devicetree.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v1 5/8] drm/stm: ltdc: add lvds pixel clock
@ 2023-12-21 12:30 Raphael Gallais-Pou
  2023-12-21 12:30 ` [PATCH v1 6/8] arm64: dts: st: add ltdc support on stm32mp251 Raphael Gallais-Pou
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Raphael Gallais-Pou @ 2023-12-21 12:30 UTC (permalink / raw)
  To: Laurent Pinchart, Neil Armstrong, Jessica Zhang, Sam Ravnborg,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, David Airlie,
	Daniel Vetter, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
	Maxime Coquelin, Alexandre Torgue, Yannick Fertre,
	Raphael Gallais-Pou, Philippe Cornu, Philipp Zabel, Lad Prabhakar,
	Thierry Reding
  Cc: dri-devel, devicetree, linux-kernel, linux-stm32,
	linux-arm-kernel

The STM32MP25x display subsystem presents a mux which feeds the loopback
pixel clock of the current bridge in use into the LTDC. This mux is only
accessible through sysconfig registers which is not yet available in the
STM32MP25x common clock framework.

While waiting for a complete update of the clock framework, this would
allow to use the LVDS.

Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@st.com>
Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
---
 drivers/gpu/drm/stm/ltdc.c | 18 ++++++++++++++++++
 drivers/gpu/drm/stm/ltdc.h |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 67064f47a4cb..1cf9f16e56cc 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -838,6 +838,12 @@ ltdc_crtc_mode_valid(struct drm_crtc *crtc,
 	int target_max = target + CLK_TOLERANCE_HZ;
 	int result;
 
+	if (ldev->lvds_clk) {
+		result = clk_round_rate(ldev->lvds_clk, target);
+		DRM_DEBUG_DRIVER("lvds pixclk rate target %d, available %d\n",
+				 target, result);
+	}
+
 	result = clk_round_rate(ldev->pixel_clk, target);
 
 	DRM_DEBUG_DRIVER("clk rate target %d, available %d\n", target, result);
@@ -1898,6 +1904,8 @@ void ltdc_suspend(struct drm_device *ddev)
 	clk_disable_unprepare(ldev->pixel_clk);
 	if (ldev->bus_clk)
 		clk_disable_unprepare(ldev->bus_clk);
+	if (ldev->lvds_clk)
+		clk_disable_unprepare(ldev->lvds_clk);
 }
 
 int ltdc_resume(struct drm_device *ddev)
@@ -1918,6 +1926,12 @@ int ltdc_resume(struct drm_device *ddev)
 			return -ENODEV;
 		}
 	}
+	if (ldev->lvds_clk) {
+		if (clk_prepare_enable(ldev->lvds_clk)) {
+			DRM_ERROR("Unable to prepare lvds clock\n");
+			return -ENODEV;
+		}
+	}
 
 	return 0;
 }
@@ -1989,6 +2003,10 @@ int ltdc_load(struct drm_device *ddev)
 		}
 	}
 
+	ldev->lvds_clk = devm_clk_get(dev, "lvds");
+	if (IS_ERR(ldev->lvds_clk))
+		ldev->lvds_clk = NULL;
+
 	rstc = devm_reset_control_get_exclusive(dev, NULL);
 
 	mutex_init(&ldev->err_lock);
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index 155d8e4a7c6b..662650a0fae2 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -44,6 +44,7 @@ struct ltdc_device {
 	void __iomem *regs;
 	struct regmap *regmap;
 	struct clk *pixel_clk;	/* lcd pixel clock */
+	struct clk *lvds_clk;	/* lvds pixel clock */
 	struct clk *bus_clk;	/* bus clock */
 	struct mutex err_lock;	/* protecting error_status */
 	struct ltdc_caps caps;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2023-12-21 12:31 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-12-21 12:30 [PATCH v1 5/8] drm/stm: ltdc: add lvds pixel clock Raphael Gallais-Pou
2023-12-21 12:30 ` [PATCH v1 6/8] arm64: dts: st: add ltdc support on stm32mp251 Raphael Gallais-Pou
2023-12-21 12:30 ` [PATCH v1 7/8] arm64: dts: st: add lvds support on stm32mp253 Raphael Gallais-Pou
2023-12-21 12:30 ` [PATCH v1 8/8] arm64: dts: st: add display support on stm32mp257f-ev Raphael Gallais-Pou

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).