| Message ID | 20210113223808.31626-2-hongweiz@ami.com |
|---|---|
| State | New |
| Headers | show |
| Series | gpio: aspeed: Add gpio base address reading | expand |
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 <hongweiz@ami.com> 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 <hongweiz@ami.com> 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
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);
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 <hongweiz@ami.com> --- drivers/gpio/gpio-aspeed.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)