linux-kernel - [PATCH v3 11/16] drm: sprd: add clock gating support

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Message-Id: <20250731-ums9230-drm-v3-11-06d4f57c4b08@abscue.de>
Date: Thu, 31 Jul 2025 17:51:24 +0200
From: Otto Pflüger <otto.pflueger@...cue.de>
To: David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Orson Zhai <orsonzhai@...il.com>, 
 Baolin Wang <baolin.wang@...ux.alibaba.com>, 
 Chunyan Zhang <zhang.lyra@...il.com>, Kevin Tang <kevin.tang@...soc.com>, 
 Liviu Dudau <Liviu.Dudau@....com>, 
 Russell King <rmk+kernel@....linux.org.uk>, Eric Anholt <eric@...olt.net>, 
 Kevin Tang <kevin3.tang@...il.com>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Otto Pflüger <otto.pflueger@...cue.de>
Subject: [PATCH v3 11/16] drm: sprd: add clock gating support

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@...cue.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 071313b605447525326f6b869bc09991d4fcd691..0edb626eb35a7eeb759c2a2f5b8428cd3b092d1f 100644
--- a/drivers/gpu/drm/sprd/sprd_dsi.c
+++ b/drivers/gpu/drm/sprd/sprd_dsi.c
@@ -832,6 +832,8 @@ 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);
+
 	sprd_dsi_init(ctx);
 	if (ctx->work_mode == DSI_MODE_VIDEO)
 		sprd_dsi_dpi_video(ctx);
@@ -886,6 +888,8 @@ static void sprd_dsi_bridge_post_disable(struct drm_bridge *bridge)
 
 	sprd_dphy_fini(ctx);
 	sprd_dsi_fini(ctx);
+
+	clk_disable_unprepare(ctx->clk);
 }
 
 static const struct drm_bridge_funcs sprd_dsi_bridge_funcs = {
@@ -1109,6 +1113,11 @@ 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 1aa609b1da33601217941390673553552f2923b1..14d06236087255f15b2704a0aff2589889fda5e9 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;
 

-- 
2.50.0