i2cdetect: don't die on addresses already in use by drivers

We can't use i2c_set_slave_addr() in i2cdetect, as we have to check for
EBUSY after calling ioctl(I2C_SLAVE) and print 'UU' on busy addresses
instead of bailing-out.

While we're at it: reorder definitions of local vars in i2cdetect_main().

function                                             old     new   delta
i2cdetect_main                                       703     744     +41
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/0 up/down: 41/0)               Total: 41 bytes
   text	   data	    bss	    dec	    hex	filename
 826097	   4164	   9584	 839845	  cd0a5	busybox_old
 826145	   4164	   9584	 839893	  cd0d5	busybox_unstripped

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

1 files changed, 19 insertions, 12 deletions

diff --git a/miscutils/i2c_tools.c b/miscutils/i2c_tools.c
index 7034dc9a8..d5127ec27 100644
--- a/miscutils/i2c_tools.c
+++ b/miscutils/i2c_tools.c
@@ -355,6 +355,13 @@ static void i2c_set_pec(int fd, int pec)
                                 itoptr(pec ? 1 : 0),
                                 "can't set PEC");
 }
+
+static void i2c_set_slave_addr(int fd, int addr, int force)
+{
+        ioctl_or_perror_and_die(fd, force ? I2C_SLAVE_FORCE : I2C_SLAVE,
+                                itoptr(addr),
+                                "can't set address to 0x%02x", addr);
+}
 #endif /* ENABLE_I2CGET || ENABLE_I2CSET || ENABLE_I2CDUMP */
 
 #if ENABLE_I2CGET || ENABLE_I2CSET
@@ -390,13 +397,6 @@ static int i2c_dev_open(int i2cbus)
         return fd;
 }
 
-static void i2c_set_slave_addr(int fd, int addr, int force)
-{
-        ioctl_or_perror_and_die(fd, force ? I2C_SLAVE_FORCE : I2C_SLAVE,
-                                itoptr(addr),
-                                "can't set address to 0x%02x", addr);
-}
-
 /* Size reducing helpers for xxx_check_funcs(). */
 static void get_funcs_matrix(int fd, unsigned long *funcs)
 {
@@ -1281,11 +1281,9 @@ 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 = DETECT_MODE_AUTO;
-        int status;
-        unsigned first = 0x00, last = 0x77;
+        int fd, bus_num, i, j, mode = DETECT_MODE_AUTO, status;
+        unsigned first = 0x00, last = 0x77, opts;
         unsigned long funcs;
-        unsigned opts;
 
         opt_complementary = "q--r:r--q:" /* mutually exclusive */
                         "?3"; /* up to 3 args */
@@ -1370,7 +1368,16 @@ int i2cdetect_main(int argc UNUSED_PARAM, char **argv)
                                 continue;
                         }
 
-                        i2c_set_slave_addr(fd, i + j, 0);
+                        status = ioctl(fd, I2C_SLAVE, itoptr(i + j));
+                        if (status < 0) {
+                                if (errno == EBUSY) {
+                                        printf("UU ");
+                                        continue;
+                                }
+
+                                bb_perror_msg_and_die(
+                                        "can't set address to 0x%02x", i + j);
+                        }
 
                         switch (mode) {
                         case DETECT_MODE_READ: