I'm running a buildroot linux environment on a STM32MP157 dev board. I have a button with an internal pullup on pin B12. I want to fire an interrupt once the line goes low. On other linux boards like the RPi, I've been able to call gpio_to_irq(<gpio#>) and get the IRQ for that pin. Done, simple. However, on this board, there are only 16 external interrupts connected to the EXTI peripheral; they are configurable in a sense that any port may be connected to the EXTI, but the pin numbers cannot overlap. For example GPIO A12 and B12 may NOT be connected to the EXTI at the same time. I have ensured that no other devices are using and GPIO port pin 12.
I have edited my DTS file to reflect that I want my GPIO B12 connected to the EXTI controller. But so far I have had no luck in making that happen. Here is the documentation for the interrupts provided by ST. If someone can explain how to fix the device tree such that I can request the B12 interrupt from my driver I would really appreciate it.
Here's my DTS file:
/dts-v1/;
#include "stm32mp157.dtsi"
#include "stm32mp15xa.dtsi"
#include "stm32mp15-pinctrl.dtsi"
#include "stm32mp15xxac-pinctrl.dtsi"
#include "stm32mp15xx-dkx.dtsi"
/ {
model = "STMicroelectronics STM32MP157A-DK1 Discovery Board";
compatible = "st,stm32mp157a-dk1", "st,stm32mp157";
chosen {
stdout-path = "serial0:115200n8";
};
button {
compatible = "test,button";
input-gpios = <&gpiob 12 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>; //Works with pull-up once the driver is loaded.
interrupts-extended = <&gpiob 12 IRQ_TYPE_EDGE_FALLING>;
interrupt-names = "qwerty";
status = "okay";
};
led {
extern-led {
compatible = "test,led";
gpios = <&gpiob 10 GPIO_ACTIVE_HIGH>;
linux,default-trigger = "cpu";
};
};
};
I have tried the following:
interrupts-extended = <&exti 28 IRQ_TYPE_EDGE_FALLING>; (This SOC only has 16 pins per GPIO bank, so B12 is global GPIO 28)
interrupts-extended = <&gpiob 12 IRQ_TYPE_EDGE_FALLING>;
interrupt-parent = <&gpiob>;
interrupts = <12
IRQ_TYPE_EDGE_FALLING>;
Lastly, my stretch goal is to be able to request the IRQ by name, from the interrupt-name property in the device tree. Something like request_irq("qwerty"). Is that possible?
EDIT: I have temporarily connected my pushbutton to GPIO A12, and it successfully fires the interrupt, confirming that the EXTI #12 interrupt is connected to GPIO bank A. How can I go about changing this from within the device tree? Thank you in advance.
Okay I have solved this. Apparently iterating through your GPIO pins with the gpio*_to_irq() functions was the problem. When the function was called, the kernel would immediately configure the EXTI interface for that pin. I thought it was defaulting to Port A, but that was actually caused by iterating through all the GPIO pins looking for the interrupt number starting at GPIO 0, aka Port A Pin 0. So by only calling the gpio_to_irq or gpiod_to_irq function for the pins you need, the kernel will properly configure the EXTI interface for the requested pins.
Related
Context
I am using an i.MX6 ULL application processor with a Goodix 9271 touch-screen display. The display has been added to the device tree and is working correctly. I now wanted to add the touch controller, which is connected to my application processor via I²C. I therefore added
A new node under my I²C node which adds the controller as a device on the bus.
A new pin control group for the application processor to interface with the touch controller
I have enumerated them here:
/* #1: Device node on the I2C bus */
&i2c1 {
clock_frequency = <100000>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_i2c1>;
status = "okay";
/* Awesome new touch controller */
gt9271_ts#5d {
compatible = "goodix,gt9271"; /* Device tree binding */
reg = <0x5d>; /* I2C bus address */
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_gt9271_ts_gpio>; /* Custom pinctrl group node */
interrupt-parent = <&gpio4>;
interrupts = <16,0>; /* GPIO 4 + pin 16 + active high */
reset-gpios = <&gpio4 12 0>; /* GPIO 4 + Pin 12 + active high */
touchscreen-size-x = <1200>;
touchscreen-size-y = <800>;
touchscreen-inverted-x;
touchscreen-inverted-y;
};
/* ... */
};
/* #2: Pin control group */
&iomuxc {
pinctrl_gt9271_ts_gpio: gt9271_ts_gpiogrp {
fsl,pins = <
MX6UL_PAD_NAND_DQS__GPIO4_IO16 0x80000000 /* Interrupt */
MX6UL_PAD_NAND_READY_B__GPIO4_IO12 0x80000000 /* Reset */
>;
};
/* ... */
};
Explanation: bus address
The device data sheet, available here, indicates that two slave addresses are supported: 0xBA/0xBB and 0x28/0x29. The device is set to use 0xBA/0xBB adjusted for 7-bit addressing as recommended in this binding, (so the address assigned in the node is actually 0x5d).
