linux-kernel - Re: [PATCH v1 1/4] fbtft: Unorphan the driver

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Date:   Wed, 26 Jan 2022 16:08:32 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Javier Martinez Canillas <javierm@...hat.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andy@...nel.org>, linux-fbdev@...r.kernel.org,
        Michael Hennerich <michael.hennerich@...log.com>,
        Helge Deller <deller@....de>, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        Phillip Potter <phil@...lpotter.co.uk>,
        Carlis <zhangxuezhi1@...ong.com>,
        Lee Jones <lee.jones@...aro.org>,
        Heiner Kallweit <hkallweit1@...il.com>
Subject: Re: [PATCH v1 1/4] fbtft: Unorphan the driver

On Wed, Jan 26, 2022 at 02:46:08PM +0100, Javier Martinez Canillas wrote:
> On 1/26/22 14:12, Andy Shevchenko wrote:
> > On Wed, Jan 26, 2022 at 12:26:36PM +0100, Greg Kroah-Hartman wrote:
> >> On Wed, Jan 26, 2022 at 12:17:08PM +0100, Helge Deller wrote:
> >>> On 1/26/22 11:31, Daniel Vetter wrote:
> > 
> > ...
> > 
> >>> You are describing a transitioning over to DRM - which is Ok.
> >>> But on that way there is no need to ignore, deny or even kill usage scenarios
> >>> which are different compared to your usage scenarios (e.g. embedded devices,
> >>> old platforms, slow devices, slow busses, no 3D hardware features,
> >>> low-color devices, ...).
> >>
> >> All of those should be handled by the drm layer, as Daniel keeps
> >> pointing out.  If not, then the tinydrm layer needs to be enhanced to do
> >> so.
> >>
> >> Anyone have a pointer to hardware I can buy that is one of these fbtft
> >> drivers that I could do a port to drm to see just how much work is
> >> really needed here?
> > 
> > I have bought myself (for other purposes, I mean not to convert the driver(s))
> > SSD1306 based display (SPI), SSD1331 (SPI), HX88347d (parallel).
> >
> 
> I've just bought a SSD1306 (I2C) based one and will attempt to write a DRM
> driver using drivers/staging/fbtft/fb_ssd1306.c as a reference.

You should take ssd1307fb.c instead. And basically create a MIPI based driver
for I2C. Then we won't go same road again for other similar devices.

> I didn't find one with a SPI interface but we can later add a transport for
> that if I succeed.

-- 
With Best Regards,
Andy Shevchenko