usb: typec: stusb160x: fix signedness comparison issue with enum variables

chip->port_type and chip->pwr_opmode are enums and when GCC considers them
as unsigned, the conditions are never met.
This patch takes advantage of the ret variable and fixes the following
warnings:
drivers/usb/typec/stusb160x.c:548 stusb160x_get_fw_caps() warn: unsigned 'chip->port_type' is never less than zero.
drivers/usb/typec/stusb160x.c:570 stusb160x_get_fw_caps() warn: unsigned 'chip->pwr_opmode' is never less than zero.

Fixes: da0cb6310094 ("usb: typec: add support for STUSB160x Type-C controller family")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20201028163309.12878-1-amelie.delaunay@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/stusb160x.c b/drivers/usb/typec/stusb160x.c
index 4207669..2a618f0 100644 (file)
--- a/drivers/usb/typec/stusb160x.c
+++ b/drivers/usb/typec/stusb160x.c
@@ -544,11 +544,10 @@ static int stusb160x_get_fw_caps(struct stusb160x *chip,
         */
        ret = fwnode_property_read_string(fwnode, "power-role", &cap_str);
        if (!ret) {
-               chip->port_type = typec_find_port_power_role(cap_str);
-               if ((int)chip->port_type < 0) {
-                       ret = chip->port_type;
+               ret = typec_find_port_power_role(cap_str);
+               if (ret < 0)
                        return ret;
-               }
+               chip->port_type = ret;
        }
        chip->capability.type = chip->port_type;
 
@@ -565,16 +564,13 @@ static int stusb160x_get_fw_caps(struct stusb160x *chip,
         */
        ret = fwnode_property_read_string(fwnode, "power-opmode", &cap_str);
        if (!ret) {
-               chip->pwr_opmode = typec_find_pwr_opmode(cap_str);
+               ret = typec_find_pwr_opmode(cap_str);
                /* Power delivery not yet supported */
-               if ((int)chip->pwr_opmode < 0 ||
-                   chip->pwr_opmode == TYPEC_PWR_MODE_PD) {
-                       ret = (int)chip->pwr_opmode < 0 ? chip->pwr_opmode :
-                                                         -EINVAL;
-                       dev_err(chip->dev, "bad power operation mode: %d\n",
-                               chip->pwr_opmode);
-                       return ret;
+               if (ret < 0 || ret == TYPEC_PWR_MODE_PD) {
+                       dev_err(chip->dev, "bad power operation mode: %d\n", ret);
+                       return -EINVAL;
                }
+               chip->pwr_opmode = ret;
        }
 
        return 0;