i2cdump: display the numeric value for block read ioctl() errors

This makes busybox i2cdump compatible with the upstream version, which
also displays the numeric error value in case of a block read failure.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/miscutils/i2c_tools.c b/miscutils/i2c_tools.c
index 7be489036..e19d851fe 100644
--- a/miscutils/i2c_tools.c
+++ b/miscutils/i2c_tools.c
@@ -732,8 +732,10 @@ static int read_block_data(int buf_fd, int mode, int *block)
                         tmp = i2c_smbus_read_i2c_block_data(
                                         buf_fd, res, I2C_SMBUS_BLOCK_MAX,
                                         cblock + res);
-                        if (tmp <= 0)
+                        if (tmp <= 0) {
+                                blen = tmp;
                                 goto fail;
+                        }
                 }
 
                 if (res >= I2CDUMP_NUM_REGS)
@@ -750,7 +752,7 @@ static int read_block_data(int buf_fd, int mode, int *block)
         return blen;
 
  fail:
-        bb_error_msg_and_die("block read failed");
+        bb_error_msg_and_die("block read failed: %d", blen);
 }
 
 /* Dump all but word data. */