Explanation: control pins
The I²C reset and interrupt are connected (respectively) to GPIO 4, pin 16, and GPIO 4, pin 12. These are reserved for NAND but NAND is not being used with this processor so the pins are free.
Problem
Unfortunately, the touchscreen controller configuration I have added is failing on boot with an I²C related message. I am greeted on boot with the following:
[ 2.118110] Goodix-TS 0-005d: 0-005d supply AVDD28 not found, using dummy regulator
[ 2.126059] Goodix-TS 0-005d: 0-005d supply VDDIO not found, using dummy regulator
[ 2.134510] Goodix-TS 0-005d: i2c test failed attempt 1: -6
[ 2.177733] Goodix-TS 0-005d: i2c test failed attempt 2: -6
[ 2.217377] Goodix-TS 0-005d: I2C communication failure: -6
I have attempted to search the error code (-6) but find sparse to non-existent search results online. I've checked that the connector is physically there and it seems to be.
What steps might I take to diagnose such an error code?
The solution is as follows:
The documentation states that I should include the property in the format irq-gpios. I previously thought I only needed the interrupts property. After adding irq-gpios = <&gpio4 16 0>;, the device passed the I2C test.
I disabled touchscreen-inverted-x;, and touchscreen-inverted-y; by removing those lines. I had incorrectly assumed I needed to do that originally.
Verdict:
Try to follow the documentation precisely.
My Raspberry Pi 3B runs Jessie-Lite. I would like to configure Physical pin 12/BCM pin 18/Wiring Pi pin 1 to be an output, set to low.
On Stretch, this can be done easily via config.txt
gpio=18=op,dl
On previous versions, this is apparently done by editing the dt-blob.dts file (https://www.raspberrypi.org/documentation/configuration/pin-configuration.md)
However, in the section for pins_3b1 or pins_3b2 (Pi 3 B), I cannot find a reference corresponding to my target pin (Physical pin 12/BCM pin 18/Wiring Pi pin 1). There is no pin#p12 or pin#p18. There is a pin#p1 but inside the videcore {} section.
Thank you.
[From https://www.raspberrypi.org/forums/viewtopic.php?f=107&t=237796&p=1453560#p1453560]
The dt-blob is not meant to list all pins - just those with a specific function and that require a non-default value. If you were to initialise GPIO18 from the dt-blob to be an output driving low you would need to add something like:
pin#p18 { function = "output"; startup_state = "active"; termination = "no_pulling"; polarity = "active_low"; };
I have found examples of basic arduino to arduino serial communication but have been unable to get those working on ESP32 boards. I am trying to make the same thing work between two ESP32's The two are connected:
esp1 esp2
gnd to gnd
tx2 to rx2
rx2 to tx2
Simple sketches:
//transmit sketch
void setup() {
Serial.begin(9600);
}
void loop() {
Serial.println("test...");
delay(1000);
}
//receive sketch
void setup() {
Serial.begin(9600);
}
void loop() {
String received = "";
while (Serial.available())
{
received = Serial.read();
Serial.println(received);
}
}
What else is required to make this work?
I think your code comes from a simpler world in which pins were always fixed and one UART was all you had available. With the ESP32 you should probably look for a solution more along these lines:
#include <HardwareSerial.h>
HardwareSerial Serial2(2); // use uart2
Serial2.begin(19200, SERIAL_8N1, 16, 17); // pins 16 rx2, 17 tx2, 19200 bps, 8 bits no parity 1 stop bit
I hope this helps. If you still have problems after this, they're likely to be either a) the board you're using doesn't use 16 & 17 for rx2 & tx2, or b) you need 10k pull-up (not series) resistors on both lines to stop them "floating" - however some boards take care of the pull-ups for you.
