topic iMX6SX: GPIO_Init() resets IMR of all pins (gpio_imx driver @FreeRTOS) in i.MX Processors

iMX6SX: GPIO_Init() resets IMR of all pins (gpio_imx driver @FreeRTOS)

kubiznak_petr — Mon, 25 Jun 2018 07:57:00 GMT

I hit on an issue with the gpio_imx driver shipped with the FreeRTOS BSP v1.0.1 (FreeRTOS_BSP_1.0.1_iMX6SX\platform\drivers\src\gpio_imx.c). In the beggining of the GPIO_Init() function, GPIO_IMR and GPIO_EDGE_SEL registers are cleared:

    /* Register reset to default value */
    GPIO_IMR_REG(base) = 0;
    GPIO_EDGE_SEL_REG(base) = 0;

Anyway, the function serves for initialization of a single GPIO pin. When called to reinitialize a pin configuration at runtime, the settings of IMR and EDGE_SEL registers are lost for all pins on that port. I believe this is a bug and the aforementioned code should be masked to only affect a single bit, as follows:

    /* Register reset to default value */
    GPIO_IMR_REG(base) &= ~(1U << pin);
    GPIO_EDGE_SEL_REG(base) &= ~(1U << pin);

Can someone please confirm this is a correct fix? Or would that cause any side effects?

Re: iMX6SX: GPIO_Init() resets IMR of all pins (gpio_imx driver @FreeRTOS)

igorpadykov — Mon, 25 Jun 2018 23:37:20 GMT

Hi Petr

fix seems as quite sensible, I do not think it would cause any side effects.

Best regards
igor
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Re: iMX6SX: GPIO_Init() resets IMR of all pins (gpio_imx driver @FreeRTOS)

kubiznak_petr — Tue, 26 Jun 2018 06:13:35 GMT

Great, thank you Igor.