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Configuring CCM_CLKO1 as generic clock with 3.10.x kernel

Question asked by Piero Pezzin on Feb 11, 2016
Latest reply on Dec 17, 2016 by femy varghese

Hello everyone,

 

on a custom i.MX6-based board I'm trying to configure the CCM_CLKO1 signal as a generic clock source for an audio codec connected to the SSI interface. I have modified the device tree setting the pinmux as reported below:

 

&i2c2 {

        codec: tlv320aic3x@18 {

        compatible = "ti,tlv320aic3x";

        reg = <0x18>;

        clocks = <&clks 169>;

        AVDD-supply = <&reg_3p3v>;

        IOVDD-supply = <&reg_3p3v>;

        DRVDD-supply = <&reg_3p3v>;

        DVDD-supply = <&reg_1p8v>;

        status = "okay";

 

    };

};

 

&iomuxc {

        tlv320aic3x {

        pinctrl_tlv320aic3x_1: tlv320aic3x_codecgrp-1{

            fsl,pins = <

                MX6QDL_PAD_CSI0_DAT5__AUD3_TXD 0x130b0

                MX6QDL_PAD_CSI0_DAT6__AUD3_TXFS 0x130b0

                MX6QDL_PAD_CSI0_DAT7__AUD3_RXD 0x130b0

                MX6QDL_PAD_CSI0_DAT4__AUD3_TXC 0x130b0

                MX6QDL_PAD_CSI0_MCLK__CCM_CLKO1 0x130b0

            >;

        };

    };

};

 

&ssi1 {

    status = "okay";

};

 

&audmux {

    pinctrl-names = "default";

    pinctrl-0 = <&pinctrl_tlv320aic3x_1>;

    status = "okay";

};

 

In the "codec" device tree entry, I've added the

 

clocks = <&clks 169>;

 

property, which in my understanding should select the cko1 signal as the master clock.

 

Unfortunately, I don't see any activity on the CSI0_MCLK/CCM_CLKO1 pin. I've checked the device tree hierarchy to make sure that no other peripherals are using that pin. I've also tried adding the following code to the arch/arm/mach-imx/clk-imx6q.c file

 

printk("Trying to set CLKO1...\n");

    ret = clk_set_parent(clk[cko1_sel], clk[pll4_audio_div]);

    if (!ret){

ret = clk_set_parent(clk[cko], clk[cko1]);
printk("CLKO1 set parent\n");

    }

    if (ret)

pr_warn("failed to set up CLKO1: %d\n", ret);

 

in the same way that cko2 is configured, but still with no luck and I'm wondering how I'm doing wrong..

 

Could someone help me understand which are the required steps to correctly configure the CCM_CLKO1 signal?

 

Any help will be greatly appreciated.

 

Thanks and best regards

 

Piero Pezzin

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