Re: [PATCH 1/3] mfd: devicetree: bindings: Add Qualcomm RPM DT binding

From: Srinivas Kandagatla
Date: Thu May 29 2014 - 12:19:47 EST


Hi Bjorn,

On 27/05/14 18:28, Bjorn Andersson wrote:
Add binding for the Qualcomm Resource Power Manager (RPM) found in 8660, 8960
and 8064 based devices. The binding currently describes the rpm itself and the
regulator subnodes.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/mfd/qcom,rpm.txt | 284 +++++++++++++++++++++
include/dt-bindings/mfd/qcom_rpm.h | 142 +++++++++++
2 files changed, 426 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mfd/qcom,rpm.txt
create mode 100644 include/dt-bindings/mfd/qcom_rpm.h

diff --git a/Documentation/devicetree/bindings/mfd/qcom,rpm.txt b/Documentation/devicetree/bindings/mfd/qcom,rpm.txt
new file mode 100644
index 0000000..3908a5d
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/qcom,rpm.txt
@@ -0,0 +1,284 @@
+Qualcomm Resource Power Manager (RPM)
+
+This driver is used to interface with the Resource Power Manager (RPM) found in
+various Qualcomm platforms. The RPM allows each component in the system to vote
+for state of the system resources, such as clocks, regulators and bus
+frequencies.
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be one of:
+ "qcom,rpm-apq8064"
+ "qcom,rpm-msm8660"
+ "qcom,rpm-msm8960"
+
+- reg:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: two entries specifying the RPM's message ram and ipc register
+
+- reg-names:
+ Usage: required
+ Value type: <string-array>
+ Definition: must contain the following, in order:
+ "msg_ram"
+ "ipc"

+1 for kumar's comment.

cant enforce the order here. should fix it in the driver.

+
+- interrupts:
+ Usage: required
+ Value type: <prop-encoded-array>
+ Definition: three entries specifying the RPM's:
+ 1. acknowledgement interrupt
+ 2. error interrupt
+ 3. wakeup interrupt
+
+- interrupt-names:
+ Usage: required
+ Value type: <string-array>
+ Definition: must be the three strings "ack", "err" and "wakeup", in order
+
+- #address-cells:
+ Usage: required
+ Value type: <u32>
+ Definition: must be 1
+
+- #size-cells:
+ Usage: required
+ Value type: <u32>
+ Definition: must be 0
+
+
+= SUBDEVICES
+
+The RPM exposes resources to its subnodes. The below bindings specify the set
+of valid subnodes that can operate on these resources.

Why should these devices be on sub nodes?

Any reason not to implement it like this,

rpm: rpm@108000 {
compatible = "qcom,rpm-msm8960";
reg = <0x108000 0x1000 0x2011008 0x4>;

interrupts = <0 19 0>, <0 21 0>, <0 22 0>;
interrupt-names = "ack", "err", "wakeup";
};

pm8921_s1: pm8921-s1 {
compatible = "qcom,rpm-pm8921-smps";

regulator-min-microvolt = <1225000>;
regulator-max-microvolt = <1225000>;
regulator-always-on;

qcom,rpm = <&rpm QCOM_RPM_PM8921_S1>;
qcom,switch-mode-frequency = <3200000>;
qcom,hpm-threshold = <100000>;
};

This would simplify the driver code too and handle the interface neatly then depending on device hierarchy.
rpm would be a interface library to the clients. Makes the drivers more independent, and re-usable if we do this way.

??


+
+== Switch-mode Power Supply regulator
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be one of:
+ "qcom,rpm-pm8058-smps"
+ "qcom,rpm-pm8901-ftsmps"
+ "qcom,rpm-pm8921-smps"
+ "qcom,rpm-pm8921-ftsmps"
+
+- reg:
+ Usage: required
+ Value type: <u32>
+ Definition: resource as defined in <dt-bindings/mfd/qcom_rpm.h>
+
+- qcom,switch-mode-frequency:
+ Usage: required
+ Value type: <u32>
+ Definition: Frequency (Hz) of the switch-mode power supply;
+ must be one of:
+ 19200000, 9600000, 6400000, 4800000, 3840000, 3200000,
+ 2740000, 2400000, 2130000, 1920000, 1750000, 1600000,
+ 1480000, 1370000, 1280000, 1200000
+
+- qcom,hpm-threshold:
+ Usage: optional
+ Value type: <u32>
+ Definition: indicates the breaking point at which the regulator should
+ switch to high power mode
+
+- qcom,load-bias:
+ Usage: optional
+ Value type: <u32>
+ Definition: specifies a base load on the specific regulator
+
+- qcom,boot-load:
+ Usage: optional
+ Value type: <u32>
+ Definition: specifies the configured load on boot for the specific
+ regulator
+

[...
+- qcom,force-mode-none:
+ Usage: optional (default if no other qcom,force-mode is specified)
+ Value type: <empty>
+ Defintion: indicates that the regulator should not be forced to any
+ particular mode
+
+- qcom,force-mode-lpm:
+ Usage: optional
+ Value type: <empty>
+ Definition: indicates that the regulator should be forced to operate in
+ low-power-mode
+
+- qcom,force-mode-auto:
+ Usage: optional (only available for 8960/8064)
+ Value type: <empty>
+ Definition: indicates that the regulator should be automatically pick
+ operating mode
+
+- qcom,force-mode-hpm:
+ Usage: optional (only available for 8960/8064)
+ Value type: <empty>
+ Definition: indicates that the regulator should be forced to operate in
+ high-power-mode
+
+- qcom,force-mode-bypass: (only for 8960/8064)
+ Usage: optional (only available for 8960/8064)
+ Value type: <empty>
+ Definition: indicates that the regulator should be forced to operate in
+ bypass mode
+
...]

