From c4cba44eeecab9d5ccd3dd2d5520a7d1e5be544f Mon Sep 17 00:00:00 2001 From: Jonas Karlman Date: Sun, 21 Apr 2019 08:25:50 +0000 Subject: [PATCH] drm/bridge: dw-hdmi: fix SCDC configuration for ddc-i2c-bus When ddc-i2c-bus property is used, a NULL pointer dereference is reported: [ 31.041669] Unable to handle kernel NULL pointer dereference at virtual address 00000008 [ 31.041671] pgd = 4d3c16f6 [ 31.041673] [00000008] *pgd=00000000 [ 31.041678] Internal error: Oops: 5 [#1] SMP ARM [ 31.041711] Hardware name: Rockchip (Device Tree) [ 31.041718] PC is at i2c_transfer+0x8/0xe4 [ 31.041721] LR is at drm_scdc_read+0x54/0x84 [ 31.041723] pc : [] lr : [] psr: 280f0013 [ 31.041725] sp : edffdad0 ip : 5ccb5511 fp : 00000058 [ 31.041727] r10: 00000780 r9 : edf91608 r8 : c11b0f48 [ 31.041728] r7 : 00000438 r6 : 00000000 r5 : 00000000 r4 : 00000000 [ 31.041730] r3 : edffdae7 r2 : 00000002 r1 : edffdaec r0 : 00000000 [ 31.041908] [] (i2c_transfer) from [] (drm_scdc_read+0x54/0x84) [ 31.041913] [] (drm_scdc_read) from [] (drm_scdc_set_scrambling+0x30/0xbc) [ 31.041919] [] (drm_scdc_set_scrambling) from [] (dw_hdmi_update_power+0x1440/0x1610) [ 31.041926] [] (dw_hdmi_update_power) from [] (dw_hdmi_bridge_enable+0x2c/0x70) [ 31.041932] [] (dw_hdmi_bridge_enable) from [] (drm_bridge_enable+0x24/0x34) [ 31.041938] [] (drm_bridge_enable) from [] (drm_atomic_helper_commit_modeset_enables+0x114/0x220) [ 31.041943] [] (drm_atomic_helper_commit_modeset_enables) from [] (rockchip_atomic_helper_commit_tail_rpm+0x28/0x64) hdmi->i2c may not be set when ddc-i2c-bus property is used in device tree. Fix this by using hdmi->ddc as the i2c adapter when calling drm_scdc_*(). Also report that SCDC is not supported when there is no DDC bus. Fixes: 264fce6cc2c1 ("drm/bridge: dw-hdmi: Add SCDC and TMDS Scrambling support") Signed-off-by: Jonas Karlman Reviewed-by: Heiko Stuebner Reviewed-by: Neil Armstrong Reviewed-by: Laurent Pinchart Signed-off-by: Andrzej Hajda Link: https://patchwork.freedesktop.org/patch/msgid/VE1PR03MB59031814B5BCAB2152923BDAAC210@VE1PR03MB5903.eurprd03.prod.outlook.com --- drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index b74ccb6a24c2..ab7968c8f6a2 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c @@ -1046,6 +1046,10 @@ static bool dw_hdmi_support_scdc(struct dw_hdmi *hdmi) if (hdmi->version < 0x200a) return false; + /* Disable if no DDC bus */ + if (!hdmi->ddc) + return false; + /* Disable if SCDC is not supported, or if an HF-VSDB block is absent */ if (!display->hdmi.scdc.supported || !display->hdmi.scdc.scrambling.supported) @@ -1684,13 +1688,13 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi, * Source Devices compliant shall set the * Source Version = 1. */ - drm_scdc_readb(&hdmi->i2c->adap, SCDC_SINK_VERSION, + drm_scdc_readb(hdmi->ddc, SCDC_SINK_VERSION, &bytes); - drm_scdc_writeb(&hdmi->i2c->adap, SCDC_SOURCE_VERSION, + drm_scdc_writeb(hdmi->ddc, SCDC_SOURCE_VERSION, min_t(u8, bytes, SCDC_MIN_SOURCE_VERSION)); /* Enabled Scrambling in the Sink */ - drm_scdc_set_scrambling(&hdmi->i2c->adap, 1); + drm_scdc_set_scrambling(hdmi->ddc, 1); /* * To activate the scrambler feature, you must ensure @@ -1706,7 +1710,7 @@ static void hdmi_av_composer(struct dw_hdmi *hdmi, hdmi_writeb(hdmi, 0, HDMI_FC_SCRAMBLER_CTRL); hdmi_writeb(hdmi, (u8)~HDMI_MC_SWRSTZ_TMDSSWRST_REQ, HDMI_MC_SWRSTZ); - drm_scdc_set_scrambling(&hdmi->i2c->adap, 0); + drm_scdc_set_scrambling(hdmi->ddc, 0); } } -- 2.45.2