[RFC PATCH 00/12] arm/tegra: Initialize GPIO & pinmux from DT

From: Stephen Warren
Date: Fri Aug 12 2011 - 18:55:31 EST

This patch modifies Tegra's device tree support to remove the dependency
on harmony_pinmux_init(), thus making it completely board-independent.

Some notes:

* This series is built on top of linux-next with a bunch of patches
applied, in particular the removal of irq_to_gpio and custom gpio_to_irq
that I'm in the process of sending to Russell. I haven't yet thought
through how/where to merge this without causing all kinds of conflicts.

* I took care to preserve bisectability of Tegra DT support. However,
linux-next doesn't yet have entirely useful Tegra DT support; some stuff
from Grant's devicetree/next hasn't been pushed into linux-next yet. If
we don't care about bisectability, I can remove a couple commits and
possibly squash some others.

* The approach taken here is to have a custom semantic SoC-specific
binding for each the gpio and pinmux drivers. Other alternatives
suggested included:

1) A generic "list of register writes" to be performed at boot. This has
the advantage of reusability across different SoCs. However, this
approach isn't semantic, and requires detailed knowledge of pinmux
registers and potentially fiddly calculations when constructing the
device tree.

2) The ability to define disabled child nodes of the pinmux controller
that are not processed by tegra_pinmux_probe_dt(). Other devices may
refer to those using phandles, and later enable/disable them, thus
representing dynamic pinmuxing in the device tree. I wasn't convinced
whether we should represent dynamic pinmuxing using phandles.

I discussed in more detail why I prefer the current proposal in various
email threads.

* tegra_pinmux_probe_dt() enumerates all legal pingroup names, and searches
for a pinmux controller subnode of that name, then processes each one
that is found. An alternative that some may prefer would be to enumerate
each child node of the pinmux controller, and have each node contain an
explicit pingroup name property instead. Does anyone have any preference
here? I suppose the latter option would obviate the need to add

Thanks for reading!

Stephen Warren (12):
dt: Add of_find_child_node_by_name()
arm/tegra: Prep boards for gpio/pinmux conversion to pdevs
arm/tegra: Avoid duplicate gpio/pinmux devices with dt
arm/tegra: board-dt: Add AUXDATA for tegra-gpio and tegra-pinmux
arm/dt: Tegra: Add nvidia,gpios property to GPIO controller
arm/dt: Tegra: Add pinmux node
gpio/tegra: Convert to a platform device
gpio/tegra: Add device tree support
arm/tegra: Convert pinmux driver to a platform device
arm/tegra: Add device tree support to pinmux driver
arm/tegra: board-dt: Remove dependency on non-dt pinmux functions
arm/tegra: Remove temporary gpio/pinmux registration workaround

arch/arm/boot/dts/tegra-harmony.dts | 479 ++++++++++++++++++++++++++
arch/arm/boot/dts/tegra-seaboard.dts | 409 ++++++++++++++++++++++
arch/arm/boot/dts/tegra20.dtsi | 5 +
arch/arm/mach-tegra/Makefile | 1 -
arch/arm/mach-tegra/board-dt.c | 12 +-
arch/arm/mach-tegra/board-harmony-pinmux.c | 8 +
arch/arm/mach-tegra/board-paz00-pinmux.c | 8 +
arch/arm/mach-tegra/board-seaboard-pinmux.c | 9 +-
arch/arm/mach-tegra/board-trimslice-pinmux.c | 7 +
arch/arm/mach-tegra/devices.c | 10 +
arch/arm/mach-tegra/devices.h | 2 +
arch/arm/mach-tegra/pinmux.c | 136 ++++++++
drivers/gpio/gpio-tegra.c | 56 +++-
drivers/of/base.c | 18 +
include/linux/of.h | 2 +
15 files changed, 1138 insertions(+), 24 deletions(-)

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