drm/i915/dp: use readb and writeb calls for single byte DPCD access

This is what we have the readb and writeb variants for. Do some minor
return value and variable cleanup while at it.

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/fd8a8f110bcfdc73a8c9241e5f9d61f7dd7c9677.1491485983.git.jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 6f743490855ba16a9f85c21ff3a9c876a12cd320..81682fd2804b393180871be9138e5ac1eb00f5e2 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3661,9 +3661,9 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
                uint8_t frame_sync_cap;
 
                dev_priv->psr.sink_support = true;
-               drm_dp_dpcd_read(&intel_dp->aux,
-                                DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
-                                &frame_sync_cap, 1);
+               drm_dp_dpcd_readb(&intel_dp->aux,
+                                 DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
+                                 &frame_sync_cap);
                dev_priv->psr.aux_frame_sync = frame_sync_cap ? true : false;
                /* PSR2 needs frame sync as well */
                dev_priv->psr.psr2_support = dev_priv->psr.aux_frame_sync;
@@ -3737,8 +3737,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
                intel_dp_set_common_rates(intel_dp);
        }
 
-       if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
-                            &intel_dp->sink_count, 1) < 0)
+       if (drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT,
+                             &intel_dp->sink_count) <= 0)
                return false;
 
        /*
@@ -3775,7 +3775,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 static bool
 intel_dp_can_mst(struct intel_dp *intel_dp)
 {
-       u8 buf[1];
+       u8 mstm_cap;
 
        if (!i915.enable_dp_mst)
                return false;
@@ -3786,10 +3786,10 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
        if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
                return false;
 
-       if (drm_dp_dpcd_read(&intel_dp->aux, DP_MSTM_CAP, buf, 1) != 1)
+       if (drm_dp_dpcd_readb(&intel_dp->aux, DP_MSTM_CAP, &mstm_cap) != 1)
                return false;
 
-       return buf[0] & DP_MST_CAP;
+       return mstm_cap & DP_MST_CAP;
 }
 
 static void
@@ -3935,9 +3935,8 @@ stop:
 static bool
 intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 {
-       return drm_dp_dpcd_read(&intel_dp->aux,
-                                      DP_DEVICE_SERVICE_IRQ_VECTOR,
-                                      sink_irq_vector, 1) == 1;
+       return drm_dp_dpcd_readb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+                                sink_irq_vector) == 1;
 }
 
 static bool
@@ -4000,13 +3999,13 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
 {
        uint8_t test_pattern;
-       uint16_t test_misc;
+       uint8_t test_misc;
        __be16 h_width, v_height;
        int status = 0;
 
        /* Read the TEST_PATTERN (DP CTS 3.1.5) */
-       status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_PATTERN,
-                                 &test_pattern, 1);
+       status = drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_PATTERN,
+                                  &test_pattern);
        if (status <= 0) {
                DRM_DEBUG_KMS("Test pattern read failed\n");
                return DP_TEST_NAK;
@@ -4028,8 +4027,8 @@ static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
                return DP_TEST_NAK;
        }
 
-       status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_MISC0,
-                                 &test_misc, 1);
+       status = drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_MISC0,
+                                  &test_misc);
        if (status <= 0) {
                DRM_DEBUG_KMS("TEST MISC read failed\n");
                return DP_TEST_NAK;
@@ -4088,10 +4087,8 @@ static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
                 */
                block += intel_connector->detect_edid->extensions;
 
-               if (!drm_dp_dpcd_write(&intel_dp->aux,
-                                       DP_TEST_EDID_CHECKSUM,
-                                       &block->checksum,
-                                       1))
+               if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_EDID_CHECKSUM,
+                                      block->checksum) <= 0)
                        DRM_DEBUG_KMS("Failed to write EDID checksum\n");
 
                test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;