topic Re: gpio-hog and gpio export in i.MX Processors

gpio-hog and gpio export

delauratfrançoi — Wed, 27 Jul 2016 14:55:02 GMT

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.

Re: gpio-hog and gpio export

igorpadykov — Thu, 28 Jul 2016 01:42:21 GMT

Hi François

for creating GPIO entries one can look at

i.MX51 Device Tree GPIO as output

Best regards

igor

-----------------------------------------------------------------------------------------------------------------------

Note: If this post answers your question, please click the Correct Answer button. Thank you!

-----------------------------------------------------------------------------------------------------------------------

Re: gpio-hog and gpio export

delauratfrançoi — Fri, 29 Jul 2016 06:02:56 GMT

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.

Re: gpio-hog and gpio export

delauratfrançoi — Fri, 29 Jul 2016 06:07:26 GMT

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.

Re: gpio-hog and gpio export

igorpadykov — Fri, 29 Jul 2016 06:19:51 GMT

Hi Francois

as this is general linux question suggest to post this on

linux device tree resources like

Device Tree - eLinux.org

Best regards

igor

Re: gpio-hog and gpio export

nxp_com — Sat, 16 Feb 2019 09:38:46 GMT

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"

Re: gpio-hog and gpio export

nxp_com — Sat, 16 Feb 2019 11:29:41 GMT

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

Re: gpio-hog and gpio export

igorpadykov — Tue, 19 Feb 2019 01:18:12 GMT

Hi Damiano

nxp has extended support for porting issues

NXP Professional Services | NXP

Best regards
igor