From ffcde9e44d3e18fde3d18bfff8d9318935413bfd Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <matthias.schiffer@tq-group.com>
Date: Thu, 26 Sep 2024 07:55:51 +0200
Subject: [PATCH] drm: fsl-dcu: enable PIXCLK on LS1021A
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@tq-group.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Fixes: 109eee2f2a18 ("drm/layerscape: Add Freescale DCU DRM driver")
Acked-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240926055552.1632448-2-alexander.stein@ew.tq-group.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
drivers/gpu/drm/fsl-dcu/Kconfig | 1 +
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 15 +++++++++++++++
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h | 3 +++
3 files changed, 19 insertions(+)
diff --git a/drivers/gpu/drm/fsl-dcu/Kconfig b/drivers/gpu/drm/fsl-dcu/Kconfig
index 588ce2420af26..0e0f910ceb9f0 100644
--- a/drivers/gpu/drm/fsl-dcu/Kconfig
+++ b/drivers/gpu/drm/fsl-dcu/Kconfig
@@ -9,6 +9,7 @@ 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 e62f581282831..6886487adc94c 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -101,12 +101,27 @@ 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,
+ * 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
--
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