drm/i915/psr: clean up PSR debugfs sink status error handling

Handle errors first and return early, and reduce indentation on the
happy day code path.

Cc: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230317134144.223936-3-jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index bd1a1a2..31084d9 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -2891,6 +2891,7 @@ static int i915_psr_sink_status_show(struct seq_file *m, void *data)
                "reserved",
                "sink internal error",
        };
+       const char *str;
        int ret;
        u8 val;
 
@@ -2903,17 +2904,16 @@ static int i915_psr_sink_status_show(struct seq_file *m, void *data)
                return -ENODEV;
 
        ret = drm_dp_dpcd_readb(&intel_dp->aux, DP_PSR_STATUS, &val);
+       if (ret != 1)
+               return ret < 0 ? ret : -EIO;
 
-       if (ret == 1) {
-               const char *str = "unknown";
+       val &= DP_PSR_SINK_STATE_MASK;
+       if (val < ARRAY_SIZE(sink_status))
+               str = sink_status[val];
+       else
+               str = "unknown";
 
-               val &= DP_PSR_SINK_STATE_MASK;
-               if (val < ARRAY_SIZE(sink_status))
-                       str = sink_status[val];
-               seq_printf(m, "Sink PSR status: 0x%x [%s]\n", val, str);
-       } else {
-               return ret;
-       }
+       seq_printf(m, "Sink PSR status: 0x%x [%s]\n", val, str);
 
        return 0;
 }