|
|
| Line 1: |
Line 1: |
| <!-- Set release according to "release" parameter in URL and use RELEASE_SUMO_V1.0_DART-MX8M as default
| |
| --> {{INIT_RELEASE_PARAM|RELEASE_SUMO_V1.0_DART-MX8M}}<!--
| |
| --> {{#lst:Yocto_Platform_Customization|{{#var:RELEASE_PARAM}}}} <!--
| |
| --> {{#lst:B2QT_Platform_Customization|{{#var:RELEASE_PARAM}}}} <!--
| |
| --> {{#lst:Android_Platform_Customization|{{#var:RELEASE_PARAM}}}} <!--
| |
| --> {{#lst:Debian_Platform_Customization|{{#var:RELEASE_PARAM}}}} <!--
| |
| --> {{#vardefine: SD_CD_GPIO | 44}} <!--
| |
| --> {{PageHeader|{{#var:HARDWARE_NAME}} GPIO}} {{DocImage|category1=Yocto|category2=Android}}[[Category:Debian]][[Category:{{#var:HARDWARE_NAME}}]] __toc__
| |
|
| |
|
| = GPIO state =
| |
| The current state of the system's GPIOs can be obtained in user space, as shown in the following example:
| |
| {{#switch: {{#var:HARDWARE_NAME}} | DART-MX8M=
| |
| <pre>
| |
| # gpioinfo
| |
| gpiochip0: GPIOs 0-31, parent: platform/30200000.gpio, 30200000.gpio:
| |
| gpio-8 ( |eth_phy_pwr ) out hi
| |
| gpio-9 ( |phy-reset ) out hi
| |
| gpio-10 ( |connect ) in hi IRQ
| |
|
| |
| gpiochip1: GPIOs 32-63, parent: platform/30210000.gpio, 30210000.gpio:
| |
| gpio-44 ( |cd ) in lo IRQ
| |
| gpio-51 ( |VSD_3V3 ) out hi
| |
|
| |
| gpiochip2: GPIOs 64-95, parent: platform/30220000.gpio, 30220000.gpio:
| |
|
| |
| gpiochip3: GPIOs 96-127, parent: platform/30230000.gpio, 30230000.gpio:
| |
| gpio-102 ( |Back ) in hi IRQ
| |
| gpio-109 ( |Home ) in hi IRQ
| |
| gpio-111 ( |Down ) in hi IRQ
| |
| gpio-113 ( |? ) out lo
| |
| gpio-114 ( |Up ) in hi IRQ
| |
| </pre>
| |
| | DART-MX8M-MINI=
| |
| <pre>
| |
| # gpioinfo
| |
| gpiochip0: GPIOs 0-31, parent: platform/30200000.gpio, 30200000.gpio:
| |
| gpio-7 ( |eth_phy_pwr ) out lo
| |
| gpio-9 ( |phy-reset ) out hi
| |
|
| |
| gpiochip1: GPIOs 32-63, parent: platform/30210000.gpio, 30210000.gpio:
| |
| gpio-38 ( |sysfs ) out hi
| |
| gpio-39 ( |sysfs ) out hi
| |
| gpio-42 ( |sysfs ) out hi
| |
| gpio-43 ( |enable ) out hi
| |
| gpio-44 ( |cd ) in lo IRQ
| |
| gpio-51 ( |VSD_3V3 ) out hi
| |
| gpio-52 ( |sysfs ) out lo
| |
|
| |
| gpiochip2: GPIOs 64-95, parent: platform/30220000.gpio, 30220000.gpio:
| |
|
| |
| gpiochip3: GPIOs 96-127, parent: platform/30230000.gpio, 30230000.gpio:
| |
| gpio-102 ( |Back ) in hi IRQ
| |
| gpio-104 ( |ov5640_mipi_pwdn ) out lo
| |
| gpio-109 ( |Home ) in hi IRQ
| |
| gpio-111 ( |Down ) in hi IRQ
| |
| gpio-113 ( |eMMC ) out lo
| |
| gpio-114 ( |Up ) in hi IRQ
| |
|
| |
| gpiochip4: GPIOs 128-159, parent: platform/30240000.gpio, 30240000.gpio:
| |
| gpio-133 ( |sysfs ) out lo
| |
| gpio-137 ( |spi_imx ) in lo
| |
| gpio-156 ( |ov5640_mipi_reset ) out hi
| |
| </pre>
| |
| | VAR-SOM-MX8M-NANO=
| |
| <pre>
| |
| # gpioinfo
| |
| gpiochip0: GPIOs 0-31, parent: platform/30200000.gpio, 30200000.gpio:
| |
| gpio-0 ( |spi_imx ) out hi
| |
| gpio-9 ( |phy-reset ) out hi
| |
| gpio-10 ( |connect ) in hi IRQ
| |
| gpio-13 ( |ov5640_mipi_reset ) out hi
| |
| gpio-14 ( |spi_imx ) in lo
