i.MX Processors中的主题 Re: How to set external RTC in kernel

How to set external RTC in kernel

Mihan — Wed, 08 Jul 2020 06:24:47 GMT

Some days ago，I asked a question about RTC RTC always reset to 19700101

After investigation, I find it can not register the external RTC (BM8563ESA, I2C RTC) if I close all the on-cpu RTC in "menuconfig". And the RTC_VBAT is unused so that the on-cpu RTC which I have been using will be reset after power off.

So could you please give me a hand for adding this I2C RTC into kernel.

now my devices tree for this external RTC:

&i2c3 {
   clock-frequency = <100000>;
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_i2c3>;
   status = "okay";
   rtc@51{
      compatible = "pcf8563";
      reg = <0x51>;
   };
   hdmi: edid@50 {
      compatible = "fsl,imx6-hdmi-i2c";
      reg = <0x50>;
      status = "okay";
   };
};

Regards

Mihan

Re: How to set external RTC in kernel

karangajjar — Wed, 08 Jul 2020 13:06:08 GMT

Hi 铭恒李 ,

It seems like your compatible property is not getting matched with the driver's compatible property name. You can check drivers/rtc/rtc-pcf8563.c at least once and make sure your node's compatible property matches with driver's compatible property. (here compatible = "nxp,pcf8563")

You can refer Documentation/devicetree/bindings/rtc/pcf8563.txt. to add a node of etc.

Also, make sure you have enabled this driver with the help of menuconfig.

Regards,

Karan Gajjar

Re: How to set external RTC in kernel

Mihan — Wed, 15 Jul 2020 03:07:49 GMT

Thanks

I have solve this problem.

First, I found I used the on-cpu RTC before.

Second, I found the I2C address (get from `i2cdetect` and set in the device tree) was mismatched.

So, now I close all the on-cpu RTC on `make menuconfig-> device drivers-> Real time clock`, and make sure the all about pcf8563 are opened.

it works well for my device.

Regards

Mihan

Re: How to set external RTC in kernel

karangajjar — Wed, 15 Jul 2020 04:20:18 GMT

Hi 铭恒李,

We are glad you solved your issue.

Kindly let us know in case of any other concerns.

Regards,

Karan Gajjar