All the following criteria should be meet to make it work:
ESP32 board should not use the serial port you want to use to any embedded feature. So it should be free to use.
Make sure you are using the right pins:
U
Rx
Tx
Serial
40
41
Serial1
9
10
Serial2
16
17
Make sure lines are crossed, so Tx is bind to Rx on the other board and vice versa.
Make sure that the speed is the same on both board.
To see the result both ESP32 board should be connected to the PC via USB and a console should attached to the USB ports. You can use putty for this purpose to connect the USB ports. Two instances can be run for the two USB port. Make sure the speed setup in putty is the same as it is in the code.
Whatever you type in one console will be transferred and will appear on the other console.
Upload this code to both ESP32 board:
HardwareSerial &hSerial = Serial1; //can be Serial2 as well, just use proper pins
void setup()
{
Serial.begin(115200);//open serial via USB to PC on default port
hSerial.begin(115200);//open the other serial port
}
void loop()
{
if (Serial.available()) //check incoming on default serial (USB) from PC
{
hSerial.write(Serial.read()); // read it from UBS and send it to hSerial
}
if (hSerial.available()) //check incoming on other serial from the other board
{
Serial.write(hSerial.read()); //read it from hSerial and send it to UBS
}
}
System is basic but I have terrible problem and I can not solve it pls help me. When my system works PIC keep running but clear the registers 4-5 times in a day.
How system should work:
-I have a PIC, pneumatic cylinder and 3 sensor(works with 24V DC).
-Main sensor take the signal from another system.
-When a signal came from main sensor, if the cyclinder is backward, cylinder should go to forward until forward sensor see it and if the cylinder is forward, cyclinder should come to backward until backward sensor see it.
Program:
#include <16F628A.h>
#FUSES NOWDT //No Watch Dog Timer
#FUSES NOBROWNOUT //No brownout reset
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or
B5(PIC18) used for I/O
#use delay(crystal=4000000)
#use fast_io(a)
#use fast_io(b)
#define goForward PIN_A0
#define comeBackward PIN_A1
#define main_sensor PIN_B0
#define positionSensorForward PIN_B5
#define positionSensorBackward PIN_B4
int1 pistonPositionedForward=0, pistonPositionedBackward=1;
int1 positionForwardReg=0, positionBackwardReg=0;
int1 pistonForwarding=0, pistonBackwarding=0;
#priority rb,ext
#int_RB NOCLEAR
void B_change()
{
positionForwardReg=input(positionSensorForward);
positionBackwardReg=input(positionSensorBackward);
if(positionForwardReg&&pistonForwarding) //if forwarding and forward sensor see
{
disable_interrupts(INT_RB);
output_low(goForward);
pistonPositionedForward=1;
pistonPositionedBackward=0;
write_eeprom(0,1);
write_eeprom(1,0);
pistonForwarding=0;
pistonBackwarding=0;
clear_interrupt(int_ext);
enable_interrupts(INT_EXT);
}
else if(positionBackwardReg&&pistonBackwarding) //if backwarding and backward sensor see
{
disable_interrupts(INT_RB);
output_low(comeBackward);
pistonPositionedForward=0;
pistonPositionedBackward=1;
write_eeprom(0,0);
write_eeprom(1,1);
pistonForwarding=0;
pistonBackwarding=0;
clear_interrupt(int_ext);
enable_interrupts(INT_EXT);
}
clear_interrupt(int_rb);
}
#int_ext NOCLEAR
void ext_interrupt()
{
disable_interrupts(INT_EXT);
positionForwardReg=input(positionSensorForward);
positionBackwardReg=input(positionSensorBackward);
if(positionForwardReg^positionBackwardReg) //if one of position sensor is see then position according to sensor, else position according to memory
{
pistonPositionedForward=positionForwardReg;
pistonPositionedBackward=positionBackwardReg;
}
if(pistonPositionedForward)
{
pistonBackwarding=1;
pistonForwarding=0;
output_high(comeBackward);
clear_interrupt(int_rb);
enable_interrupts(INT_RB);
}
else if(pistonPositionedBackward)
{
pistonForwarding=1;
pistonBackwarding=0;
output_high(goForward);
clear_interrupt(int_rb);
enable_interrupts(INT_RB);
}
clear_interrupt(int_ext);
}
void main()
{
//to remember last position after power off
pistonPositionedForward=read_eeprom(0);
pistonPositionedBackward==read_eeprom(1);
set_tris_a(0x00);
set_tris_b(0xFF);
output_a(0x00);
delay_ms(1000);
ext_int_edge(L_TO_H);
clear_interrupt(int_ext);
enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);
while(TRUE)
{
}
}
And my circuit:
CIRCUIT
*j2,j3 connected selonoid valve
*J4,J5,J6 connected 3 sensors 1. pin +24VDC,2. pin GND, 3.pin sensor data
***B1 and B2 connections changed. Now B1 connected to B5,B2 connected to B4
And These are I tried:
-I have 3 PIC all of them do same thing
-I changed 24V power supply
-I cancelled 7805 and 7812 and I connected seperate 5V power supply istead of 7805.
