linux-kernel - [PATCH v1] gpio: mmio: handle "ngpios" properly in bgpio

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Date:   Fri, 24 Feb 2023 12:40:07 -0500
From:   Asmaa Mnebhi <asmaa@...dia.com>
To:     <andy.shevchenko@...il.com>, <linus.walleij@...aro.org>,
        <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     Asmaa Mnebhi <asmaa@...dia.com>
Subject: [PATCH v1] gpio: mmio: handle "ngpios" properly in bgpio_init

bgpio_init uses "sz" argument to populate ngpio, which is not accurate.
Instead, read the "ngpios" property from the DT and if it
doesn't exist, use the "sz" argument. With this change, drivers no
longer need to overwrite the ngpio variable after calling bgpio_init.

Signed-off-by: Asmaa Mnebhi <asmaa@...dia.com>
---
 drivers/gpio/gpio-mmio.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index d9dff3dc92ae..f317a371c529 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -601,6 +601,7 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
 	       void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
 	       unsigned long flags)
 {
+	u32 ngpios = 0;
 	int ret;
 
 	if (!is_power_of_2(sz))
@@ -614,10 +615,15 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
 	gc->parent = dev;
 	gc->label = dev_name(dev);
 	gc->base = -1;
-	gc->ngpio = gc->bgpio_bits;
 	gc->request = bgpio_request;
 	gc->be_bits = !!(flags & BGPIOF_BIG_ENDIAN);
 
+	ret = device_property_read_u32(dev, "ngpios", &ngpios);
+	if (!ret)
+		gc->ngpio = ngpios;
+	else
+		gc->ngpio = gc->bgpio_bits;
+
 	ret = bgpio_setup_io(gc, dat, set, clr, flags);
 	if (ret)
 		return ret;
-- 
2.30.1