[drm-misc:for-linux-next 7/10] drivers/gpu/drm/bridge/tc358775.c:544:7: warning: variable 'dsi_lanes' is used uninitialized whenever 'if' condition is false

From: kernel test robot
Date: Sun Jun 12 2022 - 08:39:13 EST

tree: git://anongit.freedesktop.org/drm/drm-misc for-linux-next
head: d643daaf1694b7565fbe3982b630e1c7b95f1600
commit: 56426faa1492289ff794620c4ed8c1847a420d0a [7/10] drm/bridge: tc358775: Convert to drm_of_get_data_lanes_count_ep
config: hexagon-randconfig-r045-20220612 (https://download.01.org/0day-ci/archive/20220612/202206122022.NpZvuwCU-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 6466c9abf3674bade1f6ee859f24ebc7aaf9cd88)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
git remote add drm-misc git://anongit.freedesktop.org/drm/drm-misc
git fetch --no-tags drm-misc for-linux-next
git checkout 56426faa1492289ff794620c4ed8c1847a420d0a
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/gpu/drm/bridge/ drivers/gpu/drm/msm/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/bridge/tc358775.c:544:7: warning: variable 'dsi_lanes' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (parent) {
^~~~~~
drivers/gpu/drm/bridge/tc358775.c:551:6: note: uninitialized use occurs here
if (dsi_lanes < 0)
^~~~~~~~~
drivers/gpu/drm/bridge/tc358775.c:544:3: note: remove the 'if' if its condition is always true
if (parent) {
^~~~~~~~~~~~
drivers/gpu/drm/bridge/tc358775.c:540:6: warning: variable 'dsi_lanes' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (endpoint) {
^~~~~~~~
drivers/gpu/drm/bridge/tc358775.c:551:6: note: uninitialized use occurs here
if (dsi_lanes < 0)
^~~~~~~~~
drivers/gpu/drm/bridge/tc358775.c:540:2: note: remove the 'if' if its condition is always true
if (endpoint) {
^~~~~~~~~~~~~~
drivers/gpu/drm/bridge/tc358775.c:532:15: note: initialize the variable 'dsi_lanes' to silence this warning
int dsi_lanes;
^
= 0
2 warnings generated.


