linux_dsm_epyc7002/Documentation/fb/metronomefb.txt

			Metronomefb
			-----------
Maintained by Jaya Kumar <jayakumar.lkml.gmail.com>
Last revised: Nov 20, 2007

Metronomefb is a driver for the Metronome display controller. The controller
is from E-Ink Corporation. It is intended to be used to drive the E-Ink
Vizplex display media. E-Ink hosts some details of this controller and the
display media here http://www.e-ink.com/products/matrix/metronome.html .

Metronome is interfaced to the host CPU through the AMLCD interface. The
host CPU generates the control information and the image in a framebuffer
which is then delivered to the AMLCD interface by a host specific method.
Currently, that's implemented for the PXA's LCDC controller. The display and
error status are each pulled through individual GPIOs.

Metronomefb was written for the PXA255/gumstix/lyre combination and
therefore currently has board set specific code in it. If other boards based on
other architectures are available, then the host specific code can be separated
and abstracted out.

Metronomefb requires waveform information which is delivered via the AMLCD
interface to the metronome controller. The waveform information is expected to
be delivered from userspace via the firmware class interface. The waveform file
can be compressed as long as your udev or hotplug script is aware of the need
to uncompress it before delivering it. metronomefb will ask for waveform.wbf
which would typically go into /lib/firmware/waveform.wbf depending on your
udev/hotplug setup. I have only tested with a single waveform file which was
originally labeled 23P01201_60_WT0107_MTC. I do not know what it stands for.
Caution should be exercised when manipulating the waveform as there may be
a possibility that it could have some permanent effects on the display media.
I neither have access to nor know exactly what the waveform does in terms of
the physical media.

Metronomefb uses the deferred IO interface so that it can provide a memory
mappable frame buffer. It has been tested with tinyx (Xfbdev). It is known
to work at this time with xeyes, xclock, xloadimage, xpdf.
fbdev: defio and Metronomefb Implement support for the E-Ink Metronome controller. It provides an mmapable interface to the controller using defio support. It was tested with a gumstix pxa255 with Vizplex media using Xfbdev and various X clients such as xeyes, xpdf, xloadimage. This patch also fixes the following bug: Defio would cause a hang on write access to the framebuffer as the page fault would be called ad-infinitum. It fixes fb_defio by setting the mapping to be used by page_mkclean. Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 2008-03-20 07:01:10 +07:00			`Metronomefb`
			`-----------`
			`Maintained by Jaya Kumar <jayakumar.lkml.gmail.com>`
			`Last revised: Nov 20, 2007`

			`Metronomefb is a driver for the Metronome display controller. The controller`
			`is from E-Ink Corporation. It is intended to be used to drive the E-Ink`
			`Vizplex display media. E-Ink hosts some details of this controller and the`
			`display media here http://www.e-ink.com/products/matrix/metronome.html .`

			`Metronome is interfaced to the host CPU through the AMLCD interface. The`
			`host CPU generates the control information and the image in a framebuffer`
			`which is then delivered to the AMLCD interface by a host specific method.`
			`Currently, that's implemented for the PXA's LCDC controller. The display and`
			`error status are each pulled through individual GPIOs.`

			`Metronomefb was written for the PXA255/gumstix/lyre combination and`
			`therefore currently has board set specific code in it. If other boards based on`
			`other architectures are available, then the host specific code can be separated`
			`and abstracted out.`

			`Metronomefb requires waveform information which is delivered via the AMLCD`
			`interface to the metronome controller. The waveform information is expected to`
			`be delivered from userspace via the firmware class interface. The waveform file`
			`can be compressed as long as your udev or hotplug script is aware of the need`
			`to uncompress it before delivering it. metronomefb will ask for waveform.wbf`
			`which would typically go into /lib/firmware/waveform.wbf depending on your`
			`udev/hotplug setup. I have only tested with a single waveform file which was`
			`originally labeled 23P01201_60_WT0107_MTC. I do not know what it stands for.`
			`Caution should be exercised when manipulating the waveform as there may be`
			`a possibility that it could have some permanent effects on the display media.`
			`I neither have access to nor know exactly what the waveform does in terms of`
			`the physical media.`

			`Metronomefb uses the deferred IO interface so that it can provide a memory`
			`mappable frame buffer. It has been tested with tinyx (Xfbdev). It is known`
			`to work at this time with xeyes, xclock, xloadimage, xpdf.`