Linux/PROCESSOR-SDK-AM437X: GPIO problem

Beata

Part Number: PROCESSOR-SDK-AM437X
Other Parts Discussed in Thread: AM4372

Tool/software: Linux

Hi sir:

could you do me a favor?

there is a problem that the gpio number, that the gpio works as what i wanted when using the gpio number in the directory "/sys/class/gpio/" , paired address is not as i wanted when i go to find the address that corresponed to the gpio number in the file "pins" under the directory " /sys/kernel/debug/pinctrl/" in board linux system.

The follow is the code in the device tree.

uart3_pins: uart3_pins {
  pinctrl-single,pins = <
   AM4372_IOPAD(0xa28, PIN_INPUT | MUX_MODE0)  /* uart3_rxd.uart3_rxd */
   AM4372_IOPAD(0xa2c, PIN_OUTPUT_PULLDOWN | MUX_MODE0) /* uart3_txd.uart3_txd */
   AM4372_IOPAD(0xa30, PIN_INPUT_PULLUP | MUX_MODE0) /* uart3_ctsn.uart3_ctsn */
   AM4372_IOPAD(0xa34, PIN_OUTPUT_PULLDOWN | MUX_MODE0) /* uart3_rtsn.uart3_rtsn */
   AM4372_IOPAD(0x8c8, PIN_OUTPUT | MUX_MODE7)/* gpio2-16 */
   AM4372_IOPAD(0x8cc, PIN_OUTPUT | MUX_MODE7)/* gpio2-17 */
   AM4372_IOPAD(0x8e0, PIN_OUTPUT | MUX_MODE7) /* gpio2-22 */
   AM4372_IOPAD(0x8e4, PIN_OUTPUT | MUX_MODE7) /* gpio2-23 */
  >;
};

-----------

&uart3 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&uart3_pins>;
};

when I configure the gpio2_16,17,22,23 in the node uart3 ,the gpio80,that accumulated by the method that you offered (2x32+16 ), can works well as what i wanted .

But when i departed the four gpio configuration ,using the follow code in the device tree, the gpio80 can't work as wanted.

gpio_my_pins: gpio_mux_pins {
pinctrl-single,pins = <

   AM4372_IOPAD(0x8c8, PIN_OUTPUT | MUX_MODE7)/* gpio2-16 */
   AM4372_IOPAD(0x8cc, PIN_OUTPUT | MUX_MODE7)/* gpio2-17 */
   AM4372_IOPAD(0x8e0, PIN_OUTPUT | MUX_MODE7) /* gpio2-22 */
   AM4372_IOPAD(0x8e4, PIN_OUTPUT | MUX_MODE7) /* gpio2-23 */
  >;
};

&gpio2 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&gpio_my_pins>;
};

And there is a problem very serious, when the gpio 80 works ,i find the pin's address in the file "/sys/kernel/debug/pinctrl/pins" is 0x44e10940 .But I think the right address should be 0x44e108c8.

So ,what cause it? the follow is the file named "pins" in the directory "/sys/kernel/debug/pinctrl/".

