Re: [PATCH v5 5/7] drm/verisilicon: add DC8000 (DCUltraLite) display controller support

[Joey Lu <a0987203069@gmail.com>]

On 6/26/2026 4:03 PM, Icenowy Zheng wrote:
> 在 2026-06-25四的 17:44 +0800，Joey Lu写道：
>> The Nuvoton MA35D1 SoC integrates a Verisilicon DCUltraLite display
>> controller (DC8000 generation) whose register layout differs from
>> the DC8200 in several important ways:
>>
>> 1. No CONFIG_EX commit path: framebuffer updates use the enable (bit
>> 0)
>>     and reset (bit 4) bits in FB_CONFIG instead of the DC8200 staging
>>     registers (FB_CONFIG_EX, FB_TOP_LEFT, FB_BOTTOM_RIGHT,
>>     FB_BLEND_CONFIG, PANEL_CONFIG_EX).
>>
>> 2. No PANEL_START register: panel output starts when
>>     PANEL_CONFIG.RUNNING is set; there is no multi-display sync start
>>     register.
>>
>> 3. Different IRQ registers: DCUltraLite uses DISP_IRQ_STA (0x147C) /
>>     DISP_IRQ_EN (0x1480) versus DC8200's TOP_IRQ_ACK (0x0010) /
>>     TOP_IRQ_EN (0x0014).
>>
>> 4. Simpler clock topology: only 'core' (bus gate) and 'pix0' (pixel
>>     divider) clocks; no axi or ahb clocks required.
>>
>> Signed-off-by: Joey Lu <a0987203069@gmail.com>
>> ---
>>   drivers/gpu/drm/verisilicon/Makefile    |  2 +-
>>   drivers/gpu/drm/verisilicon/vs_dc.c     |  5 +-
>>   drivers/gpu/drm/verisilicon/vs_dc.h     |  1 +
>>   drivers/gpu/drm/verisilicon/vs_dc8000.c | 86
>> +++++++++++++++++++++++++
>>   4 files changed, 92 insertions(+), 2 deletions(-)
>>   create mode 100644 drivers/gpu/drm/verisilicon/vs_dc8000.c
>>
>> diff --git a/drivers/gpu/drm/verisilicon/Makefile
>> b/drivers/gpu/drm/verisilicon/Makefile
>> index 9d4cd16452fa..d2fd8e4dff24 100644
>> --- a/drivers/gpu/drm/verisilicon/Makefile
>> +++ b/drivers/gpu/drm/verisilicon/Makefile
>> @@ -1,6 +1,6 @@
>>   # SPDX-License-Identifier: GPL-2.0-only
>>   
>> -verisilicon-dc-objs := vs_bridge.o vs_crtc.o vs_dc.o vs_dc8200.o
>> vs_drm.o vs_hwdb.o \
>> +verisilicon-dc-objs := vs_bridge.o vs_crtc.o vs_dc.o vs_dc8200.o
>> vs_dc8000.o vs_drm.o vs_hwdb.o \
>>   	vs_plane.o vs_primary_plane.o vs_cursor_plane.o
>>   
>>   obj-$(CONFIG_DRM_VERISILICON_DC) += verisilicon-dc.o
>> diff --git a/drivers/gpu/drm/verisilicon/vs_dc.c
>> b/drivers/gpu/drm/verisilicon/vs_dc.c
>> index fd1f5fe67a68..9499fffbca58 100644
>> --- a/drivers/gpu/drm/verisilicon/vs_dc.c
>> +++ b/drivers/gpu/drm/verisilicon/vs_dc.c
>> @@ -134,7 +134,10 @@ static int vs_dc_probe(struct platform_device
>> *pdev)
>>   	dev_info(dev, "Found DC%x rev %x customer %x\n", dc-
>>> identity.model,
>>   		 dc->identity.revision, dc->identity.customer_id);
>>   
>> -	dc->funcs = &vs_dc8200_funcs;
>> +	if (dc->identity.generation == VSDC_GEN_DC8200)
>> +		dc->funcs = &vs_dc8200_funcs;
>> +	else
>> +		dc->funcs = &vs_dc8000_funcs;
>>   
>>   	if (port_count > dc->identity.display_count) {
>>   		dev_err(dev, "too many downstream ports than HW
>> capability\n");
>> diff --git a/drivers/gpu/drm/verisilicon/vs_dc.h
>> b/drivers/gpu/drm/verisilicon/vs_dc.h
>> index 825f5dd6bf17..ac96ad701199 100644
>> --- a/drivers/gpu/drm/verisilicon/vs_dc.h
>> +++ b/drivers/gpu/drm/verisilicon/vs_dc.h
>> @@ -66,5 +66,6 @@ struct vs_dc {
