This binding provides interface for adding values related to ASPEED
AST2400/2500 PWM and Fan tach controller support.
The PWM controller can support upto 8 PWM output ports.
The Fan tach controller can support upto 16 tachometer inputs.
PWM clock types M, N and 0 are three types just to have three independent
PWM sources.
Signed-off-by: Jaghathiswari Rankappagounder Natarajan <ja...@google.com>
---
.../devicetree/bindings/hwmon/aspeed-pwm-tacho.txt | 153 +++++++++++++++++++++
1 file changed, 153 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
diff --git a/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
b/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
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index 000000000000..8f346409ee8c
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+++ b/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
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+ASPEED AST2400/AST2500 PWM and Fan Tacho controller device driver
+
+The ASPEED PWM controller can support upto 8 PWM outputs. The ASPEED Fan Tacho
+controller can support upto 16 tachometer inputs. The PWM controller supports
+3 types of frequency mode PWM for fan speed control. PWM clock types M, N and 0
+are 3 types of frequency mode PWM just to have 3 independent PWM sources.
+
+Required properties for pwm_tacho node:
+- #address-cells : should be 1.
+
+- #size-cells : should be 1.
+
+- reg : address and length of the register set for the device.
+
+- pinctrl-names : a pinctrl state named "default" must be defined.
+
+- pinctrl-0 : phandle referencing pin configuration of the AST2400/AST2500 PWM
+ ports.
+
+- compatible : should be "aspeed,aspeed2400-pwm-tacho" for AST2400 or
+ "aspeed,aspeed2500-pwm-tacho" for AST2500.
+
+- clocks : a fixed clock providing input clock frequency(PWM
+ and Fan Tach clock)
+
+type_values subnode format:
+===========================
+Under type_values subnode there can be upto 3 child nodes indicating type M/N/O
+values. Atleast one child node is required.
+
+Required properties for the child node(type M/N/O):
+- pwm_period : indicates type M/N/O PWM period, as per the AST2400/AST2500
+ datasheet. integer value in the range 0 to 255.
+
+- pwm_clock_division_l : indicates type M/N/O PWM clock division L value,
+ as per the AST2400/AST2500 datasheet.
+ integer value in the range 0 to 15.
+ 0 here indicates divide 1, 1 indicates divide 2,
+ 2 indicates divide 4, 3 indicates divide 6, and so on
+ till 15 indicates divide 30.
+
+- pwm_clock_division_h : indicates type M/N/O PWM clock division H value,
+ as per the AST2400/AST2500 datasheet.
+ integer value in the range 0 to 15.
+ 0 here indicates divide 1, 1 indicates divide 2,
+ 2 indicates divide 4, 3 indicates divide 8, and so on
+ till 15 indicates divide 32768.
+
+- fan_tach_enable : indicates fan tach enable of type M/N/O as per the
+ AST2400/AST2500 datasheet. boolean value.
+
+- fan_tach_clock_division : indicates fan tach clock division as per the
+ AST2400/AST2500 datasheet.
+ integer value in the range 0 to 7.
+ 0 indicates divide 4, 1 indicates divide 16,
+ 2 indicates divide 64, 3 indicates divide 256
+ and so on till 7 indicates divide 65536.
+
+- fan_tach_mode_selection : indicates fan tach mode mode selection as per the
+ AST2400/AST2500 datasheet. integer value in the
+ range 0 to 2. 0 indicates falling edge, 1 indicates
+ rising edge and 2 indicates both edges.
+
+- fan_tach_period : indicates fan tach period as per the AST2400/AST2500
+ datasheet. integer value (can be upto 16 bits long).
+
+pwm_port subnode format:
+========================
+Under pwm_port subnode there can upto 8 child nodes each indicating values
+for one of the 8 PWM output ports.
+
+Required properties for each child node(starting from PWM A through PWM H):
+- enable : enable PWM #X port, X ranges from A through H. boolean value.
+
+- type : indicates type selection value of PWM #X port, X ranges from A
+ through H. integer value in the range 0 to 2;
+ 0 indicates type M, 1 indicates type N, 2 indicates type O.
+
+- fan_ctrl : set the PWM fan control initial value. integer value between
+ 0(off) and 255(full speed).
+
+fan_tach_channel subnode format:
+================================
+Under fan_tach_channel subnode there can be upto 16 child nodes each indicating
+values for one of the 16 fan tach channels.
+
+Required properties for each child node(starting from fan tach #0 through
+fan tach #16):
+- fan-ctrl-gpios : should specify the tachometer input pin on the hardware.
+
+- enable : enable fan tach #X, X ranges from 0 through 16. boolean value.
+
+- pwm_source : indicates PWM source of fan tach #X, X ranges from 0 through 16.
+ integer value in the range 0 to 7. 0 indicates PWM port A,
+ 1 indicates PWM port B and so on till 7 indicates PWM port H.
+
+Examples:
+
+pwm_tacho_fixed_clk: fixedclk {
+ compatible = "fixed-clock";
+ #clock-cells = <0>;
+ clock-frequency = <24000000>;
+}
+
+pwm_tacho: pwm-tacho-controller@1e786000 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ reg = <0x1E786000 0x1000>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>;
+ compatible = "aspeed,aspeed2500-pwm-tacho";
+ clocks = <&pwm_tacho_fixed_clk>;
+ type_values {
+ typem {
+ pwm_period = /bits/ 8 <0x5F>;
+ pwm_clock_division_h = /bits/ 8 <0x00>;
+ pwm_clock_division_l = /bits/ 8 <0x05>;
+ fan_tach_enable;
+ fan_tach_clock_division = /bits/ 8 <0x00>;
+ fan_tach_mode_selection = /bits/ 8 <0x00>;
+ fan_tach_period = /bits/ 16 <0x1000>;
+ };
+ };
+
+ pwm_port {
+ pwm_port0 {
+ enable;
+ type = /bits/ 8 <0x00>;
+ fan_ctrl = /bits/ 8 <0xFF>;
+ };
+
+ pwm_port1 {
+ enable;
+ type = /bits/ 8 <0x00>;
+ fan_ctrl = /bits/ 8 <0xFF>;
+ };
+ };
+
+ fan_tach_channel {
+ fan_tach0 {
+ fan-ctrl-gpios = <&gpio ASPEED_GPIO(O, 0)
GPIO_ACTIVE_HIGH>;
+ enable;
+ pwm_source = /bits/ 8 <0x00>;
+ };
+
+ fan_tach1 {
+ fan-ctrl-gpios = <&gpio ASPEED_GPIO(O, 1)
GPIO_ACTIVE_HIGH>;
+ enable;
+ pwm_source = /bits/ 8 <0x01>;
+ };
+
+ };
+};
--
2.11.0.390.gc69c2f50cf-goog
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