vim +544 drivers/gpu/drm/bridge/tc358775.c

b26975593b17c2 Vinay Simha BN 2020-07-10 526
b26975593b17c2 Vinay Simha BN 2020-07-10 527 static int tc358775_parse_dt(struct device_node *np, struct tc_data *tc)
b26975593b17c2 Vinay Simha BN 2020-07-10 528 {
b26975593b17c2 Vinay Simha BN 2020-07-10 529 struct device_node *endpoint;
b26975593b17c2 Vinay Simha BN 2020-07-10 530 struct device_node *parent;
b26975593b17c2 Vinay Simha BN 2020-07-10 531 struct device_node *remote;
56426faa149228 Marek Vasut 2022-05-24 532 int dsi_lanes;
b26975593b17c2 Vinay Simha BN 2020-07-10 533
b26975593b17c2 Vinay Simha BN 2020-07-10 534 /*
b26975593b17c2 Vinay Simha BN 2020-07-10 535 * To get the data-lanes of dsi, we need to access the dsi0_out of port1
b26975593b17c2 Vinay Simha BN 2020-07-10 536 * of dsi0 endpoint from bridge port0 of d2l_in
b26975593b17c2 Vinay Simha BN 2020-07-10 537 */
b26975593b17c2 Vinay Simha BN 2020-07-10 538 endpoint = of_graph_get_endpoint_by_regs(tc->dev->of_node,
b26975593b17c2 Vinay Simha BN 2020-07-10 539 TC358775_DSI_IN, -1);
b26975593b17c2 Vinay Simha BN 2020-07-10 540 if (endpoint) {
b26975593b17c2 Vinay Simha BN 2020-07-10 541 /* dsi0_out node */
b26975593b17c2 Vinay Simha BN 2020-07-10 542 parent = of_graph_get_remote_port_parent(endpoint);
b26975593b17c2 Vinay Simha BN 2020-07-10 543 of_node_put(endpoint);
b26975593b17c2 Vinay Simha BN 2020-07-10 @544 if (parent) {
b26975593b17c2 Vinay Simha BN 2020-07-10 545 /* dsi0 port 1 */
56426faa149228 Marek Vasut 2022-05-24 546 dsi_lanes = drm_of_get_data_lanes_count_ep(parent, 1, -1, 1, 4);
b26975593b17c2 Vinay Simha BN 2020-07-10 547 of_node_put(parent);
b26975593b17c2 Vinay Simha BN 2020-07-10 548 }
b26975593b17c2 Vinay Simha BN 2020-07-10 549 }
b26975593b17c2 Vinay Simha BN 2020-07-10 550
56426faa149228 Marek Vasut 2022-05-24 551 if (dsi_lanes < 0)
56426faa149228 Marek Vasut 2022-05-24 552 return dsi_lanes;
b26975593b17c2 Vinay Simha BN 2020-07-10 553
56426faa149228 Marek Vasut 2022-05-24 554 tc->num_dsi_lanes = dsi_lanes;
b26975593b17c2 Vinay Simha BN 2020-07-10 555
b26975593b17c2 Vinay Simha BN 2020-07-10 556 tc->host_node = of_graph_get_remote_node(np, 0, 0);
b26975593b17c2 Vinay Simha BN 2020-07-10 557 if (!tc->host_node)
b26975593b17c2 Vinay Simha BN 2020-07-10 558 return -ENODEV;
b26975593b17c2 Vinay Simha BN 2020-07-10 559
b26975593b17c2 Vinay Simha BN 2020-07-10 560 of_node_put(tc->host_node);
b26975593b17c2 Vinay Simha BN 2020-07-10 561
b26975593b17c2 Vinay Simha BN 2020-07-10 562 tc->lvds_link = SINGLE_LINK;
b26975593b17c2 Vinay Simha BN 2020-07-10 563 endpoint = of_graph_get_endpoint_by_regs(tc->dev->of_node,
b26975593b17c2 Vinay Simha BN 2020-07-10 564 TC358775_LVDS_OUT1, -1);
b26975593b17c2 Vinay Simha BN 2020-07-10 565 if (endpoint) {
b26975593b17c2 Vinay Simha BN 2020-07-10 566 remote = of_graph_get_remote_port_parent(endpoint);
b26975593b17c2 Vinay Simha BN 2020-07-10 567 of_node_put(endpoint);
b26975593b17c2 Vinay Simha BN 2020-07-10 568
b26975593b17c2 Vinay Simha BN 2020-07-10 569 if (remote) {
b26975593b17c2 Vinay Simha BN 2020-07-10 570 if (of_device_is_available(remote))
b26975593b17c2 Vinay Simha BN 2020-07-10 571 tc->lvds_link = DUAL_LINK;
b26975593b17c2 Vinay Simha BN 2020-07-10 572 of_node_put(remote);
b26975593b17c2 Vinay Simha BN 2020-07-10 573 }
b26975593b17c2 Vinay Simha BN 2020-07-10 574 }
b26975593b17c2 Vinay Simha BN 2020-07-10 575
b26975593b17c2 Vinay Simha BN 2020-07-10 576 dev_dbg(tc->dev, "no.of dsi lanes: %d\n", tc->num_dsi_lanes);
b26975593b17c2 Vinay Simha BN 2020-07-10 577 dev_dbg(tc->dev, "operating in %d-link mode\n", tc->lvds_link);
b26975593b17c2 Vinay Simha BN 2020-07-10 578
b26975593b17c2 Vinay Simha BN 2020-07-10 579 return 0;
b26975593b17c2 Vinay Simha BN 2020-07-10 580 }
b26975593b17c2 Vinay Simha BN 2020-07-10 581

:::::: The code at line 544 was first introduced by commit
:::::: b26975593b17c2c7188b96dba6fe9fff14480538 display/drm/bridge: TC358775 DSI/LVDS driver

:::::: TO: Vinay Simha BN <simhavcs@xxxxxxxxx>
:::::: CC: Sam Ravnborg <sam.ravnborg@xxxxxxxxx>

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