MX8M GPIO: Difference between revisions
No edit summary |
|||
(55 intermediate revisions by 8 users not shown) | |||
Line 1: | Line 1: | ||
<!-- Set release according to "release" parameter in URL and use RELEASE_SUMO_V1.0_DART-MX8M as default | <!-- 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: | --> {{#lst:Yocto_Platform_Customization|{{#var:RELEASE_PARAM}}}} <!-- | ||
--> {{PageHeader|{{#var:HARDWARE_NAME}} GPIO}} {{DocImage|category1=Yocto|category2=Android}}[[Category: | --> {{#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 = | = GPIO state = | ||
The current state of the system's GPIOs can be obtained in user-mode, as shown in the following example: | The current state of the system's GPIOs can be obtained in user-mode, as shown in the following example: | ||
{{# | {{#switch: {{#var:HARDWARE_NAME}} | DART-MX8M= | ||
<pre> | <pre> | ||
# cat /sys/kernel/debug/gpio | # cat /sys/kernel/debug/gpio | ||
Line 27: | Line 31: | ||
gpio-114 ( |Up ) in hi IRQ | gpio-114 ( |Up ) in hi IRQ | ||
</pre> | </pre> | ||
| | | DART-MX8M-MINI= | ||
<pre> | <pre> | ||
# cat /sys/kernel/debug/gpio | # cat /sys/kernel/debug/gpio | ||
Line 58: | Line 62: | ||
gpio-156 ( |ov5640_mipi_reset ) out hi | gpio-156 ( |ov5640_mipi_reset ) out hi | ||
</pre> | </pre> | ||
| VAR-SOM-MX8M-NANO= | |||
<pre> | |||
# cat /sys/kernel/debug/gpio | |||
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> | |||
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> | |||
# cat /sys/kernel/debug/gpio | |||
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> | |||
| DART-MX95= | |||
<pre> | |||
root@imx95-var-dart:~# cat /sys/kernel/debug/gpio | |||
gpiochip0: GPIOs 512-543, parent: platform/43810000.gpio, 43810000.gpio: | |||
gpio-516 ( |spi0 CS0 ) out hi ACTIVE LOW | |||
gpio-522 ( |scl ) out lo | |||
gpio-523 ( |sda ) in lo | |||
gpio-534 ( |microchip,rx-int ) in hi ACTIVE LOW | |||
gpio-536 ( |pendown ) in hi IRQ ACTIVE LOW | |||
gpio-539 ( |reset ) out hi ACTIVE LOW | |||
gpio-540 ( |scl ) out lo | |||
gpio-541 ( |sda ) in lo | |||
gpiochip1: GPIOs 544-575, parent: platform/43820000.gpio, 43820000.gpio: | |||
gpio-544 ( |cd ) in lo IRQ ACTIVE LOW | |||
gpio-551 ( |regulator-usdhc2 ) out hi | |||
gpio-571 ( |Heartbeat ) out lo | |||
gpiochip2: GPIOs 576-607, parent: platform/43840000.gpio, 43840000.gpio: | |||
gpio-605 ( |reset ) out hi ACTIVE LOW | |||
gpiochip3: GPIOs 608-639, parent: platform/43850000.gpio, 43850000.gpio: | |||
gpio-612 ( |spi0 CS2 ) out hi ACTIVE LOW | |||
gpio-621 ( |spi0 CS1 ) out hi ACTIVE LOW | |||
gpio-622 ( |int ) in hi IRQ | |||
gpio-624 ( |regulator-enet0-phy ) out hi | |||
gpiochip4: GPIOs 640-671, parent: platform/47400000.gpio, 47400000.gpio: | |||
gpiochip5: GPIOs 672-679, parent: i2c/7-0020, 7-0020, can sleep: | |||
gpio-673 ( |reset ) out hi ACTIVE LOW | |||
gpio-675 ( |powerdown ) out hi | |||
gpio-676 ( |Home ) in hi IRQ ACTIVE LOW | |||
gpio-677 ( |Up ) in hi IRQ ACTIVE LOW | |||
gpio-678 ( |Down ) in hi IRQ ACTIVE LOW | |||
gpio-679 ( |Back ) in hi IRQ ACTIVE LOW | |||
gpiochip6: GPIOs 680-687, parent: i2c/7-0021, 7-0021, can sleep: | |||
gpio-680 ( |regulator-enet1-phy ) out hi | |||
