From 9ca61be337f7c9738f446d5dbc92df594d85f16f Mon Sep 17 00:00:00 2001
From: shuixx <shuixx@shuixx.com>
Date: Mon, 10 Jun 2019 20:34:40 +0800
Subject: [PATCH] add mutex lock

---
 ds18b20.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/ds18b20.c b/ds18b20.c
index a820f09..20083ba 100755
--- a/ds18b20.c
+++ b/ds18b20.c
@@ -4,6 +4,7 @@
 #include <linux/slab.h>
 #include <linux/ioctl.h>
 #include <linux/delay.h>
+#include <linux/mutex.h>
 
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
@@ -17,7 +18,9 @@ unsigned int gpio_num = 0;
 #define DQ_L gpio_set_value(gpio_num, 0)
 #define DQ_V gpio_get_value(gpio_num)
 
-spinlock_t lock;
+//spinlock_t lock;
+//#define DEFINE_MUTEX(LOCK)
+struct mutex mutex;
 
 //********************************
 //功能:ds18b20复位
@@ -33,7 +36,7 @@ int init_DS18B20(void)
 	udelay(65);
 	result = DQ_V;
 	udelay(240);
-    printk("ds18b20 init result %d,%d", result, DQ_V);
+    //printk("ds18b20 init result %d,%d", result, DQ_V);
 	udelay(180);
     return result;
 }
@@ -46,7 +49,7 @@ unsigned char read_char(void)
     unsigned int i = 0;
     unsigned char dat = 0;
 
-    spin_lock(&lock);
+  //  spin_lock(&lock);
 	DQ_OUT;
     for(i=0; i<8; i++) {
 		DQ_L;
@@ -60,7 +63,7 @@ unsigned char read_char(void)
 		DQ_OUT;
 		udelay(2);
     }
-    spin_unlock(&lock);
+    //spin_unlock(&lock);
     return dat;
 }
 
@@ -71,7 +74,7 @@ void write_char(unsigned char dat)
 {
     unsigned int i = 0;
 
-    spin_lock(&lock);
+    //spin_lock(&lock);
     DQ_OUT;
     for(i=0; i<8; i++) 
 	{
@@ -86,17 +89,14 @@ void write_char(unsigned char dat)
         udelay(2);
 		dat >>= 1;
     }
-    spin_unlock(&lock);
+    //spin_unlock(&lock);
 }
 
 int initDs18b20(unsigned int gpioNum)
 {
-    spin_lock_init(&lock);
     gpio_num = gpioNum;
-    if (init_DS18B20())
-    {
-        return 1;
-    }
+    //spin_lock_init(&lock);
+    mutex_init(&mutex);
     return 0;
 }
 
@@ -111,21 +111,33 @@ void readDs18b20Data(unsigned char *value)
     {
         return;
     }
+    mutex_lock(&mutex);
+//    local_irq_disable();
     if (init_DS18B20())
     {
+//        local_irq_enable();
+        mutex_unlock(&mutex);
         return;
     }
     write_char(0xCC);
     write_char(0x44);
 
+//    local_irq_enable();
+
     mdelay(750);
 
+//    local_irq_disable();
+
     if (init_DS18B20())
     {
+//        local_irq_enable();
+        mutex_unlock(&mutex);
         return;
     }
     write_char(0xCC);
     write_char(0xBE);
+//    local_irq_enable();
+    mutex_unlock(&mutex);
 
     value[0] = read_char();
     value[1] = read_char();