powerpc/macintosh: Fix unsigned check in smu_sat_get_sdb_partition()

i2c_smbus_read_word_data() returns a s32, which may be negative
but unsigned len cannot be negative.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/macintosh/windfarm_smu_sat.c b/drivers/macintosh/windfarm_smu_sat.c
index 7f2be4baaeda..7847e981ac33 100644
--- a/drivers/macintosh/windfarm_smu_sat.c
+++ b/drivers/macintosh/windfarm_smu_sat.c
@@ -87,11 +87,12 @@ struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
                 return NULL;
         }
 
-        len = i2c_smbus_read_word_data(&sat->i2c, 9);
-        if (len < 0) {
+        err = i2c_smbus_read_word_data(&sat->i2c, 9);
+        if (err < 0) {
                 printk(KERN_ERR "smu_sat_get_sdb_part rd len error\n");
                 return NULL;
         }
+        len = err;
         if (len == 0) {
                 printk(KERN_ERR "smu_sat_get_sdb_part no partition %x\n", id);
                 return NULL;