pin 47 (PIN47) 44e108bc 08050007 pinctrl-single

pin 48 (PIN48) 44e108c0 08050007 pinctrl-single

pin 49 (PIN49) 44e108c4 08050007 pinctrl-single

pin 50 (PIN50) 44e108c8 00010007 pinctrl-single

pin 51 (PIN51) 44e108cc 00010007 pinctrl-single

pin 52 (PIN52) 44e108d0 08050007 pinctrl-single

pin 53 (PIN53) 44e108d4 08050007 pinctrl-single

pin 54 (PIN54) 44e108d8 08050007 pinctrl-single

pin 55 (PIN55) 44e108dc 08050007 pinctrl-single

pin 56 (PIN56) 44e108e0 00010007 pinctrl-single

pin 57 (PIN57) 44e108e4 00010007 pinctrl-single

pin 58 (PIN58) 44e108e8 08040007 pinctrl-single

pin 59 (PIN59) 44e108ec 08050007 pinctrl-single

pin 60 (PIN60) 44e108f0 00050000 pinctrl-single

pin 61 (PIN61) 44e108f4 00050000 pinctrl-single

pin 62 (PIN62) 44e108f8 00050000 pinctrl-single

pin 63 (PIN63) 44e108fc 00050000 pinctrl-single

pin 64 (PIN64) 44e10900 00050000 pinctrl-single

pin 65 (PIN65) 44e10904 00050000 pinctrl-single

pin 66 (PIN66) 44e10908 00040007 pinctrl-single

pin 67 (PIN67) 44e1090c 00040007 pinctrl-single

pin 68 (PIN68) 44e10910 00040007 pinctrl-single

pin 69 (PIN69) 44e10914 00010002 pinctrl-single

pin 70 (PIN70) 44e10918 00050002 pinctrl-single

pin 71 (PIN71) 44e1091c 00010002 pinctrl-single

pin 72 (PIN72) 44e10920 00010002 pinctrl-single

pin 73 (PIN73) 44e10924 00010002 pinctrl-single

pin 74 (PIN74) 44e10928 00010002 pinctrl-single

pin 75 (PIN75) 44e1092c 00010002 pinctrl-single

pin 76 (PIN76) 44e10930 00050002 pinctrl-single

pin 77 (PIN77) 44e10934 00050002 pinctrl-single

pin 78 (PIN78) 44e10938 00050002 pinctrl-single

pin 79 (PIN79) 44e1093c 00050002 pinctrl-single

pin 80 (PIN80) 44e10940 00050002 pinctrl-single

pin 81 (PIN81) 44e10944 00040007 pinctrl-single

pin 82 (PIN82) 44e10948 00050000 pinctrl-single

pin 83 (PIN83) 44e1094c 00010000 pinctrl-single

pin 84 (PIN84) 44e10950 08060007 pinctrl-single

Your answer is very appreciated!

Thanks!

over 7 years ago

0 Kemal R. Shakir over 7 years ago

TI__Guru 55345 points

Hello lihua,

Please, move the &gpio_my_pins from &gpio2 to pinctrl-0 in &am43xx_pinmux as has done in this thread.

Best regards,
Kemal

0 Beata over 7 years ago in reply to Kemal R. Shakir

Prodigy 220 points

Hello Kemal,

I connect the gpio2 to the button and configure the pin as input,

AM4372_IOPAD(0x8a8, PIN_INPUT | MUX_MODE7) /* dss_data2.gpio2_8 */

Whether there is a register to read the level change with devmem2 command after I press this button?

Thanks,

Lihua

0 Kemal R. Shakir over 7 years ago in reply to Beata

TI__Guru 55345 points

Yes, there is a register: 0x481ac13c

0 Beata over 7 years ago in reply to Kemal R. Shakir

Prodigy 220 points

Hello Kemal,

I read the register:0x481ac13c, but after I pressed the button, the read value did not change when I set gpio2_8 as input pin.

In the AM437x Technical Reference Manual,when I set gpio2_8 as output pin, change the level, the reading value will change.

GPIO_DATAOUT Register (offset = 13Ch) [reset = 0h] The GPIO_DATAOUT register is used for setting the value of the GPIO output pins.

GPIO_DATAIN Register (offset = 138h) [reset = 0h] The GPIO_DATAIN register is used to register the data that is read from the GPIO pins.

The following message is the log:

root@am437x-evm:/sys/class/gpio/gpio72# echo in > direction
root@am437x-evm:/sys/class/gpio/gpio72# cat value
0
root@am437x-evm:/sys/class/gpio/gpio72# cat direction
in
root@am437x-evm:/sys/class/gpio/gpio72# devmem2 0x481ac13c
/dev/mem opened.
Memory mapped at address 0xb6fa7000.
Read at address 0x481AC13C (0xb6fa713c): 0x00420000
root@am437x-evm:/sys/class/gpio/gpio72# devmem2 0x481ac13c
/dev/mem opened.
Memory mapped at address 0xb6fd9000.
Read at address 0x481AC13C (0xb6fd913c): 0x00420000
root@am437x-evm:/sys/class/gpio/gpio72#
root@am437x-evm:/sys/class/gpio/gpio72# devmem2 0x481ac138
/dev/mem opened.
Memory mapped at address 0xb6f5a000.
Read at address 0x481AC138 (0xb6f5a138): 0x00000600
root@am437x-evm:/sys/class/gpio/gpio72# devmem2 0x481ac138
/dev/mem opened.
Memory mapped at address 0xb6f7e000.
Read at address 0x481AC138 (0xb6f7e138): 0x00000600
root@am437x-evm:/sys/class/gpio/gpio72#
root@am437x-evm:/sys/class/gpio/gpio72# echo high > direction
root@am437x-evm:/sys/class/gpio/gpio72# cat direction
out
root@am437x-evm:/sys/class/gpio/gpio72# cat value
1
root@am437x-evm:/sys/class/gpio/gpio72# devmem2 0x481ac13c
/dev/mem opened.
Memory mapped at address 0xb6f2b000.
Read at address 0x481AC13C (0xb6f2b13c): 0x00420100
root@am437x-evm:/sys/class/gpio/gpio72# echo 0 > value
root@am437x-evm:/sys/class/gpio/gpio72# devmem2 0x481ac13c
/dev/mem opened.
Memory mapped at address 0xb6fa0000.
Read at address 0x481AC13C (0xb6fa013c): 0x00420000

When I set gpio2_8 as input pin,the value of 0x481ac138 register no change after I press the button.