>>   };
>>   
>>   extern const struct vs_dc_funcs vs_dc8200_funcs;
>> +extern const struct vs_dc_funcs vs_dc8000_funcs;
>>   
>>   #endif /* _VS_DC_H_ */
>> diff --git a/drivers/gpu/drm/verisilicon/vs_dc8000.c
>> b/drivers/gpu/drm/verisilicon/vs_dc8000.c
>> new file mode 100644
>> index 000000000000..fbe0fa516cac
>> --- /dev/null
>> +++ b/drivers/gpu/drm/verisilicon/vs_dc8000.c
>> @@ -0,0 +1,86 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2026 Joey Lu <yclu4@nuvoton.com>
>> + */
>> +
>> +#include <linux/regmap.h>
>> +
>> +#include "vs_crtc_regs.h"
>> +#include "vs_dc.h"
>> +#include "vs_drm.h"
>> +#include "vs_primary_plane_regs.h"
>> +
>> +static void vs_dc8000_panel_enable_ex(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_set_bits(dc->regs, VSDC_FB_CONFIG(output),
>> +			VSDC_FB_CONFIG_RESET);
>> +}
>> +
>> +static void vs_dc8000_panel_disable_ex(struct vs_dc *dc, unsigned
>> int output)
>> +{
>> +	regmap_clear_bits(dc->regs, VSDC_FB_CONFIG(output),
>> +			  VSDC_FB_CONFIG_RESET);
>> +}
>> +
>> +static void vs_dc8000_crtc_begin(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_set_bits(dc->regs, VSDC_FB_CONFIG(output),
>> +			VSDC_FB_CONFIG_VALID);
>> +}
>> +
>> +static void vs_dc8000_crtc_flush(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_clear_bits(dc->regs, VSDC_FB_CONFIG(output),
>> +			  VSDC_FB_CONFIG_VALID);
>> +}
>> +
>> +static void vs_dc8000_crtc_enable_ex(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_set_bits(dc->regs, VSDC_FB_CONFIG(output),
>> +			VSDC_FB_CONFIG_ENABLE);
>> +}
>> +
>> +static void vs_dc8000_crtc_disable_ex(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_clear_bits(dc->regs, VSDC_FB_CONFIG(output),
>> +			  VSDC_FB_CONFIG_ENABLE);
>> +}
>> +
>> +static void vs_dc8000_enable_vblank(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_set_bits(dc->regs, VSDC_DISP_IRQ_EN,
>> +			VSDC_DISP_IRQ_VSYNC(output));
>> +}
>> +
>> +static void vs_dc8000_disable_vblank(struct vs_dc *dc, unsigned int
>> output)
>> +{
>> +	regmap_clear_bits(dc->regs, VSDC_DISP_IRQ_EN,
>> +			  VSDC_DISP_IRQ_VSYNC(output));
>> +}
>> +
>> +static u32 vs_dc8000_irq_ack(struct vs_dc *dc)
>> +{
>> +	u32 hw_irqs, unified = 0;
>> +	unsigned int i;
>> +
>> +	regmap_read(dc->regs, VSDC_DISP_IRQ_STA, &hw_irqs);
>> +
>> +	for (i = 0; i < VSDC_MAX_OUTPUTS; i++) {
>> +		if (hw_irqs & VSDC_DISP_IRQ_VSYNC(i))
>> +			unified |= VSDC_IRQ_VSYNC(i);
>> +	}
> Maybe a warning for unknown IRQ bits should be added here.
>
> Thanks,
> Icenowy
I will add the same `drm_WARN_ONCE` pattern in `vs_dc8000_irq_ack` for
unknown `VSDC_DISP_IRQ_STA` bits.
>> +
>> +	return unified;
>> +}
>> +
>> +const struct vs_dc_funcs vs_dc8000_funcs = {
>> +	.panel_enable_ex	= vs_dc8000_panel_enable_ex,
>> +	.panel_disable_ex	= vs_dc8000_panel_disable_ex,
>> +	.crtc_begin		= vs_dc8000_crtc_begin,
>> +	.crtc_flush		= vs_dc8000_crtc_flush,
>> +	.crtc_enable_ex		= vs_dc8000_crtc_enable_ex,
>> +	.crtc_disable_ex	= vs_dc8000_crtc_disable_ex,
>> +	.enable_vblank		= vs_dc8000_enable_vblank,
>> +	.disable_vblank		= vs_dc8000_disable_vblank,
>> +	.irq_ack		= vs_dc8000_irq_ack,
>> +};