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GMT G762/763 fan speed PWM controller is connected directly to a fan and performs closed-loop or open-loop control of the fan speed. Two modes - PWM or DC - are supported by the chip. Introduced driver provides various knobs to control the operations of the chip (via sysfs interface). Specific characteristics of the system can be passed either using board init code or via DT. Documentation for both the driver and DT bindings are also provided. Signed-off-by: Arnaud Ebalard <arno@natisbad.org> Tested-by: Simon Guinot <simon.guinot@sequanux.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
48 lines
1.3 KiB
Plaintext
48 lines
1.3 KiB
Plaintext
GMT G762/G763 PWM Fan controller
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Required node properties:
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- "compatible": must be either "gmt,g762" or "gmt,g763"
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- "reg": I2C bus address of the device
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- "clocks": a fixed clock providing input clock frequency
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on CLK pin of the chip.
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Optional properties:
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- "fan_startv": fan startup voltage. Accepted values are 0, 1, 2 and 3.
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The higher the more.
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- "pwm_polarity": pwm polarity. Accepted values are 0 (positive duty)
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and 1 (negative duty).
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- "fan_gear_mode": fan gear mode. Supported values are 0, 1 and 2.
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If an optional property is not set in .dts file, then current value is kept
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unmodified (e.g. u-boot installed value).
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Additional information on operational parameters for the device is available
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in Documentation/hwmon/g762. A detailed datasheet for the device is available
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at http://natisbad.org/NAS/refs/GMT_EDS-762_763-080710-0.2.pdf.
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Example g762 node:
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clocks {
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#address-cells = <1>;
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#size-cells = <0>;
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g762_clk: fixedclk {
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compatible = "fixed-clock";
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#clock-cells = <0>;
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clock-frequency = <8192>;
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}
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}
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g762: g762@3e {
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compatible = "gmt,g762";
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reg = <0x3e>;
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clocks = <&g762_clk>
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fan_gear_mode = <0>; /* chip default */
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fan_startv = <1>; /* chip default */
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pwm_polarity = <0>; /* chip default */
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};
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