What is the reason for this?

Do I use the GPIO_DATAOUT Register register when I press the button to read the level change?

Thanks.

Lihua

0 user522982188 over 7 years ago in reply to Kemal R. Shakir

Prodigy 150 points

Hello Kemal,

I can already read the level change when I press or release the button with the 0x481ac138（GPIO_DATAIN） register.

However, when the value of the register is read, the bus error will often appear as follows.

root@am437x-evm:~# devmem2 0x481ac138
/dev/mem opened.[ 293.642911] Unhandled fault: external abort on non-linefetch (0x1018) at 0xb6ff7138
[ 293.651543] pgd = ee50c000
[ 293.654255] [b6ff7138] *pgd=bcc93831
[ 293.657963] ------------[ cut here ]------------
[ 293.662630] WARNING: CPU: 0 PID: 339 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x25c/0x36c
[ 293.671938] 44000000.ocp:L3 Custom Error: MASTER M2 (64-bit) TARGET L4_PER_0 (Read): Data Access in User mode during Functional access
[ 293.684005] Modules linked in:
[ 293.687084] CPU: 0 PID: 339 Comm: devmem2 Tainted: G W 4.9.69-g9ce43c71ae #57
[ 293.695344] Hardware name: Generic AM43 (Flattened Device Tree)
[ 293.701258] Backtrace:
[ 293.703758] [<c010b7d0>] (dump_backtrace) from [<c010ba8c>] (show_stack+0x18/0x1c)
[ 293.711336] r7:00000009 r6:00000000 r5:c09b9294 r4:ee4a5c58
[ 293.717021] [<c010ba74>] (show_stack) from [<c03c53f4>] (dump_stack+0x24/0x28)
[ 293.724260] [<c03c53d0>] (dump_stack) from [<c012d978>] (__warn+0xe8/0x100)
[ 293.731230] [<c012d890>] (__warn) from [<c012d9d0>] (warn_slowpath_fmt+0x40/0x48)
[ 293.738724] r9:00000000 r8:ef11d290 r7:c09b936c r6:00000002 r5:c09b91c0 r4:c09b9264
[ 293.746480] [<c012d994>] (warn_slowpath_fmt) from [<c03f45a0>] (l3_interrupt_handler+0x25c/0x36c)
[ 293.755348] r3:ef11d0c0 r2:c09b9264
[ 293.758924] r4:80080003
[ 293.761485] [<c03f4344>] (l3_interrupt_handler) from [<c016b444>] (__handle_irq_event_percpu+0xb4/0x144)
[ 293.770970] r10:c0c47ef0 r9:ef103400 r8:00000015 r7:ee4a5d7c r6:00000000 r5:ef103400
[ 293.778794] r4:ef11d640
[ 293.781348] [<c016b390>] (__handle_irq_event_percpu) from [<c016b4f8>] (handle_irq_event_percpu+0x24/0x60)
[ 293.791007] r10:bea67bb8 r9:ee4a4000 r8:ef008000 r7:ee4a5f40 r6:00000000 r5:ef103400
[ 293.798830] r4:ef103400
[ 293.801381] [<c016b4d4>] (handle_irq_event_percpu) from [<c016b598>] (handle_irq_event+0x64/0x90)
[ 293.810249] r5:c0c082c8 r4:ef103400
[ 293.813845] [<c016b534>] (handle_irq_event) from [<c016e85c>] (handle_fasteoi_irq+0xc0/0x200)
[ 293.822364] r5:c0c082c8 r4:ef103400
[ 293.825957] [<c016e79c>] (handle_fasteoi_irq) from [<c016a640>] (generic_handle_irq+0x2c/0x3c)
[ 293.834569] r7:ee4a5f40 r6:00000000 r5:00000015 r4:c0c1f550
[ 293.840240] [<c016a614>] (generic_handle_irq) from [<c016ace8>] (__handle_domain_irq+0x5c/0xb0)
[ 293.848944] [<c016ac8c>] (__handle_domain_irq) from [<c0101520>] (gic_handle_irq+0x40/0x6c)
[ 293.857302] r9:ee4a4000 r8:fa241100 r7:fa240100 r6:ee4a5e30 r5:fa24010c r4:c0c02c14
[ 293.865052] [<c01014e0>] (gic_handle_irq) from [<c010c4cc>] (__irq_svc+0x6c/0xa8)
[ 293.872531] Exception stack(0xee4a5e30 to 0xee4a5e78)
[ 293.877589] 5e20: 00404100 00000100 c0c4a200 00000000
[ 293.885772] 5e40: 00000202 00000012 00000000 00000000 ef008000 ee4a4000 bea67bb8 ee4a5edc
[ 293.893952] 5e60: c0c4a240 ee4a5e80 c0131660 c0131128 600e0113 ffffffff
[ 293.900576] r9:ee4a4000 r8:ef008000 r7:ee4a5e64 r6:ffffffff r5:600e0113 r4:c0131128
[ 293.908329] [<c0131090>] (__do_softirq) from [<c0131660>] (irq_exit+0x140/0x144)
[ 293.915733] r10:bea67bb8 r9:ee4a4000 r8:ef008000 r7:00000000 r6:00000000 r5:00000012
[ 293.923555] r4:c0c1f550
[ 293.926106] [<c0131520>] (irq_exit) from [<c016acec>] (__handle_domain_irq+0x60/0xb0)
[ 293.933944] [<c016ac8c>] (__handle_domain_irq) from [<c0101520>] (gic_handle_irq+0x40/0x6c)
[ 293.942302] r9:ee4a4000 r8:fa241100 r7:fa240100 r6:ee4a5f40 r5:fa24010c r4:c0c02c14
[ 293.950049] [<c01014e0>] (gic_handle_irq) from [<c010c4cc>] (__irq_svc+0x6c/0xa8)
[ 293.957526] Exception stack(0xee4a5f40 to 0xee4a5f88)
[ 293.962591] 5f40: ee4a5fb0 00000001 00000000 600e0010 ee4a4000 00000000 ee4a5fb0 10c53c7d
[ 293.970774] 5f60: 00000000 ee4a4000 bea67bb8 ee4a5fac ee4a5fb0 ee4a5f90 c0107d20 c010b3b8
[ 293.978944] 5f80: 600e0113 ffffffff
[ 293.982447] r9:ee4a4000 r8:00000000 r7:ee4a5f74 r6:ffffffff r5:600e0113 r4:c010b3b8
[ 293.990205] [<c010b368>] (do_work_pending) from [<c0107d20>] (slow_work_pending+0xc/0x20)
[ 293.998385] r7:10c53c7d r6:ffffffff r5:600e0010 r4:00010744
[ 294.004040] ---[ end trace 372bd7641dd79d76 ]---

