[PATCH 08/10] drm/tidss: Add dispc_is_idle()

[Tomi Valkeinen]

Add a helper function, dispc_is_idle(), which returns whether the DSS is
idle (i.e. is any video port enabled).

For now we add a call to it in the suspend and resume callbacks, and
print a warning if in either place the DSS is not idle. In the future
this can be used to detect if the bootloader had enabled the DSS, and
the driver can act on that.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
---
 drivers/gpu/drm/tidss/tidss_dispc.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index 13db062892e3..a527c28c8833 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -2603,10 +2603,18 @@ void dispc_vp_setup(struct dispc_device *dispc, u32 hw_videoport,
 	dispc_vp_set_color_mgmt(dispc, hw_videoport, state, newmodeset);
 }
 
+static bool dispc_is_idle(struct dispc_device *dispc)
+{
+	return REG_GET(dispc, DSS_SYSSTATUS, 9, 9);
+}
+
 int dispc_runtime_suspend(struct dispc_device *dispc)
 {
 	dev_dbg(dispc->dev, "suspend\n");
 
+	if (!dispc_is_idle(dispc))
+		dev_warn(dispc->dev, "Bad HW state: DSS not idle when suspending");
+
 	dispc->is_enabled = false;
 
 	clk_disable_unprepare(dispc->fclk);
@@ -2620,6 +2628,9 @@ int dispc_runtime_resume(struct dispc_device *dispc)
 
 	clk_prepare_enable(dispc->fclk);
 
+	if (!dispc_is_idle(dispc))
+		dev_warn(dispc->dev, "Bad HW state: DSS not idle when resuming");
+
 	if (REG_GET(dispc, DSS_SYSSTATUS, 0, 0) == 0)
 		dev_warn(dispc->dev, "DSS FUNC RESET not done!\n");
 

-- 
2.34.1