[PATCH v2 1/1] usb: typec: stusb160x: fix signedness comparison issue with enum variables

From: Amelie Delaunay
Date: Wed Oct 28 2020 - 17:44:24 EST


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@xxxxxxxxx>
Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx>
---
v2: Remove blank line
---
drivers/usb/typec/stusb160x.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/typec/stusb160x.c b/drivers/usb/typec/stusb160x.c
index da7f1957bcb3..2c6636e8535d 100644
--- 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;
--
2.17.1