Commit 4f2f95e9 authored Apr 01, 2019 by Jan Kotas Committed by Linus Walleij Apr 05, 2019

gpio: mmio: Fix bgpio_get_set & bgpio_get_set_multiple



During my regression testing I noticed the cadence GPIO driver
fails on the latest gpio for-next tree.

I think the reason is this patch:
commit 96cd559817f2 ("Merge branch 'devel' into for-next")

Here is a part of the test log:

Loopback 8 -> 24
TESTING: gpio: 488: output direction PASSED
TESTING: gpio: 504: input direction PASSED
TESTING: gpio: 488: 0 PASSED
TESTING: gpio: 488 -> 504: 0 PASSED
TESTING: gpio: 488: 1 FAILED
TESTING: gpio: 488 -> 504: 1 FAILED
TESTING: gpio: 488: 0 PASSED
TESTING: gpio: 488 -> 504: 0 PASSED

It looks like the issue is that gc->bgpio_dir has changed its meaning.
It used to be set to the register value (so it was being inverted).

Now it's always set to 1 for output and 0 for input.
However the bgpio_get_set functions were not updated.
So they invert the bit again, which means a wrong register
is being accessed.

This patch fixes that by removing the unnecessary inversion.

Signed-off-by: Jan Kotas <jank@cadence.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

parent 542f3615

drivers/gpio/gpio-mmio.c

+2 −19

Original line number	Diff line number	Diff line
		@@ -134,17 +134,6 @@ static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
		unsigned long pinmask = bgpio_line2mask(gc, gpio);
		bool dir = !!(gc->bgpio_dir & pinmask);

		/*
		* If the direction is OUT we read the value from the SET
		* register, and if the direction is IN we read the value
		* from the DAT register.
		*
		* If the direction bits are inverted, naturally this gets
		* inverted too.
		*/
		if (gc->bgpio_dir_inverted)
		dir = !dir;

		if (dir)
		return !!(gc->read_reg(gc->reg_set) & pinmask);
		else
		@@ -164,14 +153,8 @@ static int bgpio_get_set_multiple(struct gpio_chip gc, unsigned long mask,
		/* Make sure we first clear any bits that are zero when we read the register */
		bits &= ~mask;

		/* Exploit the fact that we know which directions are set */
		if (gc->bgpio_dir_inverted) {
		set_mask = *mask & ~gc->bgpio_dir;
		get_mask = *mask & gc->bgpio_dir;
		} else {
		set_mask = *mask & gc->bgpio_dir;
		get_mask = *mask & ~gc->bgpio_dir;
		}

		if (set_mask)
		*bits \|= gc->read_reg(gc->reg_set) & set_mask;

Admin message