gpio-683 ( |PCIe reset ) out hi | |||
gpio-684 ( |reset ) out hi ACTIVE LOW | |||
</pre> | |||
{{#vardefine: SD_CD_GPIO | 64}} | |||
}} | }} | ||
Each GPIO is defined as in or out and the state is shown as lo or hi.<br> | Each GPIO is defined as in or out and the state is shown as lo or hi.<br> | ||
For example pin | For example pin {{#var: SD_CD_GPIO}} is the SD card card-detect. | ||
When an SD card is plugged in, the state will be: | When an SD card is plugged in, the state will be: | ||
gpio-{{#var: SD_CD_GPIO}} ( |cd ) in lo IRQ | |||
gpio- | |||
When the SD card is removed, the state will be: | When the SD card is removed, the state will be: | ||
gpio-{{#var: SD_CD_GPIO}} ( |cd ) in hi IRQ | |||
= Manipulating GPIO using libgpiod = | |||
<section begin=libgpiod_section/><!-- | |||
-->{{#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 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 values of specified GPIO lines | |||
|- | |||
| '''gpioset''' | |||
| Set values of specified GPIO lines, potentially keep the lines exported and wait until timeout, user input or signal | |||
|- | |||
| '''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. | |||
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 | |||
== 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> | <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> | </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. | |||
<section end=libgpiod_section/> | |||
<!-- Start to phase out sysfs by hiding it for imx9 and future SOC_FAMILY. Eventually, drop this for all families | |||
-->{{#switch:{{#var:SOC_FAMILY}} | |||
|imx8m= | |||
= Manipulating a single GPIO via /sys/class/gpio = | = Manipulating a single GPIO via /sys/class/gpio = | ||
<section begin=gpio_sysfs_warning_section/> <!-- | |||
-->{{Note|Note: The /sys/class/gpio ABI is being deprecated in the Linux kernel and is being replaced by the GPIO character device and [{{#var:LIBGPIOD_URL}} libgpiod]. Please refer to the kernel [https://github.com/varigit/linux-imx/blob/{{#var:KERNEL_BRANCH}}/Documentation/ABI/obsolete/sysfs-gpio Documentation] for the latest information.|error}}<!-- | |||
--><section end=gpio_sysfs_warning_section/> | |||
== Using a command line or a script == | == Using a command line or a script == | ||
GPIOs in i.MX are grouped in groups of 32 pins.<br> | GPIOs in i.MX are grouped in groups of 32 pins.<br> | ||
Line 192: | Line 498: | ||
</pre> | </pre> | ||
* This is only a short example. If you want to use it in your code remember add error handling to it. | * This is only a short example. If you want to use it in your code remember add error handling to it. | ||
}}<!-- END OF SYSFS --> | |||
= Kernel Device Tree GPIO configuration = | = Kernel Device Tree GPIO configuration = | ||
== Device Tree GPIO files == | == Device Tree GPIO files == | ||
=== Pin Func files === | === Pin Func files === | ||
{{# | {{#switch: {{#var:HARDWARE_NAME}} | DART-MX8M= | ||
In the directory {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}} | In the directory {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale of the Linux kernel source you will find the pin functions definition files.<br> | ||
