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>
diff --git a/board/altera/nios2-generic/gpio.c b/board/altera/nios2-generic/gpio.c
new file mode 100644
index 0000000..6c9c6c2
--- /dev/null
+++ b/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