Re: [PATCH 09/24] gpio: Add ZTE ZX279128S GPIO driver

From: Stefan Dösinger

Date: Sun Oct 11 2026 - 08:13:41 EST


Am Samstag, 10. Oktober 2026, 14:59:47 Mitteleuropäische Sommerzeit schrieben
Sie:
> +/*
> + * Each bank has 16 lines, one bit per line in each register. The registers
> + * at 0x04-0x10 and 0x28-0x34 control the interrupts, which are not
> supported + * yet.
> + */
> +#define ZX279128S_GPIO_DIR 0x00 /* 1: output */
> +#define ZX279128S_GPIO_DATA 0x14 /* line level */
> +#define ZX279128S_GPIO_SET 0x18 /* write 1: drive high */
> +#define ZX279128S_GPIO_CLEAR 0x1c /* write 1: drive low */

This looks identical to mine, which itself matches the old zx29 GPIO driver
with IRQ support etc that was removed in 89d4f98ae90d ("ARM: remove zte zx
platform"). This old driver had support for IRQs.

My hardware has the same register layout, but no IRQ support (related
registers are always 0). So I wasn't planning on reviving the old driver and
just using regmap-gpio like you do here. If your hardware has indeed working
GPIO IRQs it would make sense to revive the old driver.

My hardware has one annoyance: There is one GPIO line (not one block of 16,
just one single line) that has an inverted direction bit - and this line is
necessary to run the routers on battery. I don't yet know what the nicest way
to deal with this is. If we have a good reason to have our own zx gpio driver
then life would be easier :-)

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