OMAPDSS: use DISPC register to detect context loss

Instead of relying on the OMAP specific
omap_pm_get_dev_context_loss_count() to detect register context loss, we
can achieve the same in a much simpler way by just observing the DISPC
registers.

We always set DISPC's load mode to LOAD_FRAME_ONLY, which is not the
reset value. Thus we can just observe the load mode to see if we have
lost register context.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Archit Taneja <archit@ti.com>

1 files changed, 11 insertions, 13 deletions

diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index bbeb8dd7f108..1659aa912d2b 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -100,8 +100,6 @@ static struct {
         struct platform_device *pdev;
         void __iomem    *base;
 
-        int             ctx_loss_cnt;
-
         int irq;
 
         unsigned long core_clk_rate;
@@ -357,29 +355,20 @@ static void dispc_save_context(void)
         if (dss_has_feature(FEAT_CORE_CLK_DIV))
                 SR(DIVISOR);
 
-        dispc.ctx_loss_cnt = dss_get_ctx_loss_count();
         dispc.ctx_valid = true;
 
-        DSSDBG("context saved, ctx_loss_count %d\n", dispc.ctx_loss_cnt);
+        DSSDBG("context saved\n");
 }
 
 static void dispc_restore_context(void)
 {
-        int i, j, ctx;
+        int i, j;
 
         DSSDBG("dispc_restore_context\n");
 
         if (!dispc.ctx_valid)
                 return;
 
-        ctx = dss_get_ctx_loss_count();
-
-        if (ctx >= 0 && ctx == dispc.ctx_loss_cnt)
-                return;
-
-        DSSDBG("ctx_loss_count: saved %d, current %d\n",
-                        dispc.ctx_loss_cnt, ctx);
-
         /*RR(IRQENABLE);*/
         /*RR(CONTROL);*/
         RR(CONFIG);
@@ -3768,6 +3757,15 @@ static int dispc_runtime_suspend(struct device *dev)
 
 static int dispc_runtime_resume(struct device *dev)
 {
+        /*
+         * The reset value for load mode is 0 (OMAP_DSS_LOAD_CLUT_AND_FRAME)
+         * but we always initialize it to 2 (OMAP_DSS_LOAD_FRAME_ONLY) in
+         * _omap_dispc_initial_config(). We can thus use it to detect if
+         * we have lost register context.
+         */
+        if (REG_GET(DISPC_CONFIG, 2, 1) == OMAP_DSS_LOAD_FRAME_ONLY)
+                return 0;
+
         _omap_dispc_initial_config();
 
         dispc_restore_context();