SPI2 (H14, H15, G15, G16) as GPIO in tx2

Autonomous Machines Jetson & Embedded Systems Jetson TX2
#1

Hi, I need I little help with gpio. I will appreciate your time.
I am new in this.

I know how to map the SPI1 pins as gpio .

SPI1_CLK - G13 - GPIO3_PN.03
SPI1_MISO - F14 - GPIO3_PN.04
SPI1_MOSI - F13 - GPIO3_PN.05
SPI1_CS0# - E14 - GPIO3_PN.06

I am using this pinmux sheet: Jetson Download Center | NVIDIA Developer
And this formula to get the pin number:

  1. calculate the gpio number from the formula: GPIO export value =offset+ (port number* 8 + pin value)

(from here: How do I map signal names to GPIO numbers? - #4 by khaledsalahloudz )

All seems to work fine.
Now, the question is, Can I use the next pins as gpio? How can I get the “GPIO export value”
I can not use the formula with this names (ej. SPI1_SCK) there are not “port_number” or “pin_value” in there.

SPI2_CLK - H14 - SPI1_SCK
SPI2_MISO - H15 - SPI1_DIN
SPI2_MOSI - G15 - SPI1_DOUT
SPI2_CS0# - G16 - SPI1_CS0

Can you help me with some documentation, or something to help me to know if;

Is it possible to use that pins (H14, H15, G15, G16) as gpio?
If possible, can you help me to get the “GPIO export value” to be used in /sys/class/gpio/export for this pins.

Thank you very much!

#3

Have check below macro to figure the gpio value.
…/kernel/kernel-4.9/include/dt-bindings/gpio/tegra186-gpio.h

Check the base by below command

root@nvidia-desktop:/sys# cat /sys/kernel/debug/pinctrl/2430000.pinmux/gpio-ranges
GPIO ranges handled:
0: tegra-gpio GPIOS [320 - 463] PINS [0 - 143]
144: tegra-gpio GPIOS [464 - 471] PINS [152 - 159]
152: tegra-gpio GPIOS [472 - 487] PINS [184 - 199]
168: tegra-gpio GPIOS [488 - 511] PINS [216 - 239]
0: tegra-gpio-aon GPIOS [256 - 263] PINS [144 - 151]
8: tegra-gpio-aon GPIOS [264 - 287] PINS [160 - 183]
32: tegra-gpio-aon GPIOS [288 - 303] PINS [200 - 215]
48: tegra-gpio-aon GPIOS [304 - 319] PINS [240 - 255]

#4

Thank you for your answer.

I am using this macros:

It is working fine with the pins:

SPI1_CLK - G13 - GPIO3_PN.03
SPI1_MISO - F14 - GPIO3_PN.04
SPI1_MOSI - F13 - GPIO3_PN.05
SPI1_CS0# - E14 - GPIO3_PN.06

I am using the “N” macro value:

#define TEGRA186_MAIN_GPIO_PORT_N 13

and 03, 04, 05, 06 as pin_value, and I am using the 320 as offset.

0: tegra-gpio GPIOS [320 - 463] PINS [0 - 143]

And the next formula

GPIO export value =offset+ (port number* 8 + pin value)

All is working fine for that pins.

But, I do not have Idea how to get the gpio value (if it is possible) of the pins:

SPI2_CLK - H14 - SPI1_SCK
SPI2_MISO - H15 - SPI1_DIN
SPI2_MOSI - G15 - SPI1_DOUT
SPI2_CS0# - G16 - SPI1_CS0

Because in the pinmux document: Jetson Download Center | NVIDIA Developer

There is no GPIO3_PX.YY for the SPI2 pins.

Is there an ease way to get gpio numbers for the SPI2 (H14, H15, G15, G16) pins?

Thank you for your time.

#5

Sorry, no other way to get the GPIO number now.

#6

I really appreciate your time.

So, Can not be used the pins (H14, H15, G15, G16) as gpio?

#7

Looks like it’s phx

pinmux.0x0243d018 = 0x00000446; # gpio_wan5_ph0: spi1, pull-down, tristate-disable, input-enable
pinmux.0x0243d010 = 0x00000446; # gpio_wan6_ph1: spi1, pull-down, tristate-disable, input-enable
pinmux.0x0243d008 = 0x00000446; # gpio_wan7_ph2: spi1, pull-down, tristate-disable, input-enable
pinmux.0x0243d000 = 0x0000044a; # gpio_wan8_ph3: spi1, pull-up, tristate-disable, input-enable
1 Like
#8

Sorry, I am new in this, do you mean that I must use phx?:

#define TEGRA186_MAIN_GPIO_PORT_H 7

Port number: 7
pin_value: x

For example, for gpio_wan5_ph0:

GPIO export value =offset + (port number* 8 + pin value)

GPIO export value   = 320 + (7* 8 + 0)  =   376

Is it correct for gpio_wan5_ph0 ?

Thank you very much!

#9

Yes, it’s correct.

1 Like
#10

It is working fine for the pins (H14, H15, G15, G16).

Thank you very much. I appreciate your time!

#11

Hi @ShaneCCC , Now I am trying to modified the pinmux (input/output, initial_value) of the pins. I have no problem modifying the SPI1 pins, but when I try modified the SPI2 pins I do not see the changes when I export the gpios.
I would be very grateful if you could recommend me some readings/tutorials or give me some advice about what could be happening.

I create another topic for that: Problem Modifying tx2 pinmux

Thank you.

#12

Will follow on that topic.

#13