Hi Sam,
(stumbled on this accidentally)
On Thu, Aug 2, 2018 at 9:46 PM Sam Ravnborg sam@ravnborg.org wrote:
The pardata supports implement a simple bus for devices that are connected using a parallel bus driven by GPIOs. The is often used in combination with simple displays that is often seen in older embedded designs. There is a demand for this support also in the linux kernel for HW designs that uses these kind of displays.
The pardata bus uses a platfrom_driver that when probed creates devices for all child nodes in the DT, which are then supposed to be handled by pardata_drivers.
Signed-off-by: Sam Ravnborg sam@ravnborg.org
--- /dev/null +++ b/Documentation/driver-api/pardata.rst @@ -0,0 +1,60 @@ +.. SPDX-License-Identifier: GPL-2.0
+========================= +Parallel Data Bus/Drivers +=========================
+Displays may be connected using a simple parallel bus. +This is often seen in embedded systems with a simple MCU, but is also +used in Linux based systems to a small extent.
+The bus looks like this:
+.. code-block:: none
----+| DB0-DB7 or DB4-DB7 +----===/========================| E - enable | D---------------------------- IC | Reset | SP ---------------------------- PU | Read/Write (one or two) | L---------------------------- A| RS - instruction/data | Y----------------------------| +--------+
Oh, cool! Looks like this can be used by the hd44780 driver.
Documentation/devicetree/bindings/auxdisplay/hit,hd44780.txt drivers/auxdisplay/hd44780.c
Gr{oetje,eeting}s,
Geert