Memory mapped at address 0xb6ff7000.
Bus error (core dumped)
root@am437x-evm:~#

Now，I boot the target board from SD card，Will it be a problem with the file system in the SD card, or the device tree configuration?

How should I solve this problem?

Thanks，

Lihua

0 Kemal R. Shakir over 7 years ago in reply to user522982188

TI__Guru 55345 points

You are trying to access address which is not memory mapped. Please, post me the output of this command: cat /sys/kernel/debug/gpio

0 user522982188 over 7 years ago in reply to Kemal R. Shakir

Prodigy 150 points

Hi Kemal,

The following message is the output with the command:

root@am437x-evm:~# cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-31, parent: platform/44e07000.gpio, gpio:
gpio-6 ( |cd ) in hi IRQ
gpio-16 ( |sysfs ) out hi

gpiochip1: GPIOs 32-63, parent: platform/4804c000.gpio, gpio:

gpiochip2: GPIOs 64-95, parent: platform/481ac000.gpio, gpio:

gpiochip3: GPIOs 96-127, parent: platform/48322000.gpio, gpio:
gpio-100 ( |matrix_kbd_col ) out hi
gpio-101 ( |matrix_kbd_row ) in lo IRQ
gpio-102 ( |matrix_kbd_row ) in lo IRQ
gpio-109 ( |matrix_kbd_col ) out hi

Thanks,
Lihua

0 Kemal R. Shakir over 7 years ago in reply to user522982188

TI__Guru 55345 points

Now echo 64 > /sys/class/gpio/export and accessing address 0x481ac138 will not cause non-linefetch.

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Linux/PROCESSOR-SDK-AM437X: GPIO problem