From 681e2e2674cf6c0639a403286241bdbd00e24236 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Sun, 28 Jul 2013 23:25:47 +0200
Subject: add vusb-i2cget

---
 commandline/Makefile   |  6 +++++-
 commandline/i2c-util.c | 18 ++++++++++++++++++
 commandline/i2c-util.h |  1 +
 commandline/i2cget.c   | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 commandline/i2cget.c

diff --git a/commandline/Makefile b/commandline/Makefile
index a4d0792..587f86c 100644
--- a/commandline/Makefile
+++ b/commandline/Makefile
@@ -9,7 +9,7 @@ LIBS      = $(USBLIBS)
 PREFIX ?= /usr/local
 bin_dir = ${DESTDIR}${PREFIX}/bin
 
-PROGRAMS = vusb-i2c vusb-i2cdetect vusb-i2cwrite
+PROGRAMS = vusb-i2c vusb-i2cdetect vusb-i2cwrite vusb-i2cget
 
 all: $(PROGRAMS)
 
@@ -20,6 +20,7 @@ i2c.o: i2c.c i2c-util.c i2c-util.h
 i2c-util.o: i2c-util.c
 i2cdetect.o: i2cdetect.c i2c-util.c i2c-util.h
 i2cwrite.o: i2cwrite.c i2c-util.c i2c-util.h
+i2cget.o: i2cget.c i2c-util.c i2c-util.h
 
 vusb-i2c: i2c.o i2c-util.o
 	$(CC) -o $@ $^ $(LIBS)
@@ -30,6 +31,9 @@ vusb-i2cdetect: i2cdetect.o i2c-util.o
 vusb-i2cwrite: i2cwrite.o i2c-util.o
 	$(CC) -o $@ $^ $(LIBS)
 
+vusb-i2cget: i2cget.o i2c-util.o
+	$(CC) -o $@ $^ $(LIBS)
+
 clean:
 	rm -f *.o $(PROGRAMS)
 
diff --git a/commandline/i2c-util.c b/commandline/i2c-util.c
index 3971721..2771a4e 100644
--- a/commandline/i2c-util.c
+++ b/commandline/i2c-util.c
@@ -267,6 +267,24 @@ unsigned char i2c_tx_byte(unsigned char byte)
 	return ack;
 }
 
+unsigned char i2c_rx_byte()
+{
+	signed char i;
+	unsigned char ret = 0;
+
+	set_sda(1);
+	for (i = 7; i >= -1; i--) {
+		set_scl(1);
+		usleep(10);
+		if ((i >= 0) && ( get_status() & (1 << BIT_SDA)))
+			ret |= (1 << i);
+		set_scl(0);
+		usleep(10);
+	}
+
+	return ret;
+}
+
 void i2c_start()
 {
 	set_sda(1);
diff --git a/commandline/i2c-util.h b/commandline/i2c-util.h
index 2b2f57b..4cd4919 100644
--- a/commandline/i2c-util.h
+++ b/commandline/i2c-util.h
@@ -11,6 +11,7 @@ void set_scl(char value);
 
 unsigned char get_status();
 unsigned char i2c_tx_byte(unsigned char byte);
+unsigned char i2c_rx_byte();
 
 void i2c_start();
 void i2c_stop();
diff --git a/commandline/i2cget.c b/commandline/i2cget.c
new file mode 100644
index 0000000..ed453ac
--- /dev/null
+++ b/commandline/i2cget.c
@@ -0,0 +1,34 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "i2c-util.h"
+
+int main(int argc, char **argv)
+{
+	int address, command;
+	unsigned char ret;
+
+	i2c_init();
+	i2c_start();
+
+	if (argc < 3) {
+		fputs("Usage: vusb-i2cget <address> <register>", stderr);
+		return 1;
+	}
+
+	address = atoi(argv[1]);
+	command = atoi(argv[2]);
+	i2c_tx_byte((address << 1) | 0);
+	i2c_tx_byte(command);
+	i2c_start();
+	i2c_tx_byte((address << 1) | 1);
+	ret = i2c_rx_byte();
+
+	i2c_stop();
+	i2c_deinit();
+
+	printf("%i\n", ret);
+
+	return 0;
+}
-- 
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