From 6e64eec398bb853f26779d35aac89afadaa08fcf Mon Sep 17 00:00:00 2001
From: Bereket Guta <bereket17@hotmail.com>
Date: Sun, 27 Mar 2022 22:03:58 -0700
Subject: [PATCH] make reads non blocking and set device address once

---
 include/i2c/i2c.h |  2 +-
 src/i2c.c         | 27 ++++++++++++---------------
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
index b57f35e..59d2451 100644
--- a/include/i2c/i2c.h
+++ b/include/i2c/i2c.h
@@ -27,7 +27,7 @@ void i2c_close(int bus);
 int i2c_open(const char *bus_name);
 
 /* Initialize I2CDevice with default value */
-void i2c_init_device(I2CDevice *device);
+int i2c_init_device(I2CDevice *device);
 
 /* Get i2c device description */
 char *i2c_get_device_desc(const I2CDevice *device, char *buf, size_t size);
diff --git a/src/i2c.c b/src/i2c.c
index 2ce0d6e..cb10ea7 100644
--- a/src/i2c.c
+++ b/src/i2c.c
@@ -37,6 +37,9 @@ int i2c_open(const char *bus_name)
         return -1;
     }
 
+    // make reading non blocking
+    fcntl(fd, F_SETFL, O_NONBLOCK);
+
     return fd;
 }
 
@@ -51,7 +54,7 @@ void i2c_close(int bus)
 **	@brief		:	Initialize I2CDevice with defualt value
 **	#device	    :	I2CDevice struct
 */
-void i2c_init_device(I2CDevice *device)
+int i2c_init_device(I2CDevice *device)
 {
     /* 7 bit device address */
     device->tenbit = 0;
@@ -64,6 +67,12 @@ void i2c_init_device(I2CDevice *device)
 
     /* 1 byte internal(word) address */
     device->iaddr_bytes = 1;
+
+    /* Set i2c slave address once */
+    if (i2c_select(device->bus, device->addr, device->tenbit) == -1) {
+        return -1;
+    }
+    return 0;
 }
 
 
@@ -218,12 +227,6 @@ ssize_t i2c_read(const I2CDevice *device, unsigned int iaddr, void *buf, size_t
     unsigned char addr[INT_ADDR_MAX_BYTES];
     unsigned char delay = GET_I2C_DELAY(device->delay);
 
-    /* Set i2c slave address */
-    if (i2c_select(device->bus, device->addr, device->tenbit) == -1) {
-
-        return -1;
-    }
-
     /* Convert i2c internal address */
     memset(addr, 0, sizeof(addr));
     i2c_iaddr_convert(iaddr, device->iaddr_bytes, addr);
@@ -266,12 +269,6 @@ ssize_t i2c_write(const I2CDevice *device, unsigned int iaddr, const void *buf,
     unsigned char delay = GET_I2C_DELAY(device->delay);
     unsigned char tmp_buf[PAGE_MAX_BYTES + INT_ADDR_MAX_BYTES];
 
-    /* Set i2c slave address */
-    if (i2c_select(device->bus, device->addr, device->tenbit) == -1) {
-
-        return -1;
-    }
-
     /* Once only can write less than 4 byte */
     while (remain > 0) {
 
@@ -350,8 +347,8 @@ int i2c_select(int bus, unsigned long dev_addr, unsigned long tenbit)
         return -1;
     }
 
-    /* Set i2c device as slave ans set it address */
-    if (ioctl(bus, I2C_SLAVE, dev_addr)) {
+    /* Set i2c device as slave and set it address */
+    if (ioctl(bus, I2C_SLAVE_FORCE, dev_addr)) {
 
         perror("Set i2c device address failed");
         return -1;