Linux/AM3358: GPIO configuration

user4950372

Part Number: AM3358

Tool/software: Linux

Hi Experts,

We are in the process of the evaluation w/ AM3358 on BeagleBone Black in our EMI sensitive environment.

Since the GPIO3_21 is required to reconfigure to McASP(ie. 24.576MHz oscillator is no more required), I firstly tried to put a description to disable the 24.576MHz OSC by GPIO1_27 level on the dts files;

/nfs/rootfs/lib/firmware/MEC-GPIO.dts /nfs/roofs/etc/mec/ini_mec.sh

However, after executed the ini_mec.sh, the following messages have been appearred; "cannot create /sys/class/gpio/gpio59/direction: Directory nonexistent" "cannot create /sys/class/gpio/gpio59/value: Directory nonexistent", and the OSC 24.576MHz is not disabled.

Could you please indicate what is still insufficient to control the GPIO1_27 ?

Or, is there any alterenative solution to disable this osc ?

Thanks in advance and Best Regards,

KIMIZUKA

over 7 years ago

0 Biser Gatchev-XID over 7 years ago

TI__Guru**** 393215 points

What Linux version id this?

0 Pavel Botev over 7 years ago

TI__Guru**** 170625 points

Hi Kimizuka,

If you are using recent kernel, you can try to disable this OSC from DTS file. Just remove the OSC related info from the DTS file.

am335x-boneblack.dts

clk_mcasp0_fixed: clk_mcasp0_fixed {
       #clock-cells = <0>;
       compatible = "fixed-clock";
       clock-frequency = <24576000>;
   };

   clk_mcasp0: clk_mcasp0 {
       #clock-cells = <0>;
       compatible = "gpio-gate-clock";
       clocks = <&clk_mcasp0_fixed>;
       enable-gpios = <&gpio1 27 0>; /* BeagleBone Black Clk enable on GPIO1_27 */
   };

   sound {
       compatible = "simple-audio-card";
       simple-audio-card,name = "TI BeagleBone Black";
       simple-audio-card,format = "i2s";
       simple-audio-card,bitclock-master = <&dailink0_master>;
       simple-audio-card,frame-master = <&dailink0_master>;

       dailink0_master: simple-audio-card,cpu {
           sound-dai = <&mcasp0>;
           clocks = <&clk_mcasp0>;
       };

       simple-audio-card,codec {
           sound-dai = <&tda19988>;
       };

Regards,
Pavel

0 user4950372 over 7 years ago in reply to Biser Gatchev-XID

Prodigy 30 points

Hi Biser,

Thank you for your reply.

The Linux version which I'm working is as below;

root@beaglebone:~# cat /etc/debian_version
7.11
root@beaglebone:~# uname -a
Linux beaglebone 3.8.13-bone70 #1 SMP Fri Jan 23 02:15:42 UTC 2015 armv7l GNU/Linux

Thanks and Best Regards,
KIMIZUKA

0 user4950372 over 7 years ago in reply to Pavel Botev

Prodigy 30 points

Hi Pavel,

Thank you for your reply,

Unfortunately, I could not find the "am335x-boneblack.dts" in my working project.
Could you please indicate me the exact path for the file ?

Thanks and Best Regards,
KIMIZUKA

0 Pavel Botev over 7 years ago in reply to user4950372

TI__Guru**** 170625 points

Hi Kimizuka,

The full path to am335x-boneblack.dts is:

{PSDK}/board-support/linux-kernel/arch/arm/boot/dts/am335x-boneblack.dts

Note that only TI PSDK (link below [1]) is supported in this forum. TI PSDK is based on Arago Linux distribution. For Debian Linux support, you should contact the support community in Beagle org.

www.ti.com/.../beaglebk

[1] software-dl.ti.com/.../index_FDS.html

Regards,
Pavel

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Linux/AM3358: GPIO configuration