The relevant file is | The relevant file is imx8mq-pinfunc.h.<br> | ||
If you search it for GPIO4_IO2, for example, you will see a group of definitions with same prefix (pad name), "MX8MQ_IOMUXC_SAI1_RXD0". | If you search it for GPIO4_IO2, for example, you will see a group of definitions with same prefix (pad name), "MX8MQ_IOMUXC_SAI1_RXD0". | ||
<pre> | <pre> | ||
Line 208: | Line 515: | ||
#define MX8MQ_IOMUXC_SAI1_RXD0_SIM_M_HADDR17 0x164 0x3CC 0x000 0x7 0x0 | #define MX8MQ_IOMUXC_SAI1_RXD0_SIM_M_HADDR17 0x164 0x3CC 0x000 0x7 0x0 | ||
</pre> | </pre> | ||
| | | DART-MX8M-MINI= | ||
In the directory {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}} | In the directory {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale of the Linux kernel source you will find the pin functions definition files.<br> | ||
The relevant file is | The relevant file is imx8mm-pinfunc.h.<br> | ||
If you search it for GPIO4_IO2, for example, you will see a group of definitions with same prefix (pad name), "MX8MM_IOMUXC_SAI1_RXD0". | If you search it for GPIO4_IO2, for example, you will see a group of definitions with same prefix (pad name), "MX8MM_IOMUXC_SAI1_RXD0". | ||
<pre> | <pre> | ||
Line 220: | Line 527: | ||
#define MX8MM_IOMUXC_SAI1_RXD0_CCMSRCGPCMIX_BOOT_CFG0 0x164 0x3CC 0x000 0x6 0x0 | #define MX8MM_IOMUXC_SAI1_RXD0_CCMSRCGPCMIX_BOOT_CFG0 0x164 0x3CC 0x000 0x6 0x0 | ||
#define MX8MM_IOMUXC_SAI1_RXD0_SIM_M_HADDR17 0x164 0x3CC 0x000 0x7 0x0 | #define MX8MM_IOMUXC_SAI1_RXD0_SIM_M_HADDR17 0x164 0x3CC 0x000 0x7 0x0 | ||
</pre> | |||
| VAR-SOM-MX8M-NANO= | |||
In the directory {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale of the Linux kernel source you will find the pin functions definition files.<br> | |||
The relevant file is imx8mn-pinfunc.h.<br> | |||
If you search it for GPIO4_IO22, for example, you will see a group of definitions with same prefix (pad name), "MX8MN_IOMUXC_SAI2_RXC". | |||
<pre> | |||
#define MX8MN_IOMUXC_SAI2_RXC_SAI2_RX_BCLK 0x01B4 0x041C 0x0000 0x0 0x0 | |||
#define MX8MN_IOMUXC_SAI2_RXC_SAI5_TX_BCLK 0x01B4 0x041C 0x04E8 0x1 0x2 | |||
#define MX8MN_IOMUXC_SAI2_RXC_UART1_DCE_RX 0x01B4 0x041C 0x04F4 0x4 0x3 | |||
#define MX8MN_IOMUXC_SAI2_RXC_UART1_DTE_TX 0x01B4 0x041C 0x0000 0x4 0x0 | |||
#define MX8MN_IOMUXC_SAI2_RXC_GPIO4_IO22 0x01B4 0x041C 0x0000 0x5 0x0 | |||
#define MX8MN_IOMUXC_SAI2_RXC_PDM_BIT_STREAM1 0x01B4 0x041C 0x0538 0x6 0x8 | |||
</pre> | |||
| DART-MX8M-PLUS= | |||
In the directory {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale of the Linux kernel source you will find the pin functions definition files.<br> | |||
The relevant file is imx8mp-pinfunc.h.<br> | |||
If you search it for GPIO4_IO22, for example, you will see a group of definitions with same prefix (pad name), "MX8MP_IOMUXC_SAI2_RXC". | |||
<pre> | |||
#define MX8MP_IOMUXC_SAI2_RXC__AUDIOMIX_SAI2_RX_BCLK 0x1A0 0x400 0x000 0x0 0x0 | |||
#define MX8MP_IOMUXC_SAI2_RXC__AUDIOMIX_SAI5_TX_BCLK 0x1A0 0x400 0x50C 0x1 0x2 | |||
#define MX8MP_IOMUXC_SAI2_RXC__CAN1_TX 0x1A0 0x400 0x000 0x3 0x0 | |||
#define MX8MP_IOMUXC_SAI2_RXC__UART1_DCE_RX 0x1A0 0x400 0x5E8 0x4 0x3 | |||
