Hello
My name is françois I work with imx7d. I want to use a gpio in output. The gpio output is software controlled and is not connected to a button or LED. I know how creat an gpio in user space with export but I want initialize the gpio in device tree with gpio-hog.
If I don't initialize the gpio with gpio-hog in devicetree I can export the gpio but if I initialize the gpio with gpio-hog in devicetre i can not export the gpio.
is it normal?
My gpio-hog in my device tree
gpio1: gpio@30200000 {
compatible = "fsl,imx7d-gpio", "fsl,imx35-gpio";
reg = <0x30200000 0x10000>;
interrupts = <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>, /* GPIO1_INT15_0 */
<GIC_SPI 65 IRQ_TYPE_LEVEL_HIGH>; /* GPIO1_INT31_16 */
gpio-controller;
#gpio-cells = <2>;
interrupt-controller;
#interrupt-cells = <2>;
gpio102{
gpio-hog;
gpios = <2 GPIO_ACTIVE_LOW>;
output-high;
line-name = "ResetBluetooth";
};
};
Thanks,
François.
Hi François
for creating GPIO entries one can look at
i.MX51 Device Tree GPIO as output
Best regards
igor
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Hi igorpadykov
I read the document i.MX51 Device Tree GPIO as output . But I would know why if I use gpio-hog to one gpio in my devicetree , I can not use this gpio in the user space (export , unexport with this gpio)
thanks,
Best regards,
Francois.
Hi Francois
as this is general linux question suggest to post this on
linux device tree resources like
Best regards
igor
Managed to get it working, it started behaving as expected once I had a default pulldown on the pin
In the pinctrl hog I had to have
MX6QDL_PAD_GPIO_2__GPIO1_IO02 0x130b1 // GPIO2 LED Red, default pulldopwn
a ping config with a default 100k pullup 0x1b0b1 was NOT working
the definition is
&gpio1 {
led-red-gpio {
gpio-hog;
gpios = <2 0>;
output-high;
};
};
this will result in the following line in cat /sys/kernel/debug/gpio
gpio-2 ( |led-red-gpio ) out hi
Igor, take note
It is not a general question, how pincontrol works on IMX is specific to imx
I am also looking on how to use gpio-hog; with imx6q-gpio and "fsl,imx6q-iomuxc-gpr", "syscon";
So far no luck
if there is no support for imx6q in the forum you have to say it, not pretend that it is a "general question"
Hi Damiano
nxp has extended support for porting issues
NXP Professional Services | NXP
Best regards
igor
Hi Igorpadykov
I read the document i.MX51 Device Tree GPIO as output but I would know why if I use gpio-hog to one gpio I can use this gpio with export in user space.
thanks,
Best regards
François.