I am debugging via LEDs. Sometimes system stop running just waiting at one of positions. Take main sensor signal but doesnot anything, And pistonPositionedForward and pistonPositionedBackward register values are 0. I cant find problem how can it clear these registers?
You have unconnected pins on RB that are configured as inputs, with no internal pull ups set. Electrical noise may well trigger unwanted interrupts on PORTB, that has been known to happen.
The use of interrupts is making the overall logic a bit hard to follow for such a simple device. Have you tried rewriting the program NOT using interrupts (except maybe for EXT)? It should not take long and I think it may greatly improve the reliability - and maintainability, without impacting performance of the physical system.
I suggest you first configure the unused PORTA and PORTB pins as outputs, and see if the problem goes away. If that fails, a rewrite not using interrupts should take no more than an hour. This would probably make sense since that is probably way shorter than the time you have already spent chasing the issue.
Reading the description, I came up with this solution.
#include <16F628A.h>
#FUSES NOWDT //No Watch Dog Timer
#FUSES NOBROWNOUT //No brownout reset
#FUSES NOLVP //No low voltage prgming, B5(PIC18) used for I/O
#use delay(crystal=4000000)
#use fast_io(a)
#use fast_io(b)
#define FWD_MOVE PIN_A0
#define BACK_MOVE PIN_A1
#define PORTA_RESET (0x00) // outputs=LO, unused pins as outputs
#define PORTA_TRISTATE (0x00)
#define EXT_SENSOR PIN_B0
#define FWD_REST PIN_B5
#define BACK_REST PIN_B4
#define PORTB_RESET (0xCE) // can't use pull ups because of HW logic...
#define PORTB_TRISTATE (0x31)
#define EEPROM_STATUS_ADDR (0x0000)
#define EEPROM_STATUS_FWD (0x01)
#define EEPROM_STATUS_BACK (0x00)
int1 extLast;
int1 extCur;
void main()
{
// setup
output_a(PORTA_RESET):
output_b(PORTB_RESET):
// setting to last known state...
// safety check.
output_low(FWD_MOVE);
output_low(BACK_MOVE);
// This will activate the outputs to make sure we have good
// positioning.
switch(eeprom_read(EEPROM_STATUS_ADDR))
{
default: // EEPROM error... I'll let you decide what to do here.
// either move forward or back.
// this implementation goes back by default.
eeprom_write(EEPROM_STATUS_ADDR, EEPROM_STATUS_BACK);
disable_interrupts(GLOBAL);
// falling through...
case EEPROM_STATUS_BACK:
output_high(BACK_MOVE);
break;
case EEPROM_STATUS_FWD:
output_high(FWD_MOVE);
break;
}
// activate outputs... watch your fingers!
set_tris_a(PORTA_TRISTATE);
set_tris_b(PORTB_TRISTATE);
extLast = input(EXT_SENSOR);
for (;;)
{
// read external sensor, take action.
extCur = input(EXT_SENSOR);
if (extCur && !extlast)
{
// safety check.
output_low(FWD_MOVE);
output_low(BACK_MOVE);
// control logic
switch(eeprom_read(EEPROM_STATUS_ADDR))
{
default: // should never happen.
// falling through...
case EEPROM_STATUS_BACK:
output_high(FWD_MOVE);
eeprom_write(EEPROM_STATUS_ADDR, EEPROM_STATUS_FWD);
disable_interrupts(GLOBAL);
break;
case EEPROM_STATUS_FWD:
output_high(BACK_MOVE);
eeprom_write(EEPROM_STATUS_ADDR, EEPROM_STATUS_BACK);
disable_interrupts(GLOBAL);
break;
}
}
extLast = extCur;
// mechanical interface:
// read the limit guards and stop movement when done.
if (input(FWD_REST))
{
output_low(FWD_MOVE);
}
if (input(BACK_REST))
{
output_low(BACK_MOVE);
}
}
}
Of course, I could not check the above code on-site :).