| |
|
| |
| gpiochip1: GPIOs 32-63, parent: platform/30210000.gpio, 30210000.gpio:
| |
| gpio-38 ( |sysfs ) out hi
| |
| gpio-39 ( |sysfs ) out hi
| |
| gpio-41 ( |eth_phy_pwr ) out hi
| |
| gpio-42 ( |sysfs ) out hi
| |
| gpio-43 ( |enable ) out hi
| |
| gpio-44 ( |cd ) in lo IRQ
| |
| gpio-51 ( |VSD_3V3 ) out hi
| |
| gpio-52 ( |sysfs ) out hi
| |
|
| |
| gpiochip2: GPIOs 64-95, parent: platform/30220000.gpio, 30220000.gpio:
| |
|
| |
| gpiochip3: GPIOs 96-127, parent: platform/30230000.gpio, 30230000.gpio:
| |
|
| |
| gpiochip4: GPIOs 128-159, parent: platform/30240000.gpio, 30240000.gpio:
| |
| gpio-133 ( |sysfs ) out lo
| |
| gpio-140 ( |ov5640_mipi_pwdn ) out lo
| |
|
| |
| gpiochip6: GPIOs 502-503, parent: spi/spi0.1, spi0.1, can sleep:
| |
|
| |
| gpiochip5: GPIOs 504-511, parent: i2c/1-0020, pca9534, can sleep:
| |
| gpio-504 ( |Heartbeat ) out lo
| |
| gpio-505 ( |Back ) in hi IRQ
| |
| gpio-506 ( |Home ) in hi IRQ
| |
| gpio-507 ( |Menu ) in hi IRQ
| |
| gpio-508 ( |usb3_sel ) out hi
| |
| gpio-509 ( |enet_rst ) out lo
| |
| gpio-510 ( |som_vsel ) out lo
| |
| gpio-511 ( |enet_sel ) out lo
| |
| </pre>
| |
| | DART-MX8M-PLUS=
| |
| <pre>
| |
| # gpioinfo
| |
| gpiochip0: GPIOs 0-31, parent: platform/30200000.gpio, 30200000.gpio:
| |
| gpio-5 ( |hdmi_on ) out lo
| |
| gpio-7 ( |ads7846_pendown ) in hi IRQ
| |
| gpio-10 ( |int ) in hi IRQ
| |
| gpio-12 ( |spi_imx ) out hi
| |
|
| |
| gpiochip1: GPIOs 32-63, parent: platform/30210000.gpio, 30210000.gpio:
| |
| gpio-38 ( |sysfs ) out hi
| |
| gpio-39 ( |sysfs ) out hi
| |
| gpio-40 ( |sysfs ) out hi
| |
| gpio-41 ( |sysfs ) out lo
| |
| gpio-42 ( |spi_imx ) out hi
| |
| gpio-44 ( |cd ) in lo IRQ ACTIVE LOW
| |
| gpio-51 ( |regulator-usdhc2-vmm) out hi
| |
| gpio-52 ( |regulator-eqos-phy-p) out hi
| |
|
| |
| gpiochip2: GPIOs 64-95, parent: platform/30220000.gpio, 30220000.gpio:
| |
|
| |
| gpiochip3: GPIOs 96-127, parent: platform/30230000.gpio, 30230000.gpio:
| |
| gpio-101 ( |reset ) out hi ACTIVE LOW
| |
| gpio-102 ( |Back ) in hi IRQ ACTIVE LOW
| |
| gpio-104 ( |powerdown ) out hi
| |
| gpio-105 ( |powerdown ) out hi
| |
| gpio-108 ( |reset ) out hi ACTIVE LOW
| |
| gpio-109 ( |Home ) in hi IRQ ACTIVE LOW
| |
| gpio-111 ( |Down ) in hi IRQ ACTIVE LOW
| |
| gpio-113 ( |eMMC ) out lo
| |
| gpio-114 ( |Up ) in hi IRQ ACTIVE LOW
| |
|
| |
| gpiochip4: GPIOs 128-159, parent: platform/30240000.gpio, 30240000.gpio:
| |
| gpio-137 ( |spi_imx ) out hi
| |
| gpio-142 ( |scl ) out lo
| |
| gpio-143 ( |sda ) in lo
| |
| gpio-144 ( |scl ) out lo
| |
| gpio-145 ( |sda ) in lo
| |
| gpio-146 ( |scl ) out lo
| |
| gpio-147 ( |sda ) in lo
| |
| gpio-148 ( |scl ) out lo
| |
| gpio-149 ( |sda ) in lo
| |
| gpio-156 ( |reset ) out hi ACTIVE LOW
| |
| </pre>
| |
| | VAR-SOM-MX93=
| |
| <pre>
| |
| # gpioinfo
| |
| gpiochip3: GPIOs 0-31, parent: platform/47400080.gpio, 47400080.gpio:
| |
| gpio-0 ( |spi0 CS0 ) out hi ACTIVE LOW
| |
| gpio-1 ( |sda ) in lo
| |
| gpio-7 ( |regulator-eqos-phy ) out hi
| |
|
| |
