1. Patchew
  2. linux
  3. [PATCH v2 00/15] drm: sprd: Make the Unisoc DRM driver usable on UMS9230
  4. View patch

[PATCH v2 10/15] drm: sprd: add clock gating support

Otto Pflüger posted 15 patches 2 months, 2 weeks ago
There is a newer version of this series
[PATCH v2 10/15] drm: sprd: add clock gating support
Posted by Otto Pflüger 2 months, 2 weeks ago 
Enable the DPU and DSI clocks specified in the device tree.
Disable the DSI clock when it is not needed.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
---
 drivers/gpu/drm/sprd/sprd_dpu.c | 7 +++++++
 drivers/gpu/drm/sprd/sprd_dpu.h | 1 +
 drivers/gpu/drm/sprd/sprd_dsi.c | 9 +++++++++
 drivers/gpu/drm/sprd/sprd_dsi.h | 4 +++-
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/sprd/sprd_dpu.c b/drivers/gpu/drm/sprd/sprd_dpu.c
index 0d9eb778794d92418b39f8535d94abde3566de43..9d274600e6a80bdfc435f6c6eff77c9dd71cb38c 100644
--- a/drivers/gpu/drm/sprd/sprd_dpu.c
+++ b/drivers/gpu/drm/sprd/sprd_dpu.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2020 Unisoc Inc.
  */
 
+#include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/delay.h>
 #include <linux/dma-buf.h>
@@ -794,6 +795,12 @@ static int sprd_dpu_context_init(struct sprd_dpu *dpu,
 	if (ctx->irq < 0)
 		return ctx->irq;
 
+	ctx->clk = devm_clk_get_optional_enabled(dev, "core");
+	if (IS_ERR(ctx->clk)) {
+		dev_err(dev, "failed to get DPU core clock\n");
+		return PTR_ERR(ctx->clk);
+	}
+
 	/* disable and clear interrupts before register dpu IRQ. */
 	writel(0x00, ctx->base + REG_DPU_INT_EN);
 	writel(0xff, ctx->base + REG_DPU_INT_CLR);
diff --git a/drivers/gpu/drm/sprd/sprd_dpu.h b/drivers/gpu/drm/sprd/sprd_dpu.h
index 157a78f24dc18b071602552ea9d005af66525263..d48b922de580a8a4bf07c4610c431d3321f7b810 100644
--- a/drivers/gpu/drm/sprd/sprd_dpu.h
+++ b/drivers/gpu/drm/sprd/sprd_dpu.h
@@ -44,6 +44,7 @@ enum {
  */
 struct dpu_context {
 	void __iomem *base;
+	struct clk *clk;
 	int irq;
 	u8 if_type;
 	struct videomode vm;
diff --git a/drivers/gpu/drm/sprd/sprd_dsi.c b/drivers/gpu/drm/sprd/sprd_dsi.c
index e01d1d28fe579644ec2e0c83ec9170269932adfe..2af4273a6c73185084290c9d14b8ac18914d514b 100644
--- a/drivers/gpu/drm/sprd/sprd_dsi.c
+++ b/drivers/gpu/drm/sprd/sprd_dsi.c
@@ -828,6 +828,8 @@ static void sprd_dsi_bridge_pre_enable(struct drm_bridge *bridge)
 	struct sprd_dsi *dsi = bridge_to_dsi(bridge);
 	struct dsi_context *ctx = &dsi->ctx;
 
+	clk_prepare_enable(ctx->clk);
+
 	if (ctx->enabled) {
 		drm_warn(dsi->drm, "dsi is initialized\n");
 		return;
@@ -875,6 +877,8 @@ static void sprd_dsi_bridge_post_disable(struct drm_bridge *bridge)
 	sprd_dphy_fini(ctx);
 	sprd_dsi_fini(ctx);
 
+	clk_disable_unprepare(ctx->clk);
+
 	ctx->enabled = false;
 }
 
@@ -1098,6 +1102,11 @@ static int sprd_dsi_probe(struct platform_device *pdev)
 	if (!dsi->ctx.pll.platform)
 		return -EINVAL;
 
+	dsi->ctx.clk = devm_clk_get_optional(dev, "pclk");
+	if (IS_ERR(dsi->ctx.clk))
+		return dev_err_probe(dev, PTR_ERR(dsi->ctx.clk),
+				     "failed to get pclk\n");
+
 	return mipi_dsi_host_register(&dsi->host);
 }
 
diff --git a/drivers/gpu/drm/sprd/sprd_dsi.h b/drivers/gpu/drm/sprd/sprd_dsi.h
index e5a0bd42eb548a9b85a60d79a74412b39ffa5c7c..f8bcef13ffd36aa7d98403ea22d50b8532043473 100644
--- a/drivers/gpu/drm/sprd/sprd_dsi.h
+++ b/drivers/gpu/drm/sprd/sprd_dsi.h
@@ -6,8 +6,9 @@
 #ifndef __SPRD_DSI_H__
 #define __SPRD_DSI_H__
 
