gpio: add a data pointer to gpio_chip
This adds a void * pointer to gpio_chip so that driver can
assign and retrieve some states. This is done to get rid of
container_of() calls for gpio_chips embedded inside state
containers, so we can remove the need to have the gpio_chip
or later (planned) struct gpio_device be dynamically allocated
at registration time, so that its struct device can be properly
reference counted and not bound to its parent device (e.g.
a platform_device) but instead live on after unregistration
if it is opened by e.g. a char device or sysfs.
The data is added with the new function gpiochip_add_data()
and for compatibility we add static inline wrapper function
gpiochip_add() that will call gpiochip_add_data() with
NULL as argument. The latter will be removed once we have
exorcised gpiochip_add() from the kernel.
gpiochip_get_data() is added as a static inline accessor
for drivers to quickly get their data out.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ca66302..905408b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -301,7 +301,7 @@
}
/**
- * gpiochip_add() - register a gpio_chip
+ * gpiochip_add_data() - register a gpio_chip
* @chip: the chip to register, with chip->base initialized
* Context: potentially before irqs will work
*
@@ -309,7 +309,7 @@
* because the chip->base is invalid or already associated with a
* different chip. Otherwise it returns zero as a success code.
*
- * When gpiochip_add() is called very early during boot, so that GPIOs
+ * When gpiochip_add_data() is called very early during boot, so that GPIOs
* can be freely used, the chip->parent device must be registered before
* the gpio framework's arch_initcall(). Otherwise sysfs initialization
* for GPIOs will fail rudely.
@@ -317,7 +317,7 @@
* If chip->base is negative, this requests dynamic assignment of
* a range of valid GPIOs.
*/
-int gpiochip_add(struct gpio_chip *chip)
+int gpiochip_add_data(struct gpio_chip *chip, void *data)
{
unsigned long flags;
int status = 0;
@@ -329,6 +329,8 @@
if (!descs)
return -ENOMEM;
+ chip->data = data;
+
if (chip->ngpio == 0) {
chip_err(chip, "tried to insert a GPIO chip with zero lines\n");
return -EINVAL;
@@ -415,7 +417,7 @@
chip->label ? : "generic");
return status;
}
-EXPORT_SYMBOL_GPL(gpiochip_add);
+EXPORT_SYMBOL_GPL(gpiochip_add_data);
/**
* gpiochip_remove() - unregister a gpio_chip