[U-Boot] [PATCH 23/23] ARM: tegra: Enable PCIe on Jetson TK1

[Thierry Reding <thierry.reding@gmail.com>]

On Wed, Aug 20, 2014 at 12:51:35PM -0600, Stephen Warren wrote:
> On 08/18/2014 01:16 AM, Thierry Reding wrote:
> >From: Thierry Reding <treding@nvidia.com>
> >
> >The Jetson TK1 has an ethernet NIC connected to the PCIe bus and routes
> >the second root port to a miniPCIe slot. Enable the PCIe controller and
> 
> >diff --git a/arch/arm/dts/tegra124-jetson-tk1.dts b/arch/arm/dts/tegra124-jetson-tk1.dts
> 
> >+	regulators {
> 
> >+		/* Molex power connector */
> >+		vdd_5v0_sata: regulator at 13 {
> ...
> >+		vdd_12v0_sata: regulator at 14 {
> 
> Those two aren't in the kernel DT yet. I'll assume they match what's been
> proposed for the SATA patches:-)
> 
> >diff --git a/board/nvidia/jetson-tk1/jetson-tk1.c b/board/nvidia/jetson-tk1/jetson-tk1.c
> 
> A lot of the AS3722 code here duplicates what's in
> board/nvidia/venice2/as3722_init.[ch]. It'd be good to put it all in one
> place. Personally I'd be OK with putting it into the existing Venice2 code,
> but I suppose as Simon mentioned, a "real" AS3722 driver in
> drivers/power/pmic would be a good idea.

Unfortunately turning this into a real driver for AS3722 makes it
impossible (or at least too difficult) to unify with the code in
venice2/as3722_init.ch. The issue is that the new driver relies on
infrastructure (I2C, FDT) that's not available in SPL (where this
code is run). I tried extending the SPL with I2C and power drivers
support so that I could use the driver here as well, but that keeps
failing at various points, so I preferred having a proper driver for
full U-Boot and kept the low-level code for CPU power rail setup as is.

Note that I haven't turned the AS3722 support into a "PMIC" driver,
because the framework for that seems to be unusable. It doesn't seem to
abstract away driver-specifics at all but rather provides a way to
access registers in a uniform way (sort of what regmap does in Linux).
Using that framework would therefore require knowledge about the exact
register accesses within drivers and therefore wouldn't be an
improvement over the current situation.

Thierry
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