topic Implement SC18IM700 i2c controller function on platform MSM8996 (kernel 3.18.20) ? in Other NXP Products

Implement SC18IM700 i2c controller function on platform MSM8996 (kernel 3.18.20) ?

yuhang_zhang — Wed, 19 Oct 2016 02:56:24 GMT

Hi everyone:

I'm using the sc18im700 (uart to i2c master) function on the platform msm8996. Now i have some questions during the implement process.

Q1: I found an i2c algorith support for nxp sc18im700(https://lkml.org/lkml/2014/6/9/571). So i need an i2c controller code, Did someone have some experience about using the sc18im700 chip on Linux kernel？

Q2: when i modify the device tree files on kernel , the sc18im700 should be described as an i2c controller or an uart device？ then how to deal with the parameter( i2c address irq clock and so on )?

eg:

  i2c_uart12: uart-nxp-i2c@75b4000 {
  compatible = "nxp,uart-nxp-i2c";
  #address-cells = <1>;
  #size-cells = <0>;
  reg-names = "qup_phys_addr";
  reg = <0x75b4000 0x1000>;
  interrupt-names = "qup_irq";
  interrupts = <0 118 0>;

  clock-names = "iface_clk", "core_clk";
  clocks = <&clock_gcc clk_gcc_blsp2_ahb_clk>,
    <&clock_gcc clk_gcc_blsp2_qup6_i2c_apps_clk>;
  pinctrl-names = "i2c_uart12_active", "i2c_uart12_sleep";
  pinctrl-0 = <&i2c_uart12_active>;
  pinctrl-1 = <&i2c_uart12_sleep>;
};

Re: Implement SC18IM700 i2c controller function on platform MSM8996 (kernel 3.18.20) ?

diegoadrian — Thu, 20 Oct 2016 16:32:52 GMT

Hello Kenio Zhang,

For your first question, you may find more helpful the following code, than the other one.

http://lxr.free-electrons.com/source/drivers/i2c/algos/i2c-algo-bit.c#L57

For your second question, the sc18im700 needs to be described as a UART device. Because, the sc18im700 serves as an interface between the standard UART port and the serial I2C port.

I hope this information could be helpful for you.

Best regards,

Diego.

Re: Implement SC18IM700 i2c controller function on platform MSM8996 (kernel 3.18.20) ?

yuhang_zhang — Wed, 26 Oct 2016 08:14:55 GMT

Hello Diego,

Thanks for you usefull advice, but i feel confused about the main chip communicate with the sc18im700.

I thought two methods to do it .

Fristly, uart driver + i2c controller driver + i2c algorithm

set_data(){

Ttyfd = open(TtyName, O_RDWR | O_NDELAY, 0);

write(Ttyfd,"****", length);

close(Ttyfd);

}

get_data(){

Ttyfd = open(TtyName, O_RDWR | O_NDELAY, 0);

read(Ttyfd, buffer, length);

close(Ttyfd);

}

Secondly, serio driver + i2c controller driver + i2c algorithm , i haven't found the usefull serio information.

So which method should i choose ?

Best regards

Kenio