From 6b01facc48e150781beeb1d42ad6436dc5e95af2 Mon Sep 17 00:00:00 2001
From: liangkangnan <liangkangnan@163.com>
Date: Sun, 14 Jun 2020 10:45:55 +0800
Subject: [PATCH] example: gpio: add input usage

Signed-off-by: liangkangnan <liangkangnan@163.com>
---
 tests/example/gpio/README.md |  2 +-
 tests/example/gpio/main.c    | 11 +++++++++--
 tests/example/include/gpio.h |  1 +
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/tests/example/gpio/README.md b/tests/example/gpio/README.md
index 6f6e00a..3337f1b 100644
--- a/tests/example/gpio/README.md
+++ b/tests/example/gpio/README.md
@@ -1 +1 @@
-通过一个GPIO来控制板上的LED以1Hz频率闪烁。
\ No newline at end of file
+两个GPIO，一个输入，一个输出。输出那个GPIO的输出电平等于输入那个GPIO的输入电平。
\ No newline at end of file
diff --git a/tests/example/gpio/main.c b/tests/example/gpio/main.c
index 97c8b22..2d4226b 100644
--- a/tests/example/gpio/main.c
+++ b/tests/example/gpio/main.c
@@ -6,8 +6,15 @@
 
 int main()
 {
+    GPIO_REG(GPIO_CTRL) |= 0x1;       // gpio0输出模式
+    GPIO_REG(GPIO_CTRL) |= 0x1 << 3;  // gpio1输入模式
+
     while (1) {
-        GPIO_REG(GPIO_DATA) ^= 0x1;
-        busy_wait(500 * 1000);  // delay 500ms
+        // 如果GPIO1输入高
+        if (GPIO_REG(GPIO_DATA) & 0x2)
+            GPIO_REG(GPIO_DATA) |= 0x1;  // GPIO0输出高
+        // 如果GPIO1输入低
+        else
+            GPIO_REG(GPIO_DATA) &= ~0x1; // GPIO0输出低
     }
 }
diff --git a/tests/example/include/gpio.h b/tests/example/include/gpio.h
index dbad864..f7f5829 100644
--- a/tests/example/include/gpio.h
+++ b/tests/example/include/gpio.h
@@ -2,6 +2,7 @@
 #define _GPIO_H_
 
 #define GPIO_BASE      (0x40000000)
+#define GPIO_CTRL      (GPIO_BASE + (0x00))
 #define GPIO_DATA      (GPIO_BASE + (0x04))
 
 #define GPIO_REG(addr) (*((volatile uint32_t *)addr))