[PATCH 1/4] gpio: gpio-mxc: add gpio driver for Freescale MXC architecture

Add gpio-mxc driver by copying arch/arm/plat-mxc/gpio.c into
drivers/gpio with the following changes.

 * Use readl/writel to replace mach-specific accessors
   __raw_readl/__raw_writel

 * Migrate to platform driver by adding .probe function

 * Add a list to save all mx2 ports references, so that
   mx2_gpio_irq_handler can walk through all interrupt status
   registers

Signed-off-by: Shawn Guo <redacted>
---
 arch/arm/plat-mxc/include/mach/gpio.h |    2 +
 drivers/gpio/Makefile                 |    1 +
 drivers/gpio/gpio-mxc.c               |  423 +++++++++++++++++++++++++++++++++
 3 files changed, 426 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-mxc.c

diff --git a/arch/arm/plat-mxc/include/mach/gpio.h b/arch/arm/plat-mxc/include/mach/gpio.h
index a2747f1..87bd4ef 100644
--- a/arch/arm/plat-mxc/include/mach/gpio.h
+++ b/arch/arm/plat-mxc/include/mach/gpio.h

@@ -37,7 +37,9 @@
 #define irq_to_gpio(irq)	((irq) - MXC_GPIO_IRQ_START)
 
 struct mxc_gpio_port {
+	struct list_head node;
 	void __iomem *base;
+	int id;