i.MX31: add a simple gpio driver

This is a minimal driver, so far only managing output. It will
be used by the mxc_spi.c driver.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

drivers/gpio/Makefile

@@ -25,7 +25,8 @@ include $(TOPDIR)/config.mk
 
 LIB 	:= $(obj)libgpio.a
 
-COBJS-$(CONFIG_PCA953X)	+= pca953x.o
+COBJS-$(CONFIG_MX31_GPIO)	+= mx31_gpio.o
+COBJS-$(CONFIG_PCA953X)		+= pca953x.o
 
 COBJS	:= $(COBJS-y)
 SRCS 	:= $(COBJS:.o=.c)

drivers/gpio/mx31_gpio.c

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2009
+ * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <common.h>
+#include <asm/arch/mx31.h>
+#include <asm/arch/mx31-regs.h>
+
+/* GPIO port description */
+static unsigned long gpio_ports[] = {
+	[0] = GPIO1_BASE,
+	[1] = GPIO2_BASE,
+	[2] = GPIO3_BASE,
+};
+
+int mx31_gpio_direction(unsigned int gpio, enum mx31_gpio_direction direction)
+{
+	unsigned int port = gpio >> 5;
+	u32 l;
+
+	if (port >= ARRAY_SIZE(gpio_ports))
+		return 1;
+
+	gpio &= 0x1f;
+
+	l = __REG(gpio_ports[port] + GPIO_GDIR);
+	switch (direction) {
+	case MX31_GPIO_DIRECTION_OUT:
+		l |= 1 << gpio;
+		break;
+	case MX31_GPIO_DIRECTION_IN:
+		l &= ~(1 << gpio);
+	}
+	__REG(gpio_ports[port] + GPIO_GDIR) = l;
+
+	return 0;
+}
+
+void mx31_gpio_set(unsigned int gpio, unsigned int value)
+{
+	unsigned int port = gpio >> 5;
+	u32 l;
+
+	if (port >= ARRAY_SIZE(gpio_ports))
+		return;
+
+	gpio &= 0x1f;
+
+	l = __REG(gpio_ports[port] + GPIO_DR);
+	if (value)
+		l |= 1 << gpio;
+	else
+		l &= ~(1 << gpio);
+	__REG(gpio_ports[port] + GPIO_DR) = l;
+}

include/asm-arm/arch-mx31/mx31.h

@@ -27,4 +27,24 @@
 extern u32 mx31_get_ipg_clk(void);
 extern void mx31_gpio_mux(unsigned long mode);
 
+enum mx31_gpio_direction {
+	MX31_GPIO_DIRECTION_IN,
+	MX31_GPIO_DIRECTION_OUT,
+};
+
+#ifdef CONFIG_MX31_GPIO
+extern int mx31_gpio_direction(unsigned int gpio,
+			       enum mx31_gpio_direction direction);
+extern void mx31_gpio_set(unsigned int gpio, unsigned int value);
+#else
+static inline int mx31_gpio_direction(unsigned int gpio,
+				      enum mx31_gpio_direction direction)
+{
+	return 1;
+}
+static inline void mx31_gpio_set(unsigned int gpio, unsigned int value)
+{
+}
+#endif
+
 #endif /* __ASM_ARCH_MX31_H */