Probably qcom,force-mode:
Usage: optional.
Value type: <string>
Definition: must be one of:
"none"
"lpm"
"auto"
"hpm"
"bypass"

Makes it much simpler, as they seems to be mutually exclusive. simillar comments apply to other bindings too.


[...
+- qcom,power-mode-hysteretic:
+ Usage: optional
+ Value type: <empty>
+ Definition: indicates that the power supply should operate in hysteretic
+ mode (defaults to qcom,power-mode-pwm if not specified)
+
+- qcom,power-mode-pwm:
+ Usage: optional
+ Value type: <empty>
+ Definition: indicates that the power supply should operate in pwm mode
+
...]

Probably qcom,power-mode:
Usage: optional.
Value type: <string>
Definition: must be one of:
"pwm"
"hysteretic"


Makes it much simpler, as they seems to be mutually exclusive. simillar comments apply to other bindings too.




Thanks,
srini
+Standard regulator bindings are used inside switch mode power supply subnodes.
+Check Documentation/devicetree/bindings/regulator/regulator.txt for more
+details.
+
+== Low-dropout regulator
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be one of:
+ "qcom,rpm-pm8058-pldo"
+ "qcom,rpm-pm8058-nldo"
+ "qcom,rpm-pm8901-pldo"
+ "qcom,rpm-pm8901-nldo"
+ "qcom,rpm-pm8921-pldo"
+ "qcom,rpm-pm8921-nldo"
+ "qcom,rpm-pm8921-nldo1200"
+
+- reg:
+ Usage: required
+ Value type: <u32>
+ Definition: resource as defined in <dt-bindings/mfd/qcom_rpm.h>
+
+- qcom,hpm-threshold:
+ Usage: optional
+ Value type: <u32>
+ Definition: indicates the breaking point at which the regulator should
+ switch to high power mode
+
+- qcom,load-bias:
+ Usage: optional
+ Value type: <u32>
+ Definition: specifies a base load on the specific regulator
+
+- qcom,boot-load:
+ Usage: optional
+ Value type: <u32>
+ Definition: specifies the configured load on boot for the specific
+ regulator
+
+- qcom,force-mode-none:
+ Usage: optional (default if no other qcom,force-mode is specified)
+ Value type: <empty>
+ Defintion: indicates that the regulator should not be forced to any
+ particular mode
+
+- qcom,force-mode-lpm:
+ Usage: optional
+ Value type: <empty>
+ Definition: indicates that the regulator should be forced to operate in
+ low-power-mode
+
+- qcom,force-mode-auto:
+ Usage: optional (only available for 8960/8064)
+ Value type: <empty>
+ Definition: indicates that the regulator should be automatically pick
+ operating mode
+
+- qcom,force-mode-hpm:
+ Usage: optional (only available for 8960/8064)
+ Value type: <empty>
+ Definition: indicates that the regulator should be forced to operate in
+ high-power-mode
+
+- qcom,force-mode-bypass: (only for 8960/8064)
+ Usage: optional (only available for 8960/8064)
+ Value type: <empty>
+ Definition: indicates that the regulator should be forced to operate in
+ bypass mode
+
+Standard regulator bindings are used inside switch low-dropout regulator
+subnodes. Check Documentation/devicetree/bindings/regulator/regulator.txt for
+more details.
+
+== Negative Charge Pump
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be one of:
+ "qcom,rpm-pm8058-ncp"
+ "qcom,rpm-pm8921-ncp"
+ "qcom,rpm-pm8921-nldo1200"
+
+- reg:
+ Usage: required
+ Value type: <u32>
+ Definition: resource as defined in <dt-bindings/mfd/qcom_rpm.h>
+
+- qcom,switch-mode-frequency:
+ Usage: required
+ Value type: <u32>
+ Definition: Frequency (Hz) of the swith mode power supply;
+ must be one of:
+ 19200000, 9600000, 6400000, 4800000, 3840000, 3200000,
+ 2740000, 2400000, 2130000, 1920000, 1750000, 1600000,
+ 1480000, 1370000, 1280000, 1200000
+
+Standard regulator bindings are used inside negative charge pump regulator
+subnodes. Check Documentation/devicetree/bindings/regulator/regulator.txt for
+more details.
+
+== Switch
+
+- compatible:
+ Usage: required
+ Value type: <string>
+ Definition: must be one of:
+ "qcom,rpm-pm8058-switch"
+ "qcom,rpm-pm8901-switch"
+ "qcom,rpm-pm8921-switch"
+
+- reg:
+ Usage: required
+ Value type: <u32>
+ Definition: resource as defined in <dt-bindings/mfd/qcom_rpm.h>
+
+
+= EXAMPLE
+
+ #include <dt-bindings/mfd/qcom_rpm.h>
+
+ rpm@108000 {
+ compatible = "qcom,rpm-msm8960";
+ reg = <0x108000 0x1000 0x2011008 0x4>;
+
+ interrupts = <0 19 0>, <0 21 0>, <0 22 0>;
+ interrupt-names = "ack", "err", "wakeup";
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pm8921_s1: pm8921-s1 {
+ compatible = "qcom,rpm-pm8921-smps";
+ reg = <QCOM_RPM_PM8921_S1>;
+
+ regulator-min-microvolt = <1225000>;
+ regulator-max-microvolt = <1225000>;
+ regulator-always-on;
+
+ qcom,switch-mode-frequency = <3200000>;
+ qcom,hpm-threshold = <100000>;
+ };
+ };

...
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