[PATCH 3/5] drm/msm/mdss: check for core clk before accessing HW_REV

[Dmitry Baryshkov]

Rather than checking whether the platform is an mdp5 or dpu platform,
check if the MDP_CLK is provided or not before trying to access HW_REV
(and skip reading the registers if the clock is not provided by the DT).

Signed-off-by: Dmitry Baryshkov <dmitry.barysh...@linaro.org>
---
 drivers/gpu/drm/msm/msm_mdss.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_mdss.c b/drivers/gpu/drm/msm/msm_mdss.c
index f7b4628986b8..d81d8fe3584e 100644
--- a/drivers/gpu/drm/msm/msm_mdss.c
+++ b/drivers/gpu/drm/msm/msm_mdss.c
@@ -32,7 +32,6 @@ struct msm_mdss {
        void __iomem *mmio;
        struct clk_bulk_data *clocks;
        size_t num_clocks;
-       bool is_mdp5;
        struct {
                unsigned long enabled_mask;
                struct irq_domain *domain;
@@ -186,6 +185,19 @@ static void msm_mdss_setup_ubwc_dec_40(struct msm_mdss 
*msm_mdss,
        }
 }
 
+static bool msm_mdss_has_clock(struct msm_mdss *msm_mdss, const char *name)
+{
+       unsigned int i;
+
+       for (i = 0; i < msm_mdss->num_clocks; i++) {
+               if (!strcmp(msm_mdss->clocks[i].id, name) &&
+                   msm_mdss->clocks[i].clk)
+                       return true;
+       }
+
+       return false;
+}
+
 static int msm_mdss_enable(struct msm_mdss *msm_mdss)
 {
        int ret;
@@ -198,10 +210,11 @@ static int msm_mdss_enable(struct msm_mdss *msm_mdss)
        }
 
        /*
-        * HW_REV requires MDSS_MDP_CLK, which is not enabled by the mdss on
-        * mdp5 hardware. Skip reading it for now.
+        * HW_REV requires MDSS_MDP_CLK, which is not used for MDSS device in
+        * older device trees. Skip accessing registers if the clock is not
+        * present.
         */
-       if (msm_mdss->is_mdp5)
+       if (!msm_mdss_has_clock(msm_mdss, "core"))
                return 0;
 
        hw_rev = readl_relaxed(msm_mdss->mmio + HW_REV);
@@ -345,7 +358,6 @@ static struct msm_mdss *msm_mdss_init(struct 
platform_device *pdev, bool is_mdp5
                return ERR_PTR(ret);
        }
        msm_mdss->num_clocks = ret;
-       msm_mdss->is_mdp5 = is_mdp5;
 
        msm_mdss->dev = &pdev->dev;
 
-- 
2.35.1