#define MX8MP_IOMUXC_SAI2_RXC__UART1_DTE_TX 0x1A0 0x400 0x000 0x4 0x0 | |||
#define MX8MP_IOMUXC_SAI2_RXC__GPIO4_IO22 0x1A0 0x400 0x000 0x5 0x0 | |||
#define MX8MP_IOMUXC_SAI2_RXC__AUDIOMIX_PDM_BIT_STREAM01 0x1A0 0x400 0x4C4 0x6 0x5 | |||
</pre> | |||
| VAR-SOM-MX93= | |||
In the directory arch/arm64/boot/dts/freescale of the Linux kernel source you will find the pin functions definition files.<br> | |||
The relevant file is imx93-pinfunc.h.<br> | |||
If you search it for GPIO_IO25, for example, you will see a group of definitions with same prefix (pad name), "MX93_PAD_GPIO_IO25". | |||
<pre> | |||
#define MX93_PAD_GPIO_IO25__GPIO2_IO25 0x0074 0x0224 0x0000 0x0 0x0 | |||
#define MX93_PAD_GPIO_IO25__USDHC3_DATA1 0x0074 0x0224 0x0464 0x1 0x0 | |||
#define MX93_PAD_GPIO_IO25__CAN2_TX 0x0074 0x0224 0x0000 0x2 0x0 | |||
#define MX93_PAD_GPIO_IO25__MEDIAMIX_DISP_DATA21 0x0074 0x0224 0x0000 0x3 0x0 | |||
#define MX93_PAD_GPIO_IO25__TPM4_CH3 0x0074 0x0224 0x0000 0x4 0x0 | |||
#define MX93_PAD_GPIO_IO25__JTAG_MUX_TCK 0x0074 0x0224 0x03D4 0x5 0x1 | |||
#define MX93_PAD_GPIO_IO25__LPSPI7_PCS1 0x0074 0x0224 0x0000 0x6 0x0 | |||
#define MX93_PAD_GPIO_IO25__FLEXIO1_FLEXIO25 0x0074 0x0224 0x03C4 0x7 0x0 | |||
</pre> | </pre> | ||
}} | }} | ||
Adding only the one with the GPIO4_IO2 suffix (function) to your dts file will let you use the pin as GPIO. | Adding only the one with the {{#switch: {{#var:HARDWARE_NAME}}|VAR-SOM-MX8M-NANO|DART-MX8M-PLUS=GPIO4_IO22|VAR-SOM-MX93=GPIO_IO25|GPIO4_IO2}} suffix (function) to your dts file will let you use the pin as GPIO. | ||
== Define a pin as GPIO in the kernel Device Tree == | == Define a pin as GPIO in the kernel Device Tree == | ||
You need to add the relevant definitions to your device tree, as explained in the [[#Pin Func files|Pin Func files]] section above.<br> | You need to add the relevant definitions to your device tree, as explained in the [[#Pin Func files|Pin Func files]] section above.<br> | ||
{{# | {{#switch: {{#var:HARDWARE_NAME}} | DART-MX8M= | ||
Edit arch/arm64/boot/dts/{{#ifeq: {{#var:YOCTO_NAME}} | Morty |variscite/imx8m-var-dart-common.dtsi|freescale/fsl-imx8mq-var-dart-common.dtsi}} and add the definition for the GPIO you need in the iomuxc node.<br> | Edit {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/{{#ifeq: {{#var:YOCTO_NAME}} | Morty |variscite/imx8m-var-dart-common.dtsi|freescale/{{#var:DTB_PREFIX|fsl-imx8mq-var-dart}}{{#ifeq: {{#sub:{{#var:KERNEL_VER}}|0|2}} | 4. | -common | }}.dtsi}} and add the definition for the GPIO you need in the iomuxc node.<br> | ||
<pre> | <pre> | ||
&iomuxc { | &iomuxc { | ||
Line 240: | Line 587: | ||
}; | }; | ||
}; | }; | ||
… | |||
}; | }; | ||
</pre> | </pre> | ||
| | | DART-MX8M-MINI= | ||
Edit arch/arm64/boot/dts/freescale/fsl-imx8mm-var-dart.dts and add the definition for the GPIO you need in the iomuxc node.<br> | Edit {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale/{{#var:DTB_PREFIX|fsl-imx8mm-var-dart}}.dts and add the definition for the GPIO you need in the iomuxc node.<br> | ||
<pre> | <pre> | ||
&iomuxc { | &iomuxc { | ||
Line 257: | Line 604: | ||
}; | }; | ||
}; | }; | ||
… | |||
}; | |||
</pre> | |||
| VAR-SOM-MX8M-NANO= | |||
