On 2014年12月01日 22:04, Linus Walleij wrote:
On Sat, Nov 29, 2014 at 8:11 AM, Zhou Wang <wangzhou.bry@xxxxxxxxx> wrote:
On 2014年11月28日 17:33, Arnd Bergmann wrote:
On Friday 28 November 2014 14:29:47 Zhou Wang wrote:
default 264 if MACH_H4700
+ default 128 if ARCH_HIP04
default 0
help
Maximum number of GPIOs in the system.
If I remember correctly, you don't actually need to set this if all gpio
clients are using the new gpio descriptor interfaces instead of gpio
numbers. Would that work for you? You'd have to know which devices
If I don't set this, it will use the default ARCH_NR_GPIO(512), then
the range of GPIO number will be 384~511 which is very strange to users,
because Hip04 based machines can only support 128 GPIOs.
That is a totally different problem.
Not that these numbers have ever been stable...
Think of a patch to gpiochip_find_base() in
drivers/gpio/gpiolib.c to fix this so that numbers are
assigned a better way rather than doing
random hacks with numbers like this.
Yours,
Linus Walleij
Hi Linus,
how about a patch like this, we read the base from the dts here.
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e8e98ca..0c40f53 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -107,11 +107,16 @@ struct gpio_chip *gpiod_to_chip(const struct
gpio_desc *desc)
EXPORT_SYMBOL_GPL(gpiod_to_chip);
/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
-static int gpiochip_find_base(int ngpio)
+static int gpiochip_find_base(struct gpio_chip *gpio_chip)
{
struct gpio_chip *chip;
+ int ngpio = gpio_chip->ngpio;
int base = ARCH_NR_GPIOS - ngpio;
+ /* just prototype */
+ if (!of_property_read_u32(gpio_chip->dev->of_node, "base", &base))
+ return base;
+
list_for_each_entry_reverse(chip, &gpio_chips, list) {
/* found a free space? */
if (chip->base + chip->ngpio <= base)
@@ -236,7 +241,7 @@ int gpiochip_add(struct gpio_chip *chip)
spin_lock_irqsave(&gpio_lock, flags);
if (base < 0) {
- base = gpiochip_find_base(chip->ngpio);
+ base = gpiochip_find_base(chip);
if (base < 0) {
status = base;
goto unlock;
Best regards,
Zhou Wang
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