This is a note to let you know that I've just added the patch titled
drm: fsl-dcu: enable PIXCLK on LS1021A
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-fsl-dcu-enable-pixclk-on-ls1021a.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 92c4cab6e83854d423dd7ddcb918d83ff622fb56
Author: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxx>
Date: Thu Sep 26 07:55:51 2024 +0200
drm: fsl-dcu: enable PIXCLK on LS1021A
[ Upstream commit ffcde9e44d3e18fde3d18bfff8d9318935413bfd ]
The PIXCLK needs to be enabled in SCFG before accessing certain DCU
registers, or the access will hang. For simplicity, the PIXCLK is enabled
unconditionally, resulting in increased power consumption.
Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxx>
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
Fixes: 109eee2f2a18 ("drm/layerscape: Add Freescale DCU DRM driver")
Acked-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240926055552.1632448-2-alexander.stein@xxxxxxxxxxxxxxx
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/fsl-dcu/Kconfig b/drivers/gpu/drm/fsl-dcu/Kconfig
index d7dd8ba90e3af..9e5a35e7c00cc 100644
--- a/drivers/gpu/drm/fsl-dcu/Kconfig
+++ b/drivers/gpu/drm/fsl-dcu/Kconfig
@@ -8,6 +8,7 @@ config DRM_FSL_DCU
select DRM_PANEL
select REGMAP_MMIO
select VIDEOMODE_HELPERS
+ select MFD_SYSCON if SOC_LS1021A
help
Choose this option if you have an Freescale DCU chipset.
If M is selected the module will be called fsl-dcu-drm.
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 660fe573db969..ab1d718fda5b5 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -100,6 +100,7 @@ static void fsl_dcu_irq_uninstall(struct drm_device *dev)
static int fsl_dcu_load(struct drm_device *dev, unsigned long flags)
{
struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
+ struct regmap *scfg;
int ret;
ret = fsl_dcu_drm_modeset_init(fsl_dev);
@@ -108,6 +109,20 @@ static int fsl_dcu_load(struct drm_device *dev, unsigned long flags)
return ret;
}
+ scfg = syscon_regmap_lookup_by_compatible("fsl,ls1021a-scfg");
+ if (PTR_ERR(scfg) != -ENODEV) {
+ /*
+ * For simplicity, enable the PIXCLK unconditionally,
+ * resulting in increased power consumption. Disabling
+ * the clock in PM or on unload could be implemented as
+ * a future improvement.
+ */
+ ret = regmap_update_bits(scfg, SCFG_PIXCLKCR, SCFG_PIXCLKCR_PXCEN,
+ SCFG_PIXCLKCR_PXCEN);
+ if (ret < 0)
+ return dev_err_probe(dev->dev, ret, "failed to enable pixclk\n");
+ }
+
ret = drm_vblank_init(dev, dev->mode_config.num_crtc);
if (ret < 0) {
dev_err(dev->dev, "failed to initialize vblank\n");
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
index e2049a0e8a92a..566396013c04a 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
@@ -160,6 +160,9 @@
#define FSL_DCU_ARGB4444 12
#define FSL_DCU_YUV422 14
+#define SCFG_PIXCLKCR 0x28
+#define SCFG_PIXCLKCR_PXCEN BIT(31)
+
#define VF610_LAYER_REG_NUM 9
#define LS1021A_LAYER_REG_NUM 10
