From: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxx>
The PIXCLK needs to be enabled in SCFG before accessing certain DCU
registers, or the access will hang.
Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxx>
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/fsl-dcu/Kconfig | 1 +
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 14 ++++++++++++++
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h | 3 +++
3 files changed, 18 insertions(+)
diff --git a/drivers/gpu/drm/fsl-dcu/Kconfig b/drivers/gpu/drm/fsl-dcu/Kconfig
index 5ca71ef87325..c9ee98693b48 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 418887654bac..314cb8af89ee 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -100,12 +100,26 @@ 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);
if (ret < 0)
return dev_err_probe(dev->dev, ret, "failed to initialize mode setting\n");
+ scfg = syscon_regmap_lookup_by_compatible("fsl,ls1021a-scfg");
+ if (PTR_ERR(scfg) != -ENODEV) {
+ /*
+ * For simplicity, enable the PIXCLK unconditionally. 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 e2049a0e8a92..566396013c04 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
--
2.34.1