After reviewing the schematics, I must also advise to add 1N4001 diodes in parallel of the 2 output MOSFETS to give them better protection against reverse voltage spikes. MOSFET built-in diodes are not very sturdy. 1N4148 or 1N914 would work there as well.
The 16F628 has very limited stack space. It looks like you are experiencing stack overflow during the call to write_eeprom. Calling write_eeprom from an interrupt may not be such a good idea after all.
There was a bug in older CCS compilers, related to the use of write_eeprom. It seems write_eeprom is enabling interrupts during the call. I've added calls to disable interrupts after the writes. I don't know if that bug was fixed, since I never use CCS.
[EDIT] after checking your HW. I realized you cannot use internal pull-ups because the HW logic is positive-going. The pull-ups in the PIC are meant to work with NPN transistors in the open collector configuration (emitter to ground). I changed the code accordingly.
The way you write to EEPROM is not good. eeprom writes take time, and the second write is usually taken care of in the eeprom interrupt. The CCS bug that enables the global interrupt and unmask the EEIE in eeprom_write does not help. Unhandled interrupts do generate a reset.
I'm working on a board based on the iMX6 and am trying to configure a number of GPIOs that are being used as chip enable and reset lines. Based on the research I've done, the way to handle this is via the gpio-reset driver in the device tree. Following the documentation I've come up with the below code which compiles but I'm not sure how to then control these reset lines from user space.
The first device tree driver I used was the gpio-leds which created an leds folder in sys/class with nodes to control the LED. However I don't see anything similar for reset. So I have 2 questions:
1) Is GPIO-RESET the correct binding to use for controlling reset lines, enable lines, etc.
2) Is there documentation on how to handle this and other bindings from user space, similar to how I'm controlling the GPIO-LED?
Kernel: Linux buildroot 4.1.15
/dts-v1/;
#include <dt-bindings/input/input.h>
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/pinctrl/omap.h>
#include "imx6ul.dtsi"
/ {
model = "Freescale i.MX6 UltraLite 14x14 EVK Board";
compatible = "fsl,imx6ul-14x14-evk", "fsl,imx6ul";
memory {
reg = <0x80000000 0x20000000>;
};
/* Reset Line Configuration */
gpio_resets {
compatible = "linux,gpio-reset";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_gpioreset>;
gnss {
gpios = <&gpio1 4 0>;
asserted-state = <0>;
duration-ms = <100>;
auto;
};
};
...
};
&iomuxc {
pinctrl-names = "default";
imx6ul-evk {
pinctrl_gpioreset:
gpiorstgrp {
fsl,pins = <
MX6UL_PAD_GPIO1_IO04__GPIO1_IO04 0x000010B0 /* GNSS RESET_N */
>;
};
...
};
I'm not exactly sure about the gpio-reset sysfs interface as I couldn't find any information in bindings documentation, but for the normal gpio interface you need to export the gpio before it will show up in /sys/class/gpio/gpio*. Basically you just need to write the number of the gpio you wish to use to the export file underneath /sys/class/gpio. Here is an example of someone doing that. If you're just toggling the gpio on/off that interface should be enough.
Is GPIO-RESET the correct binding to use for controlling reset lines, enable lines, etc.
I have been looking for such a driver too.
I can see that there was a proposal for exactly this:
https://lwn.net/Articles/585145/
but I cannot find it in my kernel version (tracking the 5.4.y releases).
Only in some stale imx6 kernel: https://github.com/samnazarko/linux-imx6/blob/master/Documentation/devicetree/bindings/reset/gpio-reset.txt
So I will either
create a small driver to support the "delayed" function based on the above proposal (time of asserting the reset at boot).
use gpio-led with a default-state. Maybe using the "one-shot" trigger, to provide a single-write API to my apps. (Write once to the sysfs shot file results in a single toggle of the pin for a configurable time.)
Totally handle it from the userspace via libgpio or sysfs. (Maybe combined with gpio-led, to have at least a clearly defined state of the line during boot.)