i.MX Processors中的主题 Re: Unimplemented set_config Function: GPIO Pin Configuration Loss on i.MX8MP

Unimplemented set_config Function: GPIO Pin Configuration Loss on i.MX8MP

alexandreMarquis — Mon, 06 May 2024 21:21:13 GMT

Hi everyone,

I'm currently working with the i.MX8MP platform and encountered an issue while configuring a GPIO pin in input/pull-up mode. Here's the scenario:

In one of my drivers, the pin is used in output mode during the probe phase and then switched back to input mode. However, after this process, I found that the pin loses its configuration and is no longer in pull-up mode.

here is the dtb:

gt928@5d {
[...]
pincrtl-0 = <&pinctrl_ts>;
gt928,irq-gpios = <&gpio1 6 GPIO_PULL_UP>;
};

pinctrl_ts: tsgrp {
fsl,pins = <
MX8MP_IOMUXC_GPIO1_IO06__GPIO1_IO06 0x146 /* 0x146 == pull up, drive strength = 6 */
MX8MP_IOMUXC_SD1_DATA4__GPIO2_IO06 0xd6
>;
};

Here's the call stack for reference:

[ 14.630895] gpio_do_set_config+0x24/0x74
[ 14.630905] gpio_set_config_with_argument+0x38/0x44
[ 14.630911] gpio_set_bias+0x84/0xa4
[ 14.643448] gpiod_direction_input+0x198/0x1ac
[ 14.647892] goodix_irq_direction_input+0x40/0xa4 [goodix]
[ 14.653388] goodix_ts_probe+0x3fc/0x5c8 [goodix]

Upon further investigation, I noticed that the set_config function is not implemented (gpiolib.c do the following check):

gpio_do_set_config(struct gpio_chip *gc, unsigned int offset, unsigned long config) {
{
 if (!gc->set_config)
    return -ENOTSUPP;
[...]
}

I'm curious as to why set_config hasn't been implemented.

I've seen that other have done it :

gc->set_config = pca953x_gpio_set_config; or gc->set_config = ep93xx_gpio_set_config;

Any insights or suggestions on how to address this issue would be greatly appreciated.

Thank you in advance for your help!

Best regards,
Alexandre

Re: Unimplemented set_config Function: GPIO Pin Configuration Loss on i.MX8MP

Zhiming_Liu — Tue, 07 May 2024 00:50:17 GMT

Hi @alexandreMarquis

The gpio iomux value has been written with imx_pmx_set before gpio driver probe, so there is no need to use set_config function in gpio driver. The imx_pinctrl_probe

For gpio io expander driver, this function is need, because there is no another driver setting pull up/down.

Best Regards

Zhiming

Re: Unimplemented set_config Function: GPIO Pin Configuration Loss on i.MX8MP

alexandreMarquis — Tue, 07 May 2024 11:59:16 GMT

I see, but then my question would be, why do i lose the pin configuration from the device-tree when I change my pin direction?

Scenario:

My pin is configure with a pull-up.
My driver load, set the pin in output. There is no more pull-up.
Put it back in input

expectation : the pin is set input, pull-up
current behaviour: the pin is set in input but the is no more pull-up on it.

From what i can see, when we call
gpiod_direction_input()

the function set the pin in input and then call the function
gpio_set_bias(struct gpio_desc *desc)

Which seem to try to restore the pull/pull down state of the pin, but as mention earlier, the no function seem to be implemented to reapply the device tree flag.

Re: Unimplemented set_config Function: GPIO Pin Configuration Loss on i.MX8MP

Zhiming_Liu — Wed, 08 May 2024 05:45:26 GMT

Hi @alexandreMarquis

I test such behavior on GPIO3_IO16(gpio-80). The iomux value in device tree will not be covered. There is no such issue using sysfs to control gpio.

