gpio: Add Avionic Design N-bit GPIO expander support

This commit adds a driver for the Avionic Design N-bit GPIO expander.
The expander provides a variable number of GPIO pins with interrupt
support.

Changes in v2:
- allow building the driver as a module
- assign of_node unconditionally
- use linear mapping IRQ domain
- properly cleanup IRQ domain
- add OF device table and annotate device tables
- emulate rising and falling edge triggers
- increase #gpio-cells to 2
- drop support for !OF
- use IS_ENABLED to conditionalize DEBUG_FS code

Changes in v3:
- make IRQ support runtime configurable (interrupt-controller property)
- drop interrupt-controller and #interrupt-cells from DT binding
- add inline to_adnp() function to wrap container_of() macro
- consistently use adnp as name for struct adnp variables
- remove irq_mask_cur and rename irq_mask to irq_enable
- fix a subtle deadlock in adnp_gpio_direction_output()
- remove dynamic allocations from debugfs code
- rename regs to num_regs to avoid confusion
- annotate non-trivial code with comments
- don't acquire mutex in adnp_gpio_get()
- assume NO_IRQ == 0

Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: linux-kernel@vger.kernel.org
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 153caceeb053..710f2b6f6f04 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_GPIO_GENERIC)	+= gpio-generic.o
 
 obj-$(CONFIG_GPIO_74X164)       += gpio-74x164.o
 obj-$(CONFIG_GPIO_AB8500)       += gpio-ab8500.o
+obj-$(CONFIG_GPIO_ADNP)         += gpio-adnp.o
 obj-$(CONFIG_GPIO_ADP5520)      += gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)      += gpio-adp5588.o
 obj-$(CONFIG_GPIO_AMD8111)      += gpio-amd8111.o