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Message-ID: <50c93f6d-c546-1479-62c1-adc0b40d5dab@gmail.com>
Date: Wed, 18 Jul 2018 09:27:48 +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
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?
>
> 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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