NXP i.MX Release Distro 6.6-nanbield imx8mp-lpddr4-evk ttymxc1 imx8mp-lpddr4-evk login: [ 14.532349] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off imx8mp-lpddr4-evk login: root root@imx8mp-lpddr4-evk:~# echo 80 > /sys/class/gpio/export root@imx8mp-lpddr4-evk:~# cat /sys/kernel/debug/gpio gpiochip0: GPIOs 0-31, parent: platform/30200000.gpio, 30200000.gpio: gpio-10 ( |reset ) out hi ACTIVE LOW gpio-14 ( |regulator-vbus ) out hi gpiochip1: GPIOs 32-63, parent: platform/30210000.gpio, 30210000.gpio: gpio-38 ( |regulator-pcie ) out hi gpio-39 ( |PCIe reset ) out hi gpio-44 ( |cd ) in hi ACTIVE LOW gpio-51 ( |regulator-usdhc2 ) out lo gpiochip2: GPIOs 64-95, parent: platform/30220000.gpio, 30220000.gpio: gpio-80 ( |sysfs ) out hi gpiochip3: GPIOs 96-127, parent: platform/30230000.gpio, 30230000.gpio: gpio-98 ( |PHY reset ) out hi ACTIVE LOW gpio-116 ( |switch ) out hi ACTIVE LOW gpio-118 ( |PHY reset ) out hi ACTIVE LOW gpio-123 ( |regulator-can2-stby ) out lo gpio-124 ( |Headphone detection ) in lo gpio-125 ( |regulator-audio-pwr ) out hi gpiochip4: GPIOs 128-159, parent: platform/30240000.gpio, 30240000.gpio: gpio-133 ( |regulator-can1-stby ) out lo gpio-141 ( |spi1 CS0 ) out hi ACTIVE LOW gpio-149 ( |host-wake ) in hi ACTIVE LOW gpiochip5: GPIOs 512-527, parent: i2c/2-0020, 2-0020, can sleep: gpio-512 (EXT_PWREN1 ) gpio-513 (EXT_PWREN2 ) gpio-514 (CAN1/I2C5_SEL ) gpio-515 (PDM/CAN2_SEL ) gpio-516 (FAN_EN ) gpio-517 (PWR_MEAS_IO1 ) gpio-518 (PWR_MEAS_IO2 ) gpio-519 (EXP_P0_7 ) gpio-520 (EXP_P1_0 ) gpio-521 (EXP_P1_1 ) gpio-522 (EXP_P1_2 ) gpio-523 (EXP_P1_3 ) gpio-524 (EXP_P1_4 ) gpio-525 (EXP_P1_5 ) gpio-526 (EXP_P1_6 ) gpio-527 (EXP_P1_7 ) root@imx8mp-lpddr4-evk:~# memtool -32 30330380 1 E Reading 0x1 count starting at address 0x30330380 0x30330380: 00000140 root@imx8mp-lpddr4-evk:~# echo in > /sys/class/gpio/gpio80/direction root@imx8mp-lpddr4-evk:~# memtool -32 30330380 1 E Reading 0x1 count starting at address 0x30330380 0x30330380: 00000140 root@imx8mp-lpddr4-evk:~# cat /sys/kernel/debug/gpio gpiochip0: GPIOs 0-31, parent: platform/30200000.gpio, 30200000.gpio: gpio-10 ( |reset ) out hi ACTIVE LOW gpio-14 ( |regulator-vbus ) out hi gpiochip1: GPIOs 32-63, parent: platform/30210000.gpio, 30210000.gpio: gpio-38 ( |regulator-pcie ) out hi gpio-39 ( |PCIe reset ) out hi gpio-44 ( |cd ) in hi ACTIVE LOW gpio-51 ( |regulator-usdhc2 ) out lo gpiochip2: GPIOs 64-95, parent: platform/30220000.gpio, 30220000.gpio: gpio-80 ( |sysfs ) in hi gpiochip3: GPIOs 96-127, parent: platform/30230000.gpio, 30230000.gpio: gpio-98 ( |PHY reset ) out hi ACTIVE LOW gpio-116 ( |switch ) out hi ACTIVE LOW gpio-118 ( |PHY reset ) out hi ACTIVE LOW gpio-123 ( |regulator-can2-stby ) out lo gpio-124 ( |Headphone detection ) in lo gpio-125 ( |regulator-audio-pwr ) out hi gpiochip4: GPIOs 128-159, parent: platform/30240000.gpio, 30240000.gpio: gpio-133 ( |regulator-can1-stby ) out lo gpio-141 ( |spi1 CS0 ) out hi ACTIVE LOW gpio-149 ( |host-wake ) in hi ACTIVE LOW gpiochip5: GPIOs 512-527, parent: i2c/2-0020, 2-0020, can sleep: gpio-512 (EXT_PWREN1 ) gpio-513 (EXT_PWREN2 ) gpio-514 (CAN1/I2C5_SEL ) gpio-515 (PDM/CAN2_SEL ) gpio-516 (FAN_EN ) gpio-517 (PWR_MEAS_IO1 ) gpio-518 (PWR_MEAS_IO2 ) gpio-519 (EXP_P0_7 ) gpio-520 (EXP_P1_0 ) gpio-521 (EXP_P1_1 ) gpio-522 (EXP_P1_2 ) gpio-523 (EXP_P1_3 ) gpio-524 (EXP_P1_4 ) gpio-525 (EXP_P1_5 ) gpio-526 (EXP_P1_6 ) gpio-527 (EXP_P1_7 )

I think maybe you miss some code in your driver, you can refer the sysfs code, have you add mutex during your operation?

Re: Unimplemented set_config Function: GPIO Pin Configuration Loss on i.MX8MP

alexandreMarquis — Fri, 17 May 2024 19:09:59 GMT

This is how I resolved my problem.
Based on my findings, placing <&pinctrl_ts> under the touchscreen node doesn't apply the pin function correctly.

&i2c3 { clock-frequency = <400000>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_i2c3>,<&pinctrl_ts>; status = "okay"; ov5640_0: ov5640_mipi@3c { status = "disabled"; }; gt928@5d { compatible = "goodix,gt928"; reg = <0x5d>; pincrtl-names = "default"; pincrtl-0 = <&pinctrl_ts>; interrupt-parent = <&gpio1>; interrupts = <6 IRQ_TYPE_LEVEL_LOW>; gt928,irq-gpios = <&gpio1 6 GPIO_ACTIVE_HIGH>; gt928,reset-gpios = <&gpio2 6 GPIO_ACTIVE_HIGH>; touchscreen-inverted-x; status = "okay"; }; }; [...] &iomuxc { pinctrl_ts: tsgrp { fsl,pins = < MX8MP_IOMUXC_GPIO1_IO06__GPIO1_IO06 0x146 /* 0x146 == pull up, drive strength = 6 */ MX8MP_IOMUXC_SD1_DATA4__GPIO2_IO06 0xd6 >; }; };

However, when I move it to the &i2c3 node, the pins are configured properly.

Thank you for your time!