Edit {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale/{{#var:DTB_PREFIX|fsl-imx8mn-var-som}}.dts and add the definition for the GPIO you need in the iomuxc node.<br> | |||
<pre> | |||
&iomuxc { | |||
pinctrl-names = "default"; | |||
pinctrl-0 = <&pinctrl_hog>; | |||
imx8mn-var-som { | |||
pinctrl_hog: hoggrp { | |||
fsl,pins = < | |||
/* Add your GPIO definitions here */ | |||
>; | |||
}; | |||
}; | |||
… | |||
}; | |||
</pre> | |||
| DART-MX8M-PLUS= | |||
Edit {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/freescale/imx8mp-var-dart.dts and add the definition for the GPIO you need in the iomuxc node.<br> | |||
<pre> | |||
&iomuxc { | |||
pinctrl-names = "default"; | |||
pinctrl-0 = <&pinctrl_hog>; | |||
pinctrl_hog: hoggrp { | |||
fsl,pins = < | |||
/* Add your GPIO definitions here */ | |||
>; | |||
}; | |||
… | |||
}; | |||
</pre> | |||
| VAR-SOM-MX93= | |||
Edit arch/arm64/boot/dts/freescale/imx93-var-som-symphony.dts and add the definition for the GPIO you need in the iomuxc node.<br> | |||
<pre> | |||
&iomuxc { | |||
pinctrl-names = "default"; | |||
pinctrl-0 = <&pinctrl_hog>; | |||
pinctrl_hog: hoggrp { | |||
fsl,pins = < | |||
/* Add your GPIO definitions here */ | |||
>; | |||
}; | |||
… | |||
}; | }; | ||
</pre> | </pre> | ||
Line 263: | Line 657: | ||
=== Device Tree GPIO attribute === | === Device Tree GPIO attribute === | ||
If you look at the pin control definitions in arch/arm64/boot/dts/{{#ifeq: {{#var:HARDWARE_NAME}} | DART-MX8M |{{#ifeq: {{#var:YOCTO_NAME}} | Morty |variscite/imx8m-var-dart-common.dtsi|freescale/fsl-imx8mq-var-dart-common.dtsi}}| freescale/fsl-imx8mm-var-dart.dts}} in the Linux kernel source tree, the number to the right of the pin mux macro can be used for additional attributes like pull-up, slew rate, open drain, drive strength, etc.<br> | If you look at the pin control definitions in {{#ifeq: {{#var:ANDROID_NAME}} | Pie |{{#var:BUILD_FOLDER}}/{{#var:BUILD_FOLDER_ANDROID}}/variscite/kernel_imx/}}arch/arm64/boot/dts/{{#ifeq: {{#var:HARDWARE_NAME}} | DART-MX8M |{{#ifeq: {{#var:YOCTO_NAME}} | Morty |variscite/imx8m-var-dart-common.dtsi|freescale/{{#var:DTB_PREFIX|fsl-imx8mq-var-dart}}{{#ifeq: {{#sub:{{#var:KERNEL_VER}}|0|2}} | 4. | -common | }}.dtsi}}| {{#ifeq: {{#var:HARDWARE_NAME}} | DART-MX8M-MINI |freescale/{{#var:DTB_PREFIX|fsl-imx8mm-var-dart}}.dts | {{#ifeq: {{#var:HARDWARE_NAME}} | VAR-SOM-MX8M-NANO |freescale/{{#var:DTB_PREFIX|fsl-imx8mn-var-som}}.dts | {{#ifeq: {{#var:HARDWARE_NAME}} | DART-MX8M-PLUS |freescale/imx8mp-var-dart.dts}}}}}}}} in the Linux kernel source tree, the number to the right of the pin mux macro can be used for additional attributes like pull-up, slew rate, open drain, drive strength, etc.<br> | ||
This value is written to the IOMUXC_SW_PAD_CTRL_ register of the relevant pin.<br> | This value is written to the IOMUXC_SW_PAD_CTRL_ register of the relevant pin.<br> | ||
Please consult the SOC reference manual for details about the relevant register. | Please consult the SOC reference manual for details about the relevant register. |
Latest revision as of 12:18, 23 October 2024
This page is using the default release RELEASE_SUMO_V1.0_DART-MX8M.