-#include <linux/of.h>
+#include <linux/clk.h>
 #include <linux/device.h>
+#include <linux/of.h>
 #include <linux/regmap.h>
 #include <video/videomode.h>
 
@@ -93,6 +94,7 @@ struct dphy_pll {
 struct dsi_context {
 	void __iomem *base;
 	struct regmap *regmap;
+	struct clk *clk;
 	struct dphy_pll pll;
 	struct videomode vm;
 	bool enabled;

-- 
2.50.0
Re: [PATCH v2 10/15] drm: sprd: add clock gating support
Posted by Maxime Ripard 2 months, 2 weeks ago 
Hi,

On Tue, Jul 22, 2025 at 04:41:12PM +0200, Otto Pflüger wrote:
> Enable the DPU and DSI clocks specified in the device tree.
> Disable the DSI clock when it is not needed.
> 
> Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
> ---
>  drivers/gpu/drm/sprd/sprd_dpu.c | 7 +++++++
>  drivers/gpu/drm/sprd/sprd_dpu.h | 1 +
>  drivers/gpu/drm/sprd/sprd_dsi.c | 9 +++++++++
>  drivers/gpu/drm/sprd/sprd_dsi.h | 4 +++-
>  4 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/sprd/sprd_dpu.c b/drivers/gpu/drm/sprd/sprd_dpu.c
> index 0d9eb778794d92418b39f8535d94abde3566de43..9d274600e6a80bdfc435f6c6eff77c9dd71cb38c 100644
> --- a/drivers/gpu/drm/sprd/sprd_dpu.c
> +++ b/drivers/gpu/drm/sprd/sprd_dpu.c
> @@ -3,6 +3,7 @@
>   * Copyright (C) 2020 Unisoc Inc.
>   */
>  
> +#include <linux/clk.h>
>  #include <linux/component.h>
>  #include <linux/delay.h>
>  #include <linux/dma-buf.h>
> @@ -794,6 +795,12 @@ static int sprd_dpu_context_init(struct sprd_dpu *dpu,
>  	if (ctx->irq < 0)
>  		return ctx->irq;
>  
> +	ctx->clk = devm_clk_get_optional_enabled(dev, "core");
> +	if (IS_ERR(ctx->clk)) {
> +		dev_err(dev, "failed to get DPU core clock\n");
> +		return PTR_ERR(ctx->clk);
> +	}
> +
>  	/* disable and clear interrupts before register dpu IRQ. */
>  	writel(0x00, ctx->base + REG_DPU_INT_EN);
>  	writel(0xff, ctx->base + REG_DPU_INT_CLR);
> diff --git a/drivers/gpu/drm/sprd/sprd_dpu.h b/drivers/gpu/drm/sprd/sprd_dpu.h
> index 157a78f24dc18b071602552ea9d005af66525263..d48b922de580a8a4bf07c4610c431d3321f7b810 100644
> --- a/drivers/gpu/drm/sprd/sprd_dpu.h
> +++ b/drivers/gpu/drm/sprd/sprd_dpu.h
> @@ -44,6 +44,7 @@ enum {
>   */
>  struct dpu_context {
>  	void __iomem *base;
> +	struct clk *clk;
>  	int irq;
>  	u8 if_type;
>  	struct videomode vm;
> diff --git a/drivers/gpu/drm/sprd/sprd_dsi.c b/drivers/gpu/drm/sprd/sprd_dsi.c
> index e01d1d28fe579644ec2e0c83ec9170269932adfe..2af4273a6c73185084290c9d14b8ac18914d514b 100644
> --- a/drivers/gpu/drm/sprd/sprd_dsi.c
> +++ b/drivers/gpu/drm/sprd/sprd_dsi.c
> @@ -828,6 +828,8 @@ static void sprd_dsi_bridge_pre_enable(struct drm_bridge *bridge)
>  	struct sprd_dsi *dsi = bridge_to_dsi(bridge);
>  	struct dsi_context *ctx = &dsi->ctx;
>  
> +	clk_prepare_enable(ctx->clk);
> +
>  	if (ctx->enabled) {
>  		drm_warn(dsi->drm, "dsi is initialized\n");
>  		return;
> @@ -875,6 +877,8 @@ static void sprd_dsi_bridge_post_disable(struct drm_bridge *bridge)
>  	sprd_dphy_fini(ctx);
>  	sprd_dsi_fini(ctx);
>  
> +	clk_disable_unprepare(ctx->clk);
> +
>  	ctx->enabled = false;
>  }

I'm a bit confused. Why do you need to enable / disable that clock in
pre_enable / post_disable, if you already enabled it at probe?