| gpiochip0: GPIOs 32-63, parent: platform/43810080.gpio, 43810080.gpio:
| |
| gpio-43 ( |powerdown ) out hi
| |
| gpio-44 ( |spi1 CS0 ) out hi ACTIVE LOW
| |
| gpio-49 ( |cam_buf_dis ) in lo
| |
| gpio-50 ( |regulator-usdhc2 ) out hi
| |
| gpio-54 ( |sda ) in lo
| |
| gpio-55 ( |scl ) out lo
| |
| gpio-60 ( |sda ) in lo
| |
| gpio-61 ( |scl ) out lo
| |
|
| |
| gpiochip1: GPIOs 64-95, parent: platform/43820080.gpio, 43820080.gpio:
| |
| gpio-64 ( |cd ) in lo IRQ ACTIVE LOW
| |
| gpio-71 ( |regulator-usdhc3 ) out hi
| |
| gpio-91 ( |reset ) out hi ACTIVE LOW
| |
|
| |
| gpiochip2: GPIOs 96-127, parent: platform/43830080.gpio, 43830080.gpio:
| |
| gpio-110 ( |regulator-wl-on ) out hi
| |
|
| |
| gpiochip4: GPIOs 504-511, parent: i2c/4-0020, 4-0020, can sleep:
| |
| gpio-505 ( |Back ) in hi IRQ ACTIVE LOW
| |
| gpio-506 ( |Home ) in hi IRQ ACTIVE LOW
| |
| gpio-507 ( |Menu ) in hi IRQ ACTIVE LOW
| |
| gpio-509 ( |regulator-fec-phy-rs) out hi
| |
| gpio-510 ( |regulator-fec-phy-vs) out hi
| |
| gpio-511 ( |regulator-fec-phy ) out hi
| |
| </pre>
| |
| {{#vardefine: SD_CD_GPIO | 64}} }}
| |
|
| |
| Each GPIO is defined as in or out and the state is shown as lo or hi.<br>
| |
| For example, pin {{#var: SD_CD_GPIO}} is the SD card card-detect.
| |
| When an SD card is plugged in, the state will be:
| |
| gpio-{{#var: SD_CD_GPIO}} ( |cd ) in lo IRQ
| |
| When the SD card is removed, the state will be:
| |
| gpio-{{#var: SD_CD_GPIO}} ( |cd ) in hi IRQ
| |
|
| |
| = Manipulating GPIO using libgpiod =
| |
| {{#vardefine:LIBGPIOD_URL|https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/}}<!--
| |
| -->The Linux GPIO sysfs interface is being deprecated. Moving forward, user space should use the character device <code>/dev/gpiochip*</code> instead. libgpiod provides bindings and utilities for manipulating GPIO via user space.
| |
|
| |
| == libgpiod via command line ==
| |
|
| |
| [{{#var:LIBGPIOD_URL}} libgpiod] provides command line utilities for GPIO:
| |
|
| |
| {| class="wikitable"
| |
| |-
| |
| | '''gpiodetect'''
| |
| | List all gpiochips present on the system, their names, labels, and number of GPIO lines.
| |
| |-
| |
| | '''gpioinfo'''
| |
| | List all lines of specified gpiochips, their names, consumers, direction, active state, and additional flags.
| |
| |-
| |
| | '''gpioget'''
| |
| | Read the values of the specified GPIO lines (not valid if the line is already requested). The line will be then configured as input.
| |
| |-
| |
| | '''gpioset'''
| |
| | Set the values of the specified GPIO lines, potentially keeping the lines exported, and wait until timeout, user input, or signal (not valid if the line is already requested). The line will be then configured as output.
| |
| |-
| |
| | '''gpiofind'''
| |
| | Find the gpiochip name and line offset given the line name.
| |
| |-
| |
| | '''gpiomon'''
| |
| | Wait for events on GPIO lines, specify which events to watch, how many events to process before exiting, or if the events should be reported to the console.
