Am Samstag, 21. Mai 2016, 11:55:35 schrieb Shawn Lin:

On 2016/5/20 19:20, Heiko Stuebner wrote:

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Hi Shawn,

Am Freitag, 20. Mai 2016, 18:29:06 schrieb Shawn Lin:

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This patch add some required and optional properties for Rockchip
PCIe controller. Also we add a example for how to use it.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

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+- msi-parent: Link to the hardware entity that serves as the Message
+- pinctrl-names : The pin control state names
+- pinctrl-0: The "default" pinctrl state

I'm not sure if pinctrl-properties need to be described when you don't
need special handling in the form of additional pin states. The pcie
part does not do any pin-handling of its own.

We need it in prevention of any firmwares change the default state
of #CLKREQ which is useful for ASPM. Also we have a backup pin for
clkreqn called clkreqnb, which should be taken more consideration since
when refering to any one of these two, pinctrl should configure the
bit[14] of GRF_SOC_CON7 automatically. But it is unfortunately beyound
the implementation of pinctrl-rk3399.

BTW, I don't know if we wanna support this action inside the pinctrl
code?

The TRM says for me for that bit only "pcie_clkreq_sel port control" and 
that naming really suggests that it is a property of the pcie controller, 
not the generic pinctrl. So if this needs to be touched the pcie controller 
needs to do it.

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+- interrupt-map-mask and interrupt-map: standard PCI properties
+- interrupt-controller: identifies the node as an interrupt controller
+
+Optional Property:
+- ep-gpios: contain the entry for pre-reset gpio
+- num-lanes: number of lanes to use
+- assigned-clocks, assigned-clock-parents and assigned-clock-rates:
standard +		   clock bindings. See ../clock/clock-bindings.txt

Again that (assigned-clocks handling) is not actual part of the pci-
controllers actions, but other parts and also described already
elsewhere.

Basically it does. But this is an alternative choice for pcie-phy to
generate the ref_clk. When we want 100MHz src clk for PLL inside the
pcie-phy，we should add them, otherwise it's taken from xin 24MHz.

This is useful for SI testing or some others special cases. So should we
add it as an option and leave a sample here?

What I meant was that while clock handling is important when looking at the 
whole system, the pcie controller itself does only care that it gets a 
clock, but not that much where you get it from.

So while assigned-clocks has its place in the real devicetree, I don't think 
it is an element of the actual pcie-controller binding.


Heiko