct mtk_mmsys_driver_data {
>>> const enum mtk_ddp_comp_id *ext_path;
>>> unsigned int ext_len;
>>> bool shadow_register;
>>> + const char *clk_drv_name;
>>> };
>>>
>>> struct mtk_drm_private {
>>> struct drm_device *drm;
>>> struct device *dma_dev;
>>> + struct platform_device *clk_dev;
>>>
>>> unsigned int num_pipes;
>>>
>>
>>
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