[RFC PATCH v2 00/13] arm/tegra: Initialize GPIO & pinmux from DT

Stephen Warren
2011-08-15T20:28:33Z

v2:
* Enhanced pinmux code to handle "drive pingroups" as well as "mux
pingroups". This altered the pinmux binding a little; shifting each
type of pingroup into a sub-node in the pinmux node.
* Enumerate pingroups by enumerating DT child nodes, and mapping them to
pingroups, rather than the other way around. Hence also removed
modifications to <linux/of.h> and drivers/of/base.c.
* Included documentation of the bindings.
* Represent pingroup names and function names, as lower case in DT.
* Used a better name for GPIO binding GPIO list.
* Switched to boolean properties for pinmux pull-up/down.
* s/dev_err/dev_dbg/ in DT parsing debug code.
* Various minor cleanups (e.g. typos, white-space).

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.

Thanks for reading!

Stephen Warren (13):
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
docs/dt: Document nvidia,tegra20-gpio's nvidia,enabled-gpios property
arm/dt: Tegra: Add nvidia,gpios property to GPIO controller
docs/dt: Document nvidia,tegra20-pinmux binding
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

.../devicetree/bindings/gpio/gpio_nvidia.txt | 20 +
.../devicetree/bindings/pinmux/pinmux_nvidia.txt | 294 ++++++++++++
arch/arm/boot/dts/tegra-harmony.dts | 483 ++++++++++++++++++++
arch/arm/boot/dts/tegra-seaboard.dts | 421 +++++++++++++++++
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 | 269 +++++++++++
drivers/gpio/gpio-tegra.c | 57 ++-
15 files changed, 1582 insertions(+), 24 deletions(-)
create mode 100644 Documentation/devicetree/bindings/pinmux/pinmux_nvidia.txt