From: Archit Taneja <architt@codeaurora.org>
Date: Mon, 12 Feb 2018 12:01:07 +0530
Subject: drm/msm/dsi: Get byte_intf_clk only for versions that need it
Git-commit: fb48989edb628342af0fad478174ae30b2e1e23a
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Newer DSI host controllers (SDM845 in particular) require a new clock
called byte_intf_clk. A recent patch tried to add this as an optional
clock, but it still set 'ret' to an error number if it didn't find it.
This breaks the host's probe for all previous DSI host versions.

Instead of setting this up as an optional clock, try to get the clock
only for the DSI version that supports it.

Fixes: 56558fb ("drm/msm/dsi: Add byte_intf_clk")
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -378,11 +378,16 @@ static int dsi_clk_init(struct msm_dsi_h
 		goto exit;
 	}
 
-	msm_host->byte_intf_clk = msm_clk_get(pdev, "byte_intf");
-	if (IS_ERR(msm_host->byte_intf_clk)) {
-		ret = PTR_ERR(msm_host->byte_intf_clk);
-		pr_debug("%s: can't find byte_intf clock. ret=%d\n",
-			 __func__, ret);
+	if (cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
+	    cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V2_2_1) {
+		msm_host->byte_intf_clk = msm_clk_get(pdev, "byte_intf");
+		if (IS_ERR(msm_host->byte_intf_clk)) {
+			ret = PTR_ERR(msm_host->byte_intf_clk);
+			pr_err("%s: can't find byte_intf clock. ret=%d\n",
+			        __func__, ret);
+			goto exit;
+		}
+	} else {
 		msm_host->byte_intf_clk = NULL;
 	}