To view this page for a specific Variscite SoM and software release, please follow these steps:
- Visit variwiki.com
- Select your SoM
- Select the software release
GPIO state
The current state of the system's GPIOs can be obtained in user-mode, as shown in the following example:
# cat /sys/kernel/debug/gpio 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
Each GPIO is defined as in or out and the state is shown as lo or hi.
For example pin 44 is the SD card card-detect.
When an SD card is plugged in, the state will be:
gpio-44 ( |cd ) in lo IRQ
When the SD card is removed, the state will be:
gpio-44 ( |cd ) in hi IRQ
Manipulating GPIO using libgpiod
The Linux GPIO sysfs interface is being deprecated. Moving forward, user space should use the character device /dev/gpiochip*
instead. libgpiod provides bindings and utilities for for manipulating GPIO via user space.
libgpiod via command line
libgpiod provides command line utilities for GPIO:
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 values of specified GPIO lines |
gpioset | Set values of specified GPIO lines, potentially keep the lines exported and wait until timeout, user input or signal |
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 /dev/gpiochip<bank index>
. The gpiodetect
utility can be used to inspect the available gpiochip character devices:
# gpiodetect gpiochip0 [30200000.gpio] (32 lines) gpiochip1 [30210000.gpio] (32 lines) ...
The gpioinfo
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 gpioset
and gpioget
utilities can be used to manipulate GPIO from the command line.
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
libgpiod C Application
libgpiod provides bindings for C/C++ applications. C++ examples are available in the libgpiod /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
#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; }
libgpiod Python Application
libgpiod provides bindings for python applications:
# pip3 install gpiod
Python examples are available in the libgpiod /tree/bindings/python/examples directory.
Manipulating a single GPIO via /sys/class/gpio
Using a command line or a script
GPIOs in i.MX are grouped in groups of 32 pins.
For example, GPIO1_3 belong to the first group, pin 3. Its absolute number will be 3.
GPIO4_21 will be (4-1)*32+21=117.
Assuming this GPIO is defined in your device tree, the following is an example of how to use it from userspace.
