Hi Rob,
Quick question below based on some discussion on the implementation
details of the PRM support.
On 28/08/2019 10:19, Tero Kristo wrote:
Add new binding for OMAP PRM (Power and Reset Manager) instances. Each
of these will act as a power domain controller and potentially as a reset
provider.
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
.../devicetree/bindings/arm/omap/prm-inst.txt | 31 +++++++++++++++++++
1 file changed, 31 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/omap/prm-inst.txt
diff --git a/Documentation/devicetree/bindings/arm/omap/prm-inst.txt b/Documentation/devicetree/bindings/arm/omap/prm-inst.txt
new file mode 100644
index 000000000000..7c7527c37734
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/omap/prm-inst.txt
@@ -0,0 +1,31 @@
+OMAP PRM instance bindings
+
+Power and Reset Manager is an IP block on OMAP family of devices which
+handle the power domains and their current state, and provide reset
+handling for the domains and/or separate IP blocks under the power domain
+hierarchy.
+
+Required properties:
+- compatible: Must be one of:
+ "ti,am3-prm-inst"
+ "ti,am4-prm-inst"
+ "ti,omap4-prm-inst"
+ "ti,omap5-prm-inst"
+ "ti,dra7-prm-inst"
Each of these bindings describes multiple PRM instances, like
ti,dra7-prm-inst maps eventually into 21 different PRM instances. I end
up matching these in the kernel based on base address to map additional
details, like support for reset handling, supported reset bits, etc.
What is your take on this, should I just provide individual compatible
strings for these all, the total amount of them would end up being like
70+, or keep them like this? I find it rather cumbersome if I would have
to deal with 70+ different compatibles... Also, I would need to keep
updating the bindings doc once I add new instances on the supported list.
-Tero
+- reg: Contains PRM instance register address range
+ (base address and length)
+
+Optional properties:
+- #reset-cells: Should be 1 if the PRM instance in question supports resets.
+- clocks: Associated clocks for the reset signals if any. Certain reset
+ signals can't be toggled properly without functional clock
+ being active for them.
+
+Example:
+
+prm_dsp2: prm@1b00 {
+ compatible = "ti,dra7-prm-inst";
+ reg = <0x1b00 0x40>;
+ #reset-cells = <1>;
+ clocks = <&dsp2_clkctrl DRA7_DSP2_MMU0_DSP2_CLKCTRL 0>;
+};
--
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