The PIXCLK needs to be enabled in SCFG before accessing the DCU on LS1021A,
or the access will hang.
Signed-off-by: Matthias Schiffer <matthias.schif...@ew.tq-group.com>
---
drivers/gpu/drm/fsl-dcu/Kconfig | 1 +
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 25 +++++++++++++++++++++++
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h | 3 +++
3 files changed, 29 insertions(+)
diff --git a/drivers/gpu/drm/fsl-dcu/Kconfig b/drivers/gpu/drm/fsl-dcu/Kconfig
index d7dd8ba90e3a..9e5a35e7c00c 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 abbc1ddbf27f..8a7556655581 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -51,6 +51,23 @@ static const struct regmap_config fsl_dcu_regmap_config = {
.volatile_reg = fsl_dcu_drm_is_volatile_reg,
};
+static int fsl_dcu_scfg_config_ls1021a(struct device_node *np)
+{
+ struct regmap *scfg;
+
+ scfg = syscon_regmap_lookup_by_compatible("fsl,ls1021a-scfg");
+ if (IS_ERR(scfg))
+ return PTR_ERR(scfg);
+
+ /*
+ * For simplicity, enable the PIXCLK unconditionally. It might
+ * be possible to disable the clock in PM or on unload as a future
+ * improvement.
+ */
+ return regmap_update_bits(scfg, SCFG_PIXCLKCR, SCFG_PIXCLKCR_PXCEN,
+ SCFG_PIXCLKCR_PXCEN);
+}
+
static void fsl_dcu_irq_uninstall(struct drm_device *dev)
{
struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
@@ -70,6 +87,14 @@ static int fsl_dcu_load(struct drm_device *dev, unsigned
long flags)
return ret;
}
+ if (of_device_is_compatible(fsl_dev->np, "fsl,ls1021a-dcu")) {
+ ret = fsl_dcu_scfg_config_ls1021a(fsl_dev->np);
+ if (ret < 0) {
+ dev_err(dev->dev, "failed to enable pixclk\n");
+ goto done;
+ }
+ }
+
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
--
2.17.1
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