8148 MCA[4]_AXR[1] set t o GPIO in kernal not working?

yue gu1

8148 ipnc rdk3.5

I want set MCA[4]_AXR[1] to GPIO.

I debug the code in arch/arm/mach-omap2/device.c,

omap2_init_devices()

omap_mux_init_signal("mcasp4_axr1.gpio0_24_mux1", TI81XX_MUX_MODE7 | TI814X_PULL_UP);
omap_mux_init_signal("mcasp5_aclkx.gpio0_25_mux1",TI81XX_MUX_MODE7 | TI814X_PULL_UP);

my trace :

omap_mux_init_signal: Setting signal mcasp4_axr1.gpio0_24_mux1 0x0001 -> 0x20087
omap_mux_init_signal: Setting signal mcasp5_aclkx.gpio0_25_mux1 0x0001 -> 0x20087

but the Voltage on GPIO24,GPIO25 is low;

my question:

1. I think the problem maybe mux pin setting on GPIO24,GPIO25 failed.

2. How can I set mux pin to GPIO on kernal ?

Look forwards for your answer!!!!

over 10 years ago

0 Pavel Botev over 10 years ago

TI__Guru**** 170625 points

Hi Yue,

What is the value of the PINCNTL54 (addr 0x481408D4) register after kernel boot up? You can check it with the devmem2 tool. With the default kernel I have the value of 0x000C0001:

root@dm814x-evm:~# devmem2 0x481408D4
/dev/mem opened.
Memory mapped at address 0x40282000.
Read at address 0x481408D4 (0x402828d4): 0x000C0001

The wiki page that explain pinmux is:

http://processors.wiki.ti.com/index.php/TI81XX_PSP_User_Guide#TI814X.2FTI813X

I have modified linux-kernel/arch/arm/mach-omap2/board-ti8148evm.c as below:

#ifdef CONFIG_OMAP_MUX
static struct omap_board_mux board_mux[] __initdata = {
TI814X_MUX(MCASP4_AXR1, (OMAP_MUX_MODE7 | TI814X_PULL_UP)), /* gpio0_24_mux1 */
{ .reg_offset = OMAP_MUX_TERMINATOR },
};

Thus with this new kernel, I have:

root@dm814x-evm:~# devmem2 0x481408D4
/dev/mem opened.
Memory mapped at address 0x40254000.
Read at address 0x481408D4 (0x402548d4): 0x00020080

Which means that GP0[24] signal is selected on this physical pin (J4) with pull-up enable.

BR
Pavel

0 yue gu1 over 10 years ago in reply to Pavel Botev

Intellectual 865 points

thanks for your reply first.

root@dm814x-evm:~# devmem2 0x481408D4
/dev/mem opened.
Memory mapped at address 0x4031f000.
Read at address 0x481408D4 (0x4031f8d4): 0x00020080

but J4 still not pull-up...

There are other reasons may?

0 Pavel Botev over 10 years ago in reply to yue gu1

TI__Guru**** 170625 points

Yue,

yue gu1 said:
but J4 still not pull-up...

Please check:

1. Check if you have external pull down resistor attached to J4

2. Check if you have external device connected to the J4 pin, which drives it low (in TI EVM, J4 is connected to expansion connector)

3. Check if you are aligned with the below wiki page:

http://processors.wiki.ti.com/index.php/TI81XX_PSP_GPIO_Driver_User_Guide

Set GPIO24 pin as output and set its output to 1.

4. Check DM814x Silicon errata, Advisory 2.1.88. You can set bit 19 like below:

TI814X_MUX(MCASP4_AXR1, (OMAP_MUX_MODE7 | TI814X_PULL_UP | TI814X_SLEW_SLOW)), /* gpio0_24_mux1 */

Thus you should have the value of 0x000A0080. Try with this value also.

5. Check DM814x Silicon errata, Advisory 2.1.87. You can set bit 18 like below:

TI814X_MUX(MCASP4_AXR1, (OMAP_MUX_MODE7 | TI814X_PULL_UP | TI814X_SLEW_SLOW | TI814X_INPUT_EN)), /* gpio0_24_mux1 */

Thus you should have the value of 0x000E0080. Thus J4 pin is bidirectional. Try with this value also.

Regards,
Pavel

0 yue gu1 over 10 years ago in reply to Pavel Botev

Intellectual 865 points

thanks for your answer first.

the setting is ok.

0 Pavel Botev over 10 years ago in reply to yue gu1

TI__Guru**** 170625 points

Yue,

yue gu1 said:
the setting is ok.

Do you mean you have fix it (high level on J4 pin)?

BR
Pavel

0 yue gu1 over 10 years ago in reply to Pavel Botev

Intellectual 865 points

thanks again for your answer.

I fixed it with your help.

It's due to my evm board question.

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8148 MCA[4]_AXR[1] set t o GPIO in kernal not working?