gpiolib: allow to specify the firmware node in struct gpio_chip

Software nodes allow us to represent hierarchies for device components
that don't have their struct device representation yet - for instance:
banks of GPIOs under a common GPIO expander. The core gpiolib core
however doesn't offer any way of passing this information from the
drivers.

This extends struct gpio_chip with a pointer to fwnode that can be set
by the driver and used to pass device properties for child nodes.

This is similar to how we handle device-tree sub-nodes with
CONFIG_OF_GPIO enabled.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 467f4a8..4d66676 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -593,7 +593,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
                               struct lock_class_key *lock_key,
                               struct lock_class_key *request_key)
 {
-       struct fwnode_handle *fwnode = gc->parent ? dev_fwnode(gc->parent) : NULL;
+       struct fwnode_handle *fwnode = NULL;
        struct gpio_device *gdev;
        unsigned long flags;
        int base = gc->base;
@@ -601,6 +601,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
        int ret = 0;
        u32 ngpios;
 
+       if (gc->fwnode)
+               fwnode = gc->fwnode;
+       else if (gc->parent)
+               fwnode = dev_fwnode(gc->parent);
+
        /*
         * First: allocate and populate the internal stat container, and
         * set up the struct device.

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index a673a35..b0728c8 100644 (file)
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -289,6 +289,7 @@ struct gpio_irq_chip {
  *     number or the name of the SoC IP-block implementing it.
  * @gpiodev: the internal state holder, opaque struct
  * @parent: optional parent device providing the GPIOs
+ * @fwnode: optional fwnode providing this controller's properties
  * @owner: helps prevent removal of modules exporting active GPIOs
  * @request: optional hook for chip-specific activation, such as
  *     enabling module power and clock; may sleep
@@ -377,6 +378,7 @@ struct gpio_chip {
        const char              *label;
        struct gpio_device      *gpiodev;
        struct device           *parent;
+       struct fwnode_handle    *fwnode;
        struct module           *owner;
 
        int                     (*request)(struct gpio_chip *gc,