回答編集履歴

I2Cダンプ関数追加

2019/09/06 10:43

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -226,6 +226,44 @@
 }
+int i2c_dump16(u8 slave_addr, u16 reg, u32 in_len)
+{
+    u8 out[2] = { (u8)(reg >> 8), (u8)reg};
+    u8 in[256];
+    u32 i;
+    int retval;
+    if(in_len > sizeof(in)) { in_len = sizeof(in); }
+    for(i = 0;i < in_len;i++) { in[i] = 0xaa; }
+    retval = i2c_rw(slave_addr, out, sizeof(out), in , in_len);
+    if(retval >= 0){
+        for(i = 0;i < in_len;i++){
+            if ((i & 0xf) ==0) { printf("%04x:", reg + i); }
+            printf("%02x%c", in[i], ((i & 0xf) == 0xf) ? '\n' : ' ');
+        }
+        if ((i & 0xf) !=0) { printf("\n"); }
+    }
+    return retval;
+}
 ```

使用例の誤り修正

2019/09/06 10:42

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -274,7 +274,7 @@
     u16 data16;
-    retval = i2c_read16_8(BH1750_ADDRESS, /*RESULT__ALS_VAL*/0x50, &data16);
+    retval = i2c_read16_16(BH1750_ADDRESS, /*RESULT__ALS_VAL*/0x50, &data16);
     if(retval < 0){

使用例を追加

2019/09/05 18:34

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -231,3 +231,65 @@
 好きに使ってください。
+使用例
+```C
+// For 8bit registers
+{
+    int retval;
+    u8 data8;
+    retval = i2c_read16_8(BH1750_ADDRESS, /*RESULT__INTERRUPT_STATUS_GPIO*/0x4f, &data8);
+    if(retval < 0){
+        /* エラー処理:適切な処理を入れてください */
+    }
+    else {
+        /* 正常時処理 */
+        printf("register value = %02x\n", data8);
+    }
+}
+// for 16bit registers
+{
+    int retval;
+    u16 data16;
+    retval = i2c_read16_8(BH1750_ADDRESS, /*RESULT__ALS_VAL*/0x50, &data16);
+    if(retval < 0){
+        /* エラー処理:適切な処理を入れてください */
+    }
+    else {
+        /* 正常時処理 */
+        printf("register value = %04x\n", data16);
+    }
+}
+```

不具合修正

2019/09/05 17:24

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -148,7 +148,7 @@
-        msgset.nmsgs = 1;
+        msgset.nmsgs = 2;
     }

ソースコードを更新。レジスタ幅16bit、データ幅8bit/16bit両対応

2019/09/04 22:08

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -26,7 +26,7 @@
-[これ](https://gist.github.com/JamesDunne/9b7fbedb74c22ccc833059623f47beb7)をベースに
+[これ](https://gist.github.com/JamesDunne/9b7fbedb74c22ccc833059623f47beb7)を参考に実装します。
@@ -34,130 +34,200 @@
+```C
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <linux/i2c-dev.h>
+#ifndef I2C_M_RD
+#include <linux/i2c.h>
+#endif
+typedef unsigned char   u8;
+typedef unsigned short  u16;
+typedef unsigned int    u32;
+int i2c_fd = -1;
+const char *i2c_fname = "/dev/i2c-1";
+int i2c_init(void)
+{
+    if ((i2c_fd = open(i2c_fname, O_RDWR)) < 0) {
+        char err[200];
+        sprintf(err, "open('%s') in i2c_init", i2c_fname);
+        perror(err);
+        return -1;
+    }
+    return i2c_fd;
+}
+void i2c_close(void)
+{
+    close(i2c_fd);
+    i2c_fd = -1;
+}
+int i2c_rw(u8 slave_addr, u8 *out, u32 out_len, u8 *in, u32 in_len)
+{
+    int retval;
+    struct i2c_msg msgs[2];
+    struct i2c_rdwr_ioctl_data msgset;
+    msgset.msgs = msgs;
+    msgset.nmsgs = 1;
+    msgs[0].addr = slave_addr;
+    msgs[0].flags = 0;
+    msgs[0].len = out_len;
+    msgs[0].buf = out;
+    if(in_len > 0U){
+        msgs[1].addr = slave_addr;
+        msgs[1].flags = I2C_M_RD | I2C_M_NOSTART;
