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A40i修改SPI频率

2024-8-28 10:49| 发布者: hzjmlb| 查看: 76| 评论: 0

类目：知识库 > A40i/T3系列产品文档编号: 1497

在设备树中修改对应spi时钟输入

linux-3.10\arch\arm\boot\dts\sun8iw11p1-OKA40i_C.dts

&spi2 {

status = "okay";

clock-frequency = <60000000>;

spidev_cs0:spi2_cs0@0{

#address-cells=<1>;

#size-cells=<1>;

compatible = "spidev";

spi-max-frequency = <80000000>; // 这个数值不能大于80MHz，spi驱动会检查

reg = <0>;

mode=<0>;

};

spidev_cs1:spi2_cs1@1{

#address-cells=<1>;

#size-cells=<1>;

compatible = "spidev";

spi-max-frequency = <80000000>;

reg = <1>;

mode=<0>;

};

linux-3.10\arch\arm\boot\dts\sun8iw11p1-pwm1.dtsi

spi2: spi@01c17000 {

#address-cells = <1>;

#size-cells = <0>;

compatible = "allwinner,sun8i-spi";

device_type = "spi2";

reg = <0x0 0x01c17000 0x0 0x1000>;

interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>;

clocks = <&clk_pll_periph0>, <&clk_spi2>;

clock-frequency = <60000000>; // 修改时钟频率

pinctrl-names = "default", "sleep";

pinctrl-0 = <&spi2_pins_a &spi2_pins_b>;

pinctrl-1 = <&spi2_pins_c>;

spi2_cs_number = <2>;

spi2_cs_bitmap = <3>;

status = "okay"; // 改为okay

};

修改完毕后在系统中可以查看对应频率

# mount -t debugfs none /sys/kernel/debug

# cat /sys/kernel/debug/clk/clk_summary

clock enable_cnt prepare_cnt rate

---------------------------------------------------------------------

pll_periph0 3 3 600000000 # 600MHz

spi2 1 1 60000000 # 60MHz

spi0 1 1 100000000 # 100MHz

spi2被成功修改到了60MHz的输入

使用飞凌测试应用测试30MHz是否工作正常

# fltest_spi -s 30000000

spi mode: 0

bits per word: 8

max speed: 30000000 Hz (30000 KHz)

FF FF FF FF FF FF

40 00 00 00 00 95

FF FF FF FF FF FF

DE AD BE EF BA AD

F0 0D

已解决

未解决

只是看看

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