Re: [PATCH v2 1/2] dt-bindings: cpufreq: Introduce QCOM CPUFREQ FW bindings

From: Taniya Das
Date: Thu May 24 2018 - 00:53:18 EST




On 5/23/2018 8:43 PM, Sudeep Holla wrote:


On 19/05/18 18:34, Taniya Das wrote:
Add QCOM cpufreq firmware device bindings for Qualcomm Technology Inc's
SoCs. This is required for managing the cpu frequency transitions which are
controlled by firmware.

Signed-off-by: Taniya Das <tdas@xxxxxxxxxxxxxx>
---
.../bindings/cpufreq/cpufreq-qcom-fw.txt | 68 ++++++++++++++++++++++
1 file changed, 68 insertions(+)
create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-fw.txt

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-fw.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-fw.txt
new file mode 100644
index 0000000..bc912f4
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-qcom-fw.txt
@@ -0,0 +1,68 @@
+Qualcomm Technologies, Inc. CPUFREQ Bindings
+
+CPUFREQ FW is a hardware engine used by some Qualcomm Technologies, Inc. (QTI)
+SoCs to manage frequency in hardware. It is capable of controlling frequency
+for multiple clusters.
+
+Properties:
+- compatible
+ Usage: required
+ Value type: <string>
+ Definition: must be "qcom,cpufreq-fw".
+

If the firmware is referred with some other name, better to use that
than cpufreq
+Note that #address-cells, #size-cells, and ranges shall be present to ensure
+the cpufreq can address a freq-domain registers.
+
+A freq-domain sub-node would be defined for the cpus with the following
+properties:
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be "cpufreq".
+
+- reg
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: Addresses and sizes for the memory of the perf_base
+ , lut_base and en_base.

Can you explicitly define each one of them ? Either here or in reg-names.


Sure will define each of them in the next series.

+- reg-names
+ Usage: required
+ Value type: <stringlist>
+ Definition: Address names. Must be "perf_base", "lut_base",
+ "en_base".
+ Must be specified in the same order as the
+ corresponding addresses are specified in the reg
+ property.
+
+- qcom,cpulist
+ Usage: required
+ Value type: <phandles of CPU>
+ Definition: List of related cpu handles which are under a cluster.
+

As already mentioned by Rob and Viresh, better to align with OPP style
to avoid phandle list of CPUs.


I have put down an example device tree node for Rob & Viresh to review.

Also I see similar bindings for devfreq, can't they be aligned ?
E.g. lut_base here while it's ftbl_base in devfreq.


It is actually the look up table, thus was the name given as "lut". Will check with Saravana for devfreq and align accordingly.


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