[PATCH 1/6] i2cdetect: fix address skipping in auto mode

Bartosz Golaszewski bartekgola at gmail.com
Tue Oct 27 16:15:00 UTC 2015


If the bus doesn't support SMBus Quick Write or Receive Byte commands
and we're running in auto mode all addresses will be skipped resulting
in an empty table being printed.

This is caused by not restoring the auto mode after it's been changed
for certain address ranges - we need an additional variable to hold the
temporary state.

Signed-off-by: Bartosz Golaszewski <bartekgola at gmail.com>
---
 miscutils/i2c_tools.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/miscutils/i2c_tools.c b/miscutils/i2c_tools.c
index d77e6ba..c5baaa7 100644
--- a/miscutils/i2c_tools.c
+++ b/miscutils/i2c_tools.c
@@ -1200,7 +1200,7 @@ int i2cdetect_main(int argc UNUSED_PARAM, char **argv)
 			      opt_F = (1 << 4), opt_l = (1 << 5);
 	const char *const optstr = "yaqrFl";
 
-	int fd, bus_num, i, j, mode = I2CDETECT_MODE_AUTO, status;
+	int fd, bus_num, i, j, mode = I2CDETECT_MODE_AUTO, status, cmd;
 	unsigned first = 0x03, last = 0x77, opts;
 	unsigned long funcs;
 
@@ -1273,19 +1273,20 @@ int i2cdetect_main(int argc UNUSED_PARAM, char **argv)
 		for(j = 0; j < 16; j++) {
 			fflush_all();
 
+			cmd = mode;
 			if (mode == I2CDETECT_MODE_AUTO) {
 				if ((i+j >= 0x30 && i+j <= 0x37) ||
 				    (i+j >= 0x50 && i+j <= 0x5F))
-					mode = I2CDETECT_MODE_READ;
+					cmd = I2CDETECT_MODE_READ;
 				else
-					mode = I2CDETECT_MODE_QUICK;
+					cmd = I2CDETECT_MODE_QUICK;
 			}
 
 			/* Skip unwanted addresses. */
 			if (i+j < first
 			 || i+j > last
-			 || (mode == I2CDETECT_MODE_READ && !(funcs & I2C_FUNC_SMBUS_READ_BYTE))
-			 || (mode == I2CDETECT_MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_QUICK)))
+			 || (cmd == I2CDETECT_MODE_READ && !(funcs & I2C_FUNC_SMBUS_READ_BYTE))
+			 || (cmd == I2CDETECT_MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_QUICK)))
 			{
 				printf("   ");
 				continue;
@@ -1302,7 +1303,7 @@ int i2cdetect_main(int argc UNUSED_PARAM, char **argv)
 					"can't set address to 0x%02x", i + j);
 			}
 
-			switch (mode) {
+			switch (cmd) {
 			case I2CDETECT_MODE_READ:
 				/*
 				 * This is known to lock SMBus on various
-- 
2.1.4



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