[PATCH v3 10/12] drm/i915: Read DP branch device HW revision

[Mika Kahola]

HW revision is mandatory field for DisplayPort branch
devices. This is defined in DPCD register field 0x509.

Signed-off-by: Mika Kahola <mika.kahola at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 5 +++++
 include/drm/drm_dp_helper.h     | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 2b768da..12ab26b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3463,6 +3463,11 @@ intel_dp_probe_oui(struct intel_dp *intel_dp)
                if (drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_ID, 
intel_dp->bd.id,
                                     sizeof(intel_dp->bd.id)) == 
sizeof(intel_dp->bd.id))
                        DRM_DEBUG_KMS("Device ID: %s\n", intel_dp->bd.id);
+
+               if (drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_HW_REV, 
&intel_dp->bd.hw_rev,
+                                    sizeof(intel_dp->bd.hw_rev)) == 
sizeof(intel_dp->bd.hw_rev))
+                       DRM_DEBUG_KMS("HW revision: %.2d.%.2d\n",
+                                     intel_dp->bd.hw_rev & 0xf, 
(intel_dp->bd.hw_rev>>4) & 0xf);
        }
 }

diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index f1fc4e2..d0965ca 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -458,6 +458,7 @@
 #define DP_SINK_OUI                        0x400
 #define DP_BRANCH_OUI                      0x500
 #define DP_BRANCH_ID                        0x503
+#define DP_BRANCH_HW_REV                    0x509

 #define DP_SET_POWER                        0x600
 # define DP_SET_POWER_D0                    0x1
@@ -871,6 +872,7 @@ struct drm_dp_bd {
        int type;
        bool hpd;
        uint8_t id[6];
+       uint8_t hw_rev;
        union {
                struct drm_dp_vga vga;
                struct drm_dp_dvi dvi;
-- 
1.9.1