please help, i need the GPIO pin to connect to my relay module using Hilink HLK-7688a board
what's left on my board is only SPI, can SPI be disabled and used as a GPIO pin that can respond to active Low or High?
I've tried changing the dts and dtsi files but the kernel panics always occur
I don’t see any Hilink devices in the table of hardware, is this an openwrt supported device?
According to the dts, the flash chip is connected via SPI, so you can't disable SPI. What about UART1 and i2c?
Thank you for the information
for UART1 I use connect to RS485 module and I2C connect to RTC module
What about i2s?
If you are really out of pins, you could add an i2c or SPI GPIO extender. If you define it in the .dts you can use the pins like any other GPIO pin.
for i2s, the GPIO has been successfully changed via the dts file, still lacking 3 gpio to connect to the relay module
Hilink HLK-7688a module, there are many GPIO you could use, how about LED0 - LED4?
The worst case is using an I2C-to-GPIO chip on I2C bus.
for LED0 - LED4 already allocated to Leds WAN1, LAN1, LAN2, Alarm1 and Alarm2
WAN1, LAN1, LAN2 indications, are not important as the Relays.
I would go for an i2c port extender then - they are easy to use, cheap and work well (e.g. PCF8574A, MCP23018, SX1509 ...). Just keep in mind that the PCF cannot source much current, it won't work with active-high relays without additional circuitry (I had to redesign a PCB because of this and me not doing enough research).
btw, it would make matters a bit easier if you told us what you have already connected and which GPIOs are already occupied.
the following GPIOs have been connected :
UART1 for RS485 . module
i2c for RTC module
i2s > 3 pins for Digital Input and 1 pin for relay module
still need 3 more GPIO pins for relay module
Surya,
I've been trying to convert I2S pins to GPIO for a couple of buttons and leds in .dts file. But no matter what I do, the voltage at the gpio rmains a 0.5v constantly, so led won't turn on.
Can you share how you did it?
After lots of trials and errors. This is what I found out for this module.
I was able to free up all I2S. Got 4 GPIOs that can be manipulated as input/output from user land.
Tried EPHY_LED0-4: Use a couple of them for ETH lights, which are controlled by the kernel, work fine. But can't use them for input or output from user land as they're always high. Tried to free group ephy but got kernel panic.
I only need 1 NIC, so tried the other 3 MDI_* pins. Not working.
I need both UART & I2C, so they're off limit.
So, it looks like the I2S and the extra GPIO0 are easily accessible. Others can possibly be hacked, but I don't want to go there yet.
Hi, I want to use GPIOs too. Could you please give me some hints to do this and also I would really appreciate it if you could provide some code examples. Many thanks
In file mt7628an_hilink_hlk-7688a.dts, I have the following block:
&state_default {
gpio {
groups = "wdt", "wled_an", "i2s", "p0led_an", "p1led_an", "p2led_an", "p3led_an", "p4led_an";
function = "gpio";
};
};
This block declares these pins as GPIOs. Where i2s means all I2S pin, p0led_an = EPHY_LED0, p1led_an = EPHY_LED1, p2led_an = EPHY_LED2, p3led_an = EPHY_LED3, p4led_an = EPHY_LED4.
Which gave me an extra 7 GPIO pins, enough for my application.
I really appreciate it. I had taken the advantage of other DTSs in ramips directory to create a dts for my device and then I used [make]. Fortunently it is like your dts so I did it right but the thing is I don't know how to use it. I tried LUCI to update my system but nothing happened! How did you install/put the dts in your device? Thank you so much
You need to modify the
target/linux/ramips/dts/mt7628an_hilink_hlk-7688a.dts
from your openwrt root directory and rebuild your openwrt.
And then, how should I install it on my device? thank you
That is not in the context of this topic. You should do research on how to build and install a custom openwrt image.