To export the GPIO for userspace use:
$ echo 117 > /sys/class/gpio/export
To configure as output:
$ echo out > /sys/class/gpio/gpio117/direction
Set GPIO high:
$ echo 1 > /sys/class/gpio/gpio117/value
Set GPIO low:
$ echo 0 > /sys/class/gpio/gpio117/value
To configure as input:
$ echo in > /sys/class/gpio/gpio117/direction
Read the current value:
$ cat /sys/class/gpio/gpio117/value
To free the GPIO after you're done using it:
$ echo 117 > /sys/class/gpio/unexport
Using a C application
All of the command line operations above can be translated to C code:
Reserve (export) the GPIO:
#define IMX_GPIO_NR(port, index) ((((port)-1)*32)+((index)&31)) int fd; char buf[MAX_BUF]; int gpio = IMX_GPIO_NR(4, 21); /* Just an example */ fd = open("/sys/class/gpio/export", O_WRONLY); sprintf(buf, "%d", gpio); write(fd, buf, strlen(buf)); close(fd);
Set the GPIO direction:
sprintf(buf, "/sys/class/gpio/gpio%d/direction", gpio); fd = open(buf, O_WRONLY); /* Set out direction */ write(fd, "out", 3); /* Set in direction */ write(fd, "in", 2); close(fd);
In case of out direction set the GPIO value:
sprintf(buf, "/sys/class/gpio/gpio%d/value", gpio); fd = open(buf, O_WRONLY); /* Set GPIO high status */ write(fd, "1", 1); /* Set GPIO low status */ write(fd, "0", 1); close(fd);
In case of in direction get the current GPIO value:
char value; sprintf(buf, "/sys/class/gpio/gpio%d/value", gpio); fd = open(buf, O_RDONLY); read(fd, &value, 1); if (value == '0') { /* Current GPIO status low */ } else { /* Current GPIO status high */ } close(fd);
Once finished, free (unexport) the GPIO:
fd = open("/sys/class/gpio/unexport", O_WRONLY); sprintf(buf, "%d", gpio); write(fd, buf, strlen(buf)); close(fd);
Important notes:
- Remember that after the first read operation the file pointer will move to the next position in the file, so to get a correct value for each read operation you simply have to set the file pointer at the beginning of the file before read by using the following command:
lseek(fd, 0, SEEK_SET);
- This is only a short example. If you want to use it in your code remember add error handling to it.
Kernel Device Tree GPIO configuration
Device Tree GPIO files
Pin Func files
In the directory arch/arm64/boot/dts/freescale of the Linux kernel source you will find the pin functions definition files.
The relevant file is imx8mq-pinfunc.h.
If you search it for GPIO4_IO2, for example, you will see a group of definitions with same prefix (pad name), "MX8MQ_IOMUXC_SAI1_RXD0".
#define MX8MQ_IOMUXC_SAI1_RXD0_SAI1_RX_DATA0 0x164 0x3CC 0x000 0x0 0x0 #define MX8MQ_IOMUXC_SAI1_RXD0_SAI5_RX_DATA0 0x164 0x3CC 0x4D4 0x1 0x1 #define MX8MQ_IOMUXC_SAI1_RXD0_CORESIGHT_TRACE0 0x164 0x3CC 0x000 0x4 0x0 #define MX8MQ_IOMUXC_SAI1_RXD0_GPIO4_IO2 0x164 0x3CC 0x000 0x5 0x0 #define MX8MQ_IOMUXC_SAI1_RXD0_CCMSRCGPCMIX_BOOT_CFG0 0x164 0x3CC 0x000 0x6 0x0 #define MX8MQ_IOMUXC_SAI1_RXD0_SIM_M_HADDR17 0x164 0x3CC 0x000 0x7 0x0
Adding only the one with the GPIO4_IO2 suffix (function) to your dts file will let you use the pin as GPIO.
Define a pin as GPIO in the kernel Device Tree
You need to add the relevant definitions to your device tree, as explained in the Pin Func files section above.
Edit arch/arm64/boot/dts/freescale/fsl-imx8mq-var-dart-common.dtsi and add the definition for the GPIO you need in the iomuxc node.
&iomuxc { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_hog>; imx8m-var-dart { pinctrl_hog: hoggrp { fsl,pins = < /* Add your GPIO definitions here */ >; }; }; … };
Device Tree GPIO attribute
If you look at the pin control definitions in arch/arm64/boot/dts/freescale/fsl-imx8mq-var-dart-common.dtsi in the Linux kernel source tree, the number to the right of the pin mux macro can be used for additional attributes like pull-up, slew rate, open drain, drive strength, etc.
This value is written to the IOMUXC_SW_PAD_CTRL_ register of the relevant pin.
Please consult the SOC reference manual for details about the relevant register.