gpiolib: link all gpio_chips using a list
Add a list member to gpio_chip that allows all chips to be parsed
quickly. The current method requires parsing the entire GPIO integer
space, which is painfully slow. Using a list makes many chip operations
that involve lookup or parsing faster, and also simplifies the code. It
is also necessary to eventually get rid of the global gpio_desc[] array.
The list of gpio_chips is always ordered by base GPIO number to ensure
chips traversal is done in the right order.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 2034e69..b562f95 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -53,6 +53,7 @@
* @label: for diagnostics
* @dev: optional device providing the GPIOs
* @owner: helps prevent removal of modules exporting active GPIOs
+ * @list: links gpio_chips together for traversal
* @request: optional hook for chip-specific activation, such as
* enabling module power and clock; may sleep
* @free: optional hook for chip-specific deactivation, such as
@@ -98,6 +99,7 @@
const char *label;
struct device *dev;
struct module *owner;
+ struct list_head list;
int (*request)(struct gpio_chip *chip,
unsigned offset);