On 20/01/2023 18:16, Laurent Pinchart wrote:
Hi Tomi,
Thank you for the patch.
On Fri, Jan 20, 2023 at 10:50:04AM +0200, Tomi Valkeinen wrote:
Add simple runtime PM suspend and resume functionality.
I think you need to depend on PM in Kconfig. That's not a compile-time
dependency but a runtime-dependency, with runtime PM support the
suspend/resume handler will never be called.
Yes, LVDS won't work without runtime PM after this patch.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/rcar-du/rcar_lvds.c | 43 +++++++++++++++++++++++++----
1 file changed, 37 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index 81a060c2fe3f..8e1be51fbee6 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -16,6 +16,7 @@
#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/sys_soc.h>
@@ -316,8 +317,8 @@ int rcar_lvds_pclk_enable(struct drm_bridge *bridge, unsigned long freq)
dev_dbg(lvds->dev, "enabling LVDS PLL, freq=%luHz\n", freq);
- ret = clk_prepare_enable(lvds->clocks.mod);
- if (ret < 0)
+ ret = pm_runtime_resume_and_get(lvds->dev);
+ if (ret)
return ret;
__rcar_lvds_pll_setup_d3_e3(lvds, freq, true);
@@ -337,7 +338,7 @@ void rcar_lvds_pclk_disable(struct drm_bridge *bridge)
rcar_lvds_write(lvds, LVDPLLCR, 0);
- clk_disable_unprepare(lvds->clocks.mod);
+ pm_runtime_put(lvds->dev);
Should we use pm_runtime_put_sync() here, to make sure the clock gets
disabled right away ? The DU hardware may depend on the exact sequencing
of events. I would then do the same in rcar_lvds_atomic_disable().
That's perhaps a good idea. I think I saw some of the docs saying that
startup sequences must begin with the reset. If we don't use _sync, we
could end up not resetting at all.
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Thanks!
Tomi