+        msgs[1].len = in_len;
+        msgs[1].buf = in;
+        msgset.nmsgs = 1;
+    }
+    if (ioctl(i2c_fd, I2C_RDWR, &msgset) < 0) {
+        perror("ioctl(I2C_RDWR) in i2c_rw");
+        return -1;
+    }
+    return 0;
+}
+int i2c_write16_8(u8 slave_addr, u16 reg, u8 data)
+{
+    u8 out[3] = { (u8)(reg >> 8), (u8)reg, data };
+    return i2c_rw(slave_addr, out, sizeof(out), NULL, 0);
+}
+int i2c_write16_16(u8 slave_addr, u16 reg, u16 data)
+{
+    u8 out[4] = { (u8)(reg >> 8), (u8)reg, (u8)(data >> 8), (u8)data };
+    return i2c_rw(slave_addr, out, sizeof(out), NULL, 0);
+}
+int i2c_read16_8(u8 slave_addr, u16 reg, u8 *data)
+{
+    u8 out[2] = { (u8)(reg >> 8), (u8)reg};
+    return i2c_rw(slave_addr, out, sizeof(out), data, 1);
+}
+int i2c_read16_16(u8 slave_addr, u16 reg, u16 *data)
+{
+    u8 out[2] = { (u8)(reg >> 8), (u8)reg};
+    u8 in[2];
+    int retval = i2c_rw(slave_addr, out, sizeof(out), in, sizeof(in));
+    if(retval >= 0){
+        *data = (((u16)in[0]) << 8) | in[1];
+    }
+    return retval;
+}
 ```
-// Write to an I2C slave device's register:
-int i2c_write(u8 slave_addr, u16 reg, u8 data) {
-    int retval;
+好きに使ってください。
-    u8 outbuf[3];
-    struct i2c_msg msgs[1];
-    struct i2c_rdwr_ioctl_data msgset[1];
-    outbuf[0] = (reg >> 8) & 0xffU;
-    outbuf[1] = (reg >> 0) & 0xffU;
-    outbuf[2] = data;
-    msgs[0].addr = slave_addr;
-    msgs[0].flags = 0;
-    msgs[0].len = 3;
-    msgs[0].buf = outbuf;
-    msgset[0].msgs = msgs;
-    msgset[0].nmsgs = 1;
-    if (ioctl(i2c_fd, I2C_RDWR, &msgset) < 0) {
-        perror("ioctl(I2C_RDWR) in i2c_write");
-        return -1;
-    }
-    return 0;
-}
-// Read the given I2C slave device's register and return the read value in `*result`:
-int i2c_read(u8 slave_addr, u16 reg, u8 *result) {
-    int retval;
-    u8 outbuf[2], inbuf[1];
-    struct i2c_msg msgs[2];
-    struct i2c_rdwr_ioctl_data msgset[1];
-    msgs[0].addr = slave_addr;
-    msgs[0].flags = 0;
-    msgs[0].len = 1;
-    msgs[0].buf = outbuf;
-    msgs[1].addr = slave_addr;
-    msgs[1].flags = I2C_M_RD | I2C_M_NOSTART;
-    msgs[1].len = 1;
-    msgs[1].buf = inbuf;
-    msgset[0].msgs = msgs;
-    msgset[0].nmsgs = 2;
-    outbuf[0] = (reg >> 8) & 0xffU;
-    outbuf[1] = (reg >> 0) & 0xffU;
-    inbuf[0] = 0;
-    *result = 0;
-    if (ioctl(i2c_fd, I2C_RDWR, &msgset) < 0) {
-        perror("ioctl(I2C_RDWR) in i2c_read");
-        return -1;
-    }
-    *result = inbuf[0];
-    return 0;
-}
-```

修正漏れ対応

2019/09/04 22:00

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -94,7 +94,7 @@
 // Read the given I2C slave device's register and return the read value in `*result`:
-int i2c_read(u8 slave_addr, u8 reg, u8 *result) {
+int i2c_read(u8 slave_addr, u16 reg, u8 *result) {
     int retval;

リンクの書き方を修正

2019/09/04 13:30

投稿

nomuken

スコア1627

test CHANGED Viewed

@@ -12,7 +12,7 @@
-そして(wiringPiI2C*の実装)[https://github.com/WiringPi/WiringPi/blob/master/wiringPi/wiringPiI2C.c]を見たのですがLinux KernelのSMBusインタフェースを使用して実装されています。
+そして[wiringPiI2C*の実装](https://github.com/WiringPi/WiringPi/blob/master/wiringPi/wiringPiI2C.c)を見たのですがLinux KernelのSMBusインタフェースを使用して実装されています。