Maxime
Re: [PATCH v2 10/15] drm: sprd: add clock gating support
Posted by Otto Pflüger 2 months, 2 weeks ago 
Hi Maxime,

On Wed, Jul 23, 2025 at 09:00:28AM +0200, Maxime Ripard wrote:
> Hi,
> 
> On Tue, Jul 22, 2025 at 04:41:12PM +0200, Otto Pflüger wrote:
> > Enable the DPU and DSI clocks specified in the device tree.
> > Disable the DSI clock when it is not needed.
> > 
> > Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
> > ---
> >  drivers/gpu/drm/sprd/sprd_dpu.c | 7 +++++++
> >  drivers/gpu/drm/sprd/sprd_dpu.h | 1 +
> >  drivers/gpu/drm/sprd/sprd_dsi.c | 9 +++++++++
> >  drivers/gpu/drm/sprd/sprd_dsi.h | 4 +++-
> >  4 files changed, 20 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/sprd/sprd_dpu.c b/drivers/gpu/drm/sprd/sprd_dpu.c
> > index 0d9eb778794d92418b39f8535d94abde3566de43..9d274600e6a80bdfc435f6c6eff77c9dd71cb38c 100644
> > --- a/drivers/gpu/drm/sprd/sprd_dpu.c
> > +++ b/drivers/gpu/drm/sprd/sprd_dpu.c
> > @@ -3,6 +3,7 @@
> >   * Copyright (C) 2020 Unisoc Inc.
> >   */
> >  
> > +#include <linux/clk.h>
> >  #include <linux/component.h>
> >  #include <linux/delay.h>
> >  #include <linux/dma-buf.h>
> > @@ -794,6 +795,12 @@ static int sprd_dpu_context_init(struct sprd_dpu *dpu,
> >  	if (ctx->irq < 0)
> >  		return ctx->irq;
> >  
> > +	ctx->clk = devm_clk_get_optional_enabled(dev, "core");
> > +	if (IS_ERR(ctx->clk)) {
> > +		dev_err(dev, "failed to get DPU core clock\n");
> > +		return PTR_ERR(ctx->clk);
> > +	}
> > +
> >  	/* disable and clear interrupts before register dpu IRQ. */
> >  	writel(0x00, ctx->base + REG_DPU_INT_EN);
> >  	writel(0xff, ctx->base + REG_DPU_INT_CLR);
> > diff --git a/drivers/gpu/drm/sprd/sprd_dpu.h b/drivers/gpu/drm/sprd/sprd_dpu.h
> > index 157a78f24dc18b071602552ea9d005af66525263..d48b922de580a8a4bf07c4610c431d3321f7b810 100644
> > --- a/drivers/gpu/drm/sprd/sprd_dpu.h
> > +++ b/drivers/gpu/drm/sprd/sprd_dpu.h
> > @@ -44,6 +44,7 @@ enum {
> >   */
> >  struct dpu_context {
> >  	void __iomem *base;
> > +	struct clk *clk;
> >  	int irq;
> >  	u8 if_type;
> >  	struct videomode vm;
> > diff --git a/drivers/gpu/drm/sprd/sprd_dsi.c b/drivers/gpu/drm/sprd/sprd_dsi.c
> > index e01d1d28fe579644ec2e0c83ec9170269932adfe..2af4273a6c73185084290c9d14b8ac18914d514b 100644
> > --- a/drivers/gpu/drm/sprd/sprd_dsi.c
> > +++ b/drivers/gpu/drm/sprd/sprd_dsi.c
> > @@ -828,6 +828,8 @@ static void sprd_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> >  	struct sprd_dsi *dsi = bridge_to_dsi(bridge);
> >  	struct dsi_context *ctx = &dsi->ctx;
> >  
> > +	clk_prepare_enable(ctx->clk);
> > +
> >  	if (ctx->enabled) {
> >  		drm_warn(dsi->drm, "dsi is initialized\n");
> >  		return;
> > @@ -875,6 +877,8 @@ static void sprd_dsi_bridge_post_disable(struct drm_bridge *bridge)
> >  	sprd_dphy_fini(ctx);
> >  	sprd_dsi_fini(ctx);
> >  
> > +	clk_disable_unprepare(ctx->clk);
> > +
> >  	ctx->enabled = false;
> >  }
> 
> I'm a bit confused. Why do you need to enable / disable that clock in
> pre_enable / post_disable, if you already enabled it at probe?

These are two different clocks. DPU uses devm_clk_get_optional_enabled,
while DSI uses devm_clk_get_optional and enables/disables it when
needed. Ideally both clocks should be disabled when not needed, but this
will be implemented later.

Best regards,
Otto Pflüger

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.