nios2: add gpio support to nios2-generic board

This patch adds gpio support of Altera PIO component to the
nios2-generic board. Though it drives only gpio_led at the
moment, it supports bidirectional port to control bit-banging
I2C, NAND flash busy status or button switches, etc.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Tested-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>

board/altera/nios2-generic/Makefile

@@ -32,6 +32,7 @@ LIB	= $(obj)lib$(BOARD).a
 COBJS-y	:= $(BOARD).o
 COBJS-$(CONFIG_CMD_IDE) += ../common/cfide.o
 COBJS-$(CONFIG_EPLED) += ../common/epled.o
+COBJS-$(CONFIG_GPIO) += gpio.o
 COBJS-$(CONFIG_SEVENSEG) += ../common/sevenseg.o
 
 SOBJS-y	:= text_base.o

board/altera/nios2-generic/gpio.c

@@ -0,0 +1,55 @@
+/*
+ * board gpio driver
+ *
+ * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
+ * Licensed under the GPL-2 or later.
+ */
+#include <common.h>
+#include <asm/io.h>
+
+#ifndef CONFIG_SYS_GPIO_BASE
+
+#define ALTERA_PIO_BASE LED_PIO_BASE
+#define ALTERA_PIO_DATA (ALTERA_PIO_BASE + 0)
+#define ALTERA_PIO_DIR (ALTERA_PIO_BASE + 4)
+static u32 pio_data_reg;
+static u32 pio_dir_reg;
+
+int gpio_direction_input(unsigned gpio)
+{
+	u32 mask = 1 << gpio;
+	writel(pio_dir_reg &= ~mask, ALTERA_PIO_DIR);
+	return 0;
+}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+	u32 mask = 1 << gpio;
+	if (value)
+		pio_data_reg |= mask;
+	else
+		pio_data_reg &= ~mask;
+	writel(pio_data_reg, ALTERA_PIO_DATA);
+	writel(pio_dir_reg |= mask, ALTERA_PIO_DIR);
+	return 0;
+}
+
+int gpio_get_value(unsigned gpio)
+{
+	u32 mask = 1 << gpio;
+	if (pio_dir_reg & mask)
+		return (pio_data_reg & mask) ? 1 : 0;
+	else
+		return (readl(ALTERA_PIO_DATA) & mask) ? 1 : 0;
+}
+
+void gpio_set_value(unsigned gpio, int value)
+{
+	u32 mask = 1 << gpio;
+	if (value)
+		pio_data_reg |= mask;
+	else
+		pio_data_reg &= ~mask;
+	writel(pio_data_reg, ALTERA_PIO_DATA);
+}
+#endif

include/configs/nios2-generic.h

@@ -63,10 +63,10 @@
  * STATUS LED
  */
 #define CONFIG_STATUS_LED		/* Enable status driver */
-#define CONFIG_EPLED			/* Enable LED PIO driver */
+#define CONFIG_GPIO_LED		/* Enable GPIO LED driver */
-#define CONFIG_SYS_LEDPIO_ADDR		LED_PIO_BASE
+#define CONFIG_GPIO			/* Enable GPIO driver */
 
-#define STATUS_LED_BIT			1	/* Bit-0 on PIO */
+#define STATUS_LED_BIT			0	/* Bit-0 on GPIO */
 #define STATUS_LED_STATE		1	/* Blinking */
 #define STATUS_LED_PERIOD	(500 / CONFIG_SYS_NIOS_TMRMS) /* 500 msec */