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Message-ID: <123b8767-7ea4-e6fe-6d47-0f2444a88dd9@baylibre.com>
Date:   Tue, 28 Jun 2022 09:10:48 +0200
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Subject: Re: [PATCH v2] drm/bridge: imx: i.MX8 bridge drivers should depend on
 ARCH_MXC
Content-Language: en-US
To:     Liu Ying <victor.liu@nxp.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Robert Foss <robert.foss@linaro.org>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Marek Vasut <marex@denx.de>
Cc:     dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <42c542b53a1c8027b23a045045fbb7b34479913d.1656072500.git.geert+renesas@glider.be>
 <b625ba83-fee9-b668-09db-976cb3bef3ca@baylibre.com>
 <9f5b511708ca9b30ef101a46a5d1b76f03b2c4fc.camel@nxp.com>
From:   Neil Armstrong <narmstrong@baylibre.com>
Organization: Baylibre
In-Reply-To: <9f5b511708ca9b30ef101a46a5d1b76f03b2c4fc.camel@nxp.com>
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Precedence: bulk

On 28/06/2022 04:31, Liu Ying wrote:
> On Mon, 2022-06-27 at 14:22 +0200, Neil Armstrong wrote:
>> Hi,
> 
> Hi,
> 
>>
>> On 24/06/2022 14:10, Geert Uytterhoeven wrote:
>>> The various Freescale i.MX8 display bridges are only present on
>>> Freescale i.MX8 SoCs.  Hence add a dependency on ARCH_MXC, to
>>> prevent
>>> asking the user about these drivers when configuring a kernel
>>> without
>>> i.MX SoC support.
>>>
>>> Fixes: e60c4354840b2fe8 ("drm/bridge: imx: Add LDB support for
>>> i.MX8qm")
>>> Fixes: 3818715f62b42b5c ("drm/bridge: imx: Add LDB support for
>>> i.MX8qxp")
>>> Fixes: 96988a526c97cfbe ("drm/bridge: imx: Add i.MX8qxp pixel link
>>> to DPI support")
>>> Fixes: 1ec17c26bc06289d ("drm/bridge: imx: Add i.MX8qm/qxp display
>>> pixel link support")
>>> Fixes: 93e163a9e0392aca ("drm/bridge: imx: Add i.MX8qm/qxp pixel
>>> combiner support")
>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
>>> Reviewed-by: Liu Ying <victor.liu@nxp.com>
>>> ---
>>> v2:
>>>     - s/i.MX8MP/i.MX8/,
>>>     - Add Reviewed-by.
>>> ---
>>>    drivers/gpu/drm/bridge/imx/Kconfig | 4 ++++
>>>    1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig
>>> b/drivers/gpu/drm/bridge/imx/Kconfig
>>> index 212a7b0e64fd8b5a..608f47f41bcd1c81 100644
>>> --- a/drivers/gpu/drm/bridge/imx/Kconfig
>>> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
>>> @@ -1,3 +1,5 @@
>>> +if ARCH_MXC || COMPILE_TEST
>>> +
>>>    config DRM_IMX8QM_LDB
>>>    	tristate "Freescale i.MX8QM LVDS display bridge"
>>>    	depends on OF
>>> @@ -41,3 +43,5 @@ config DRM_IMX8QXP_PIXEL_LINK_TO_DPI
>>>    	help
>>>    	  Choose this to enable pixel link to display pixel
>>> interface(PXL2DPI)
>>>    	  found in Freescale i.MX8qxp processor.
>>> +
>>> +endif # ARCH_MXC || COMPILE_TEST
>>
>> I was wondering why those were added in drivers/gpu/drm/bridge/imx
>> since they are specific to NXP SoCs,
>> I think they should be moved in the right drm imx subsystem instead
>> of this change.
> 
> There are 2 directories which contain display controller drivers for
> i.MX SoCs:
> a. drivers/gpu/drm/imx - i.MX51/53/6qdl IPUv3, i.MX8mq DCSS and
>     i.MX8qm/qxp DPU([1], not landed yet)
> b. drivers/gpu/drm/mxsfb - i.MX23/28/6sx/8mq LCDIF and i.MX8mp
>     LCDIFv3([2], not landed yet)
> 
> Bridges added in drivers/gpu/drm/bridge/imx make it possible to share
> bridge drivers across display controllers.  I see chance to use the
> LVDS Display Bridge(LDB) helper(imx-ldb-helper.c) for i.MX6sx LDB.

Thanks for the explanation, LGTM
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>

> 
> [1]
> https://patchwork.kernel.org/project/dri-devel/patch/20220407091156.1211923-6-victor.liu@nxp.com/
> [2]
> https://patchwork.kernel.org/project/dri-devel/patch/20220624180201.150417-2-marex@denx.de/
> 
> Regards,
> Liu Ying
>