From d03f549fa5327ff2e138547e702877cb12a82189 Mon Sep 17 00:00:00 2001
From: guowenxue <guowenxue@gmail.com>
Date: Sat, 22 Nov 2025 20:24:56 +0800
Subject: [PATCH] update TSL2561 source code to fix bug

---
 utils/tsl2561.c |  109 ++++++++++++++++++++++++++++++++----------------------
 1 files changed, 64 insertions(+), 45 deletions(-)

diff --git a/utils/tsl2561.c b/utils/tsl2561.c
index 20bd0c2..d21dc32 100644
--- a/utils/tsl2561.c
+++ b/utils/tsl2561.c
@@ -63,7 +63,7 @@
 
 static const int  regs_addr[REG_COUNT]={DATA0LOW, DATA0HIGH, DATA1LOW, DATA1HIGH};
 
-float tsl2561_get_lux(int fd);
+int tsl2561_get_lux(char *dev, float *lux);
 static inline void print_datime(void);
 
 static inline void banner(const char *progname)
@@ -89,7 +89,7 @@
 
 int main(int argc, char **argv)
 {
-    int             fd, rv;
+    int             rv;
     float           lux;
     char           *dev = "/dev/i2c-0";
     char           *progname=NULL;
@@ -125,26 +125,17 @@
         }
     }
 
-    /*+--------------------------------+
-     *|     open /dev/i2c-x device     |
-     *+--------------------------------+*/
-    if( (fd=open(dev, O_RDWR)) < 0)
-    {
-        printf("i2c device '%s' open failed: %s\n", dev, strerror(errno));
-        return -1;
-    }
-
     while(1)
     {
-        lux = tsl2561_get_lux(fd);
-
-        print_datime();
-        printf("TSLl2561 get lux: %.3f\n", lux);
+        if( !tsl2561_get_lux(dev, &lux) )
+        {
+            print_datime();
+            printf("TSLl2561 get lux: %.3f\n", lux);
+        }
 
         sleep(1);
     }
 
-    close(fd);
     return 0;
 }
 
@@ -260,17 +251,27 @@
     return 0;
 }
 
-float tsl2561_get_lux(int fd)
+int tsl2561_get_lux(char *dev, float *lux)
 {
-    int                 i;
+    int                 i, fd;
+    int                 rv = 0;
+
     unsigned char       reg_data[REG_COUNT];
-    unsigned char       buf;
+    int                 ch0_data = 0;
+    int                 ch1_data = 0;
+    float               ratio = 0.0;
 
-    int                 chn0_data = 0;
-    int                 chn1_data = 0;
+    if( !lux )
+    {
+        printf("Invalid input arguments\n");
+        return -1;
+    }
 
-    float               div = 0.0;
-    float               lux = 0.0;
+    if( (fd=open(dev, O_RDWR)) < 0)
+    {
+        printf("i2c device '%s' open failed: %s\n", dev, strerror(errno));
+        return -2;
+    }
 
     tsl2561_power(fd, ON);
 
@@ -279,38 +280,56 @@
     /* Read register Channel0 and channel1 data from register */
     for(i=0; i<REG_COUNT; i++)
     {
-        tsl2561_readreg(fd, regs_addr[i], &reg_data[i]);
+        rv = tsl2561_readreg(fd, regs_addr[i], &reg_data[i]);
+        if( rv < 0)
+        {
+            printf("TSL2561 read register failed\n");
+            goto cleanup;
+        }
     }
 
-    chn0_data = reg_data[1]*256 + reg_data[0]; /* Channel0 = DATA0HIGH<<8 + DATA0LOW  */
-    chn1_data = reg_data[3]*256 + reg_data[2]; /* channel1 = DATA1HIGH<<8 +  DATA1LOW */
+    rv = 0;
+    ch0_data = (reg_data[1]<<8) + reg_data[0]; /* 通道0：可见光+红外 */
+    ch1_data = (reg_data[3]<<8) + reg_data[2]; /* 通道1：仅红外 */
 
-    if( chn0_data<=0 || chn1_data<0 )
-    {
-        lux = 0.0;
-        goto OUT;
+
+    /* 根据datasheet，饱和时光照强度很大 */
+    if (ch0_data == 0xFFFF || ch1_data == 0xFFFF) {
+        *lux = 50000.0;
+        goto cleanup;
     }
 
-    div = (float)chn1_data / (float)chn0_data;
+    if (ch0_data == 0) { /* 无光照 */
+        *lux = 0.0;
+        goto cleanup;
+    }
 
-    if( div>0 && div<=0.5 )
-        lux = 0.304*chn0_data-0.062*chn0_data*pow(div,1.4);
+    ratio = (float)ch1_data / (float)ch0_data;
 
-    else if( div>0.5 && div<=0.61 )
-        lux = 0.0224*chn0_data-0.031*chn1_data;
+    if (ratio >= 0 && ratio <= 0.50) {
+        *lux = 0.0304f * ch0_data - 0.062f * ch0_data * powf(ratio, 1.4f);
+    }
+    else if (ratio <= 0.61) {
+        *lux = 0.0224f * ch0_data - 0.031f * ch1_data;
+    }
+    else if (ratio <= 0.80) {
+        *lux = 0.0128f * ch0_data - 0.0153f * ch1_data;
+    }
+    else if (ratio <= 1.30) {
+        *lux = 0.00146f * ch0_data - 0.00112f * ch1_data;
+    }
+    else { /* 超出有效范围 */
+        *lux = 0.0;
+    }
 
-    else if( div>0.61 && div<=0.8 )
-        lux = 0.0128*chn0_data-0.0153*chn1_data;
+    if (*lux < 0) { /* 确保结果非负 */
+        *lux = 0.0;
+    }
 
-    else if( div>0.8 && div<=1.3 )
-        lux = 0.00146*chn0_data-0.00112*chn1_data;
-
-    else if( div>1.3 )
-        lux = 0.0;
-
-OUT:
+cleanup:
     tsl2561_power(fd, OFF);
-    return lux;
+    close(fd);
+    return rv;
 }
 
 static inline void dump_buf(const char *prompt, char *buf, int size)

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