| |
| |}
| |
|
| |
| i.MX GPIOs are organized in banks of 32 pins. Each bank corresponds to a character device <code>/dev/gpiochip<bank index></code>. The <code>gpiodetect</code> utility can be used to inspect the available gpiochip character devices:
| |
|
| |
| # gpiodetect
| |
| gpiochip0 [30200000.gpio] (32 lines)
| |
| gpiochip1 [30210000.gpio] (32 lines)
| |
| ...
| |
|
| |
| The <code>gpioinfo</code> utility can be used to inspect the lines for a given gpiochip:
| |
|
| |
| # gpioinfo gpiochip0
| |
| gpiochip0 - 32 lines:
| |
| line 0: unnamed "spi_imx" output active-high [used]
| |
| line 1: unnamed unused input active-high
| |
| line 2: unnamed unused input active-high
| |
| ...
| |
|
| |
| The <code>gpioset</code> and <code>gpioget</code> utilities can be used to manipulate GPIO from the command line.<br>
| |
|
| |
| For example, assuming GPIO4_21 is configured as a GPIO in your device tree:
| |
|
| |
| Set GPIO4_21 high:
| |
| gpioset gpiochip3 21=1
| |
|
| |
| Set GPIO4_21 low:
| |
| gpioset gpiochip3 21=0
| |
|
| |
| Read GPIO4_21:
| |
| gpioget gpiochip3 21
| |
|
| |
| The <code>gpiomon</code> utility is useful for polling the lines to expect incoming input events.<br>
| |
| For example, wait for three rising edge events on a given GPIO line:
| |
| gpiomon --num-events=3 --rising-edge gpiochip3 21
| |
| event: RISING EDGE offset: 3 timestamp: [ 1151.814356387]
| |
| event: RISING EDGE offset: 3 timestamp: [ 1151.815449803]
| |
| event: RISING EDGE offset: 3 timestamp: [ 1152.091556803]
| |
|
| |
| == libgpiod C Application ==
| |
|
| |
| [{{#var:LIBGPIOD_URL}} libgpiod] provides bindings for C/C++ applications. C++ examples are available in the libgpiod [{{#var:LIBGPIOD_URL}}/tree/bindings/cxx/examples /tree/bindings/cxx/examples ] directory.
| |
|
| |
| Below is a simple C application demonstrating how to use the bindings with GPIO4_IO21:
| |
|
| |
| '''Makefile:'''
| |
| all: main.cpp
| |
| $(CC) $(CCFLAGS) -Og -lgpiod main.c -g -o hello.bin
| |
| clean:
| |
| rm -f hello.bin
| |
|
| |
| '''main.c'''
| |
| <pre>
| |
| #include <gpiod.h>
| |
| #include <stdio.h>
| |
| #include <unistd.h>
| |
| #include <stdlib.h>
| |
| #include <string.h>
| |
|
| |
| #define CONSUMER "Variscite Demo"
| |
|
| |
| int main(int argc, char **argv)
| |
| {
| |
| unsigned int i, ret, val;
| |
| struct gpiod_chip *chip;
| |
| struct gpiod_line *line;
| |
| const char * chipname = "gpiochip3";
| |
| const unsigned int line_num = 21;
| |
|
| |
| chip = gpiod_chip_open_by_name(chipname);
| |
| if (!chip) {
| |
| perror("Open chip failed\n");
| |
| goto end;
| |
| }
| |
|
| |
| line = gpiod_chip_get_line(chip, line_num);
| |
| if (!line) {
| |
| perror("Get line failed\n");
| |
| goto close_chip;
| |
| }
| |
|
| |
| ret = gpiod_line_request_output(line, CONSUMER, 0);
| |
| if (ret < 0) {
| |
| perror("Request line as output failed\n");
| |
| goto release_line;
| |
| }
| |
|
| |
| /* Blink 5 times */
| |
| val = 0;
| |
| for (i = 0; i < 5; i++) {
| |
| ret = gpiod_line_set_value(line, val);
| |
| if (ret < 0) {
| |
| perror("Set line output failed\n");
| |
| goto release_line;
| |
| }
| |
| printf("Output %u on line #%u\n", val, line_num);
| |
| sleep(1);
| |
| val = !val;
| |
| }
| |
|
| |
| release_line:
| |
| gpiod_line_release(line);
| |
| close_chip:
| |
| gpiod_chip_close(chip);
| |
| end:
| |
| return 0;
| |
| }
| |
| </pre>
| |
|
| |
| == libgpiod Python Application ==
| |
|
| |
| libgpiod provides bindings for python applications:
| |
|
| |
| # pip3 install gpiod
| |
|
| |
| Python examples are available in the libgpiod [{{#var:LIBGPIOD_URL}}/tree/bindings/python/examples /tree/bindings/python/examples ] directory.
| |