Add gpio base address reading in the driver; in old code, it just
returns -1 to gpio->chip.base.
Fixes: 7ee2d5b4d4340353 ("ARM: dts: nuvoton: Add Fii Kudo system")
Signed-off-by: Hongwei Zhang <[email protected]>
---
drivers/gpio/gpio-aspeed.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c
index d07bf2c3f136..4ebe4c40154c 100644
--- a/drivers/gpio/gpio-aspeed.c
+++ b/drivers/gpio/gpio-aspeed.c
@@ -1140,7 +1140,7 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
const struct of_device_id *gpio_id;
struct aspeed_gpio *gpio;
int rc, i, banks, err;
- u32 ngpio;
+ u32 ngpio, base;
gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
@@ -1179,7 +1179,10 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
gpio->chip.set = aspeed_gpio_set;
gpio->chip.set_config = aspeed_gpio_set_config;
gpio->chip.label = dev_name(&pdev->dev);
- gpio->chip.base = -1;
+ err = of_property_read_u32(pdev->dev.of_node, "base", &base);
+ gpio->chip.base = (u16) base;
+ if (err)
+ gpio->chip.base = -1;
/* Allocate a cache of the output registers */
banks = DIV_ROUND_UP(gpio->chip.ngpio, 32);
--
2.17.1
Hello,
On Thu, 14 Jan 2021, at 09:08, Hongwei Zhang wrote:
> Add gpio base address reading in the driver; in old code, it just
> returns -1 to gpio->chip.base.
Why do you want to do this? It feels hacky. The base address only affects the
legacy sysfs number-space, and even then if you're using the sysfs interface
you can discover the base address for a specific gpiochip via the associated
attribute. For example:
# cat /sys/bus/platform/devices/1e780000.gpio/gpio/gpiochip*/base
816
I feel that you should instead be changing your userspace not to assume a fixed
value.
Finally, the base value is a linux-specific thing and doesn't belong in the
devicetree, and if it did, you would also need to update the devicetree binding
in Documentation/.
Cheers,
Andrew
On Wed, Jan 13, 2021 at 11:38 PM Hongwei Zhang <[email protected]> wrote:
> Add gpio base address reading in the driver; in old code, it just
> returns -1 to gpio->chip.base.
>
> Fixes: 7ee2d5b4d4340353 ("ARM: dts: nuvoton: Add Fii Kudo system")
> Signed-off-by: Hongwei Zhang <[email protected]>
NAK, sorry.
We never allow the device tree to specify this.
First, it is a Linux-only base so it would have to be a
"linux,..." property.
Even if it is a Linux-only property, it is a bad idea.
Only people using sysfs should have any need to specify global
GPIO numbers. Don't use sysfs. Use the GPIO character device
instead. See further:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpio/TODO
Yours,
Linus Walleij