Enable full 64-byte page writes with direct I2C access

24cXX.c

@@ -52,12 +52,20 @@ static int i2c_write_2b(struct eeprom *e, __u8 buf[2])
 static int i2c_write_arbitrary(struct eeprom *e, __u8 *buf, int len)
 {
 	int r;
-        // we must simulate a plain I2C byte write with SMBus functions
-	r = i2c_smbus_write_i2c_block_data(e->fd, buf[0], len-1, buf+1);
-	if(r < 0)
+	if (ioctl(e->fd, I2C_SLAVE, e->addr) < 0) {
 		fprintf(stderr, "Error i2c_write_arbitrary: %s\n", strerror(errno));
-	usleep(10);
-	return r;
+		return -1;
+	}
+	r = write(e->fd, buf, len);
+	if (r < 0) {
+		fprintf(stderr, "Error i2c_write_arbitrary: %s\n", strerror(errno));
+		return r;
+	}
+	if (r != len) {
+		fprintf(stderr, "Error i2c_write_arbitrary: short write (%d of %d expected)\n", r, len);
+		return -1;
+	}
+	return 0;
 }
 
 

24cXX.h

@@ -23,9 +23,7 @@
 #define EEPROM_TYPE_8BIT_ADDR	1
 #define EEPROM_TYPE_16BIT_ADDR 	2
 
-// SMBus is limited to 32 bytes
-// Unfortunately, the 16-bit addressing on the EEPROM chews up one of those bytes, and further downgrades the max transfer size to 16 bytes of data (since we have to stay power of 2 aligned)
-#define MAX_PAGE_SIZE 16
+#define MAX_PAGE_SIZE 64
 
 struct eeprom
 {