On 10/5/22 06:16, Naresh Solanki wrote:
Hi Rob,
I can add common fan bindings.
Below are the properties that I can think of:
max-rpm, pulse-per-revolution
Let me know what you think.
For max6650, we have:
maxim,fan-microvolt = <12000000>;
maxim,fan-prescale = <4>;
maxim,fan-target-rpm = <1200>;
The voltage can be handled with a regulator, so that won't be necessary.
Prescale (fan divider) values and target rpm seem relevant, though.
The sysfs ABI also permits a minimum rpm which also seems relevant
(lower speeds would indicate fan failures).
Then there are pwm specific parameters for pwm controlled fans.
pwm polarity
pwm frequency
pwm mode (direct current or pulse-width modulation)
Guenter
Regards,
Naresh Solanki
On Fri, 30 Sept 2022 at 01:02, Rob Herring <robh@xxxxxxxxxx> wrote:
On Thu, Sep 22, 2022 at 07:07:17AM +0200, Naresh Solanki wrote:
From: Marcello Sylvester Bauer <sylv@xxxxxxx>
Add Devicetree binding documentation for Maxim MAX6639 temperature
monitor with PWM fan-speed controller.
Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
---
.../bindings/hwmon/maxim,max6639.yaml | 112 ++++++++++++++++++
1 file changed, 112 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
diff --git a/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml b/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
new file mode 100644
index 000000000000..c845fb989af2
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
@@ -0,0 +1,112 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/hwmon/maxim,max6639.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim max6639
+
+maintainers:
+ - Roland Stigge <stigge@xxxxxxxxx>
+
+description: |
+ The MAX6639 is a 2-channel temperature monitor with dual, automatic, PWM
+ fan-speed controller. It monitors its own temperature and one external
+ diode-connected transistor or the temperatures of two external diode-connected
+ transistors, typically available in CPUs, FPGAs, or GPUs.
+
+ Datasheets:
+ https://datasheets.maximintegrated.com/en/ds/MAX6639-MAX6639F.pdf
+
+properties:
+ compatible:
+ enum:
+ - maxim,max6639
+
+ reg:
+ maxItems: 1
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+required:
+ - compatible
+ - reg
+ - "fan@0"
+ - "fan@1"
+
+additionalProperties: false
+
+patternProperties:
+ "^fan@[0-1]$":
+ type: object
+ description: |
+ Represents the two fans and their specific configuration.
+
+ properties:
+ reg:
+ description: |
+ The fan number.
Addresses are a property of the parent (the fan controller), not the
fan.
+ items:
+ minimum: 0
+ maximum: 1
+
+ pwm-polarity:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [0, 1]
+ default: 1
+ description:
+ PWM output is low at 100% duty cycle when this bit is set to zero. PWM
+ output is high at 100% duty cycle when this bit is set to 1.
IIRC, the PWM binding provides for this. The parent should probably be a
PWM provider.
+
+ pulses-per-revolution:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [1, 2, 3, 4]
+ default: 2
+ description:
+ Value specifying the number of pulses per revolution of the controlled
+ FAN.
+
+ maxim,rpm-range:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [2000, 4000, 8000, 16000]
+ default: 4000
+ description:
+ Scales the tachometer counter by setting the maximum (full-scale) value
+ of the RPM range for max6639.
Is this a property of the fan? How is this maxim specific?
The bigger issue here is we need a common fan binding. I'm not inclined
to accept any more fan controller bindings with fan properties until we
do.
Rob
