Re: [PATCH] clk: sunxi: Extend the simple gates and handle the Allwinner H3

Hi Jean-Francois,

On Tue, Dec 08, 2015 at 07:42:26AM +0100, Jean-Francois Moine wrote:

On Mon, 7 Dec 2015 08:31:02 -0600
Rob Herring [off-list ref] wrote:

quoted

On Sun, Dec 06, 2015 at 10:04:12AM +0100, Jean-Francois Moine wrote:

quoted

The H3 has a clock gate definition similar to the other Allwinner SoCs,
but with a different parent clock for each single gate.

Adding the names of the parent clocks in both the source and output clocks
permits the use of the simple-gates driver to define the bus gates
of all known Allwinner SoCs.

Signed-off-by: Jean-Francois Moine <redacted>
---
This patch replaces a part of Jens Kuske's patch
	[PATCH v5 1/4] clk: sunxi: Add H3 clocks support
---
 Documentation/devicetree/bindings/clock/sunxi.txt | 25 +++++++++++++++++++++++
 drivers/clk/sunxi/clk-simple-gates.c              | 14 ++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
index 8a47b77..5736e6d 100644
--- a/Documentation/devicetree/bindings/clock/sunxi.txt
+++ b/Documentation/devicetree/bindings/clock/sunxi.txt

@@ -70,6 +70,7 @@ Required properties:
 	"allwinner,sun8i-a23-usb-clk" - for usb gates + resets on A23
 	"allwinner,sun9i-a80-usb-mod-clk" - for usb gates + resets on A80
 	"allwinner,sun9i-a80-usb-phy-clk" - for usb phy gates + resets on A80
+	"allwinner,sunxi-gates-clk" - simple gates
 
 Required properties for all clocks:
 - reg : shall be the control register address for the clock.

@@ -93,6 +94,12 @@ The "allwinner,sun9i-a80-mmc-config-clk" clock also requires:
 - #reset-cells : shall be set to 1
 - resets : shall be the reset control phandle for the mmc block.
 
+The "allwinner,sunxi-gates-clk" clock also requires:
+- clock-names : corresponding names of the parent clocks
+when the output clocks have different parents.
+These names must be 4 characters long and must appear as a prefix in
+the names of the output clocks. See example.
+

I don't think you should be encoding relationships of clocks using the 
name strings. We describe relationships in DT via parent/child or 
phandles.

As you know, in the H3, each of the 49 output clock has one of the 4
main clocks as its source.
There are 3 options for defining the source of each clock:
1- all definitions are in the DT,
2- some definitions are in the DT, some other ones are hard-coded,
3- all definitions are hard-coded.

Look, we all agreed on a solution that raised all objections, but
yours.

I'm going to take Jens patch.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com