Thread (30 messages) 30 messages, 3 authors, 2025-08-22

Re: [PATCH v4 07/13] drm/stm: ltdc: support new hardware version for STM32MP25 SoC

From: Yannick FERTRE <yannick.fertre@foss.st.com>
Date: 2025-08-22 12:57:34
Also in: dri-devel, linux-devicetree, lkml

Hi Raphael,

Thanks for the patch.

Acked-by: Yannick Fertre <yannick.fertre@foss.st.com>

Le 21/08/2025 à 13:08, Raphael Gallais-Pou a écrit :
quoted hunk ↗ jump to hunk
From: Yannick Fertre <yannick.fertre@foss.st.com>

STM32MP25 SoC features a new version of the LTDC IP.  Add its compatible
to the list of device to probe and implement its quirks.

This hardware supports a pad frequency of 150MHz and a peripheral bus
clock.

Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
---
  drivers/gpu/drm/stm/drv.c  | 12 +++++++++++-
  drivers/gpu/drm/stm/ltdc.c | 38 +++++++++++++++++++++++++++++++++++---
  drivers/gpu/drm/stm/ltdc.h |  5 +++++
  3 files changed, 51 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
index 8ebcaf953782d806a738d5a41ff1f428b0ccff78..ab00d1a6140cc32e71e10abc82f7956328b518e3 100644
--- a/drivers/gpu/drm/stm/drv.c
+++ b/drivers/gpu/drm/stm/drv.c
@@ -236,8 +236,18 @@ static void stm_drm_platform_shutdown(struct platform_device *pdev)
  	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
  }
  
+static struct ltdc_plat_data stm_drm_plat_data = {
+	.pad_max_freq_hz = 90000000,
+};
+
+static struct ltdc_plat_data stm_drm_plat_data_mp25 = {
+	.pad_max_freq_hz = 150000000,
+};
+
  static const struct of_device_id drv_dt_ids[] = {
-	{ .compatible = "st,stm32-ltdc"},
+	{ .compatible = "st,stm32-ltdc", .data = &stm_drm_plat_data, },
+	{ .compatible = "st,stm32mp251-ltdc", .data = &stm_drm_plat_data_mp25, },
+	{ .compatible = "st,stm32mp255-ltdc", .data = &stm_drm_plat_data_mp25, },
  	{ /* end node */ },
  };
  MODULE_DEVICE_TABLE(of, drv_dt_ids);
diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index ba315c66a04d72758b9d3cfcd842432877f66d3a..17548dd3484a0a3e1015c58c752b80f8892a0ff7 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -14,6 +14,7 @@
  #include <linux/interrupt.h>
  #include <linux/media-bus-format.h>
  #include <linux/module.h>
+#include <linux/of.h>
  #include <linux/of_graph.h>
  #include <linux/pinctrl/consumer.h>
  #include <linux/platform_device.h>
@@ -51,6 +52,7 @@
  #define HWVER_10300 0x010300
  #define HWVER_20101 0x020101
  #define HWVER_40100 0x040100
+#define HWVER_40101 0x040101
  
  /*
   * The address of some registers depends on the HW version: such registers have
@@ -1779,6 +1781,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
  {
  	struct ltdc_device *ldev = ddev->dev_private;
  	u32 bus_width_log2, lcr, gc2r;
+	const struct ltdc_plat_data *pdata = of_device_get_match_data(ddev->dev);
  
  	/*
  	 * at least 1 layer must be managed & the number of layers
@@ -1794,6 +1797,8 @@ static int ltdc_get_caps(struct drm_device *ddev)
  	ldev->caps.bus_width = 8 << bus_width_log2;
  	regmap_read(ldev->regmap, LTDC_IDR, &ldev->caps.hw_version);
  
+	ldev->caps.pad_max_freq_hz = pdata->pad_max_freq_hz;
+
  	switch (ldev->caps.hw_version) {
  	case HWVER_10200:
  	case HWVER_10300:
@@ -1811,7 +1816,6 @@ static int ltdc_get_caps(struct drm_device *ddev)
  		 * does not work on 2nd layer.
  		 */
  		ldev->caps.non_alpha_only_l1 = true;
-		ldev->caps.pad_max_freq_hz = 90000000;
  		if (ldev->caps.hw_version == HWVER_10200)
  			ldev->caps.pad_max_freq_hz = 65000000;
  		ldev->caps.nb_irq = 2;
@@ -1842,6 +1846,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
  		ldev->caps.fifo_threshold = false;
  		break;
  	case HWVER_40100:
+	case HWVER_40101:
  		ldev->caps.layer_ofs = LAY_OFS_1;
  		ldev->caps.layer_regs = ltdc_layer_regs_a2;
  		ldev->caps.pix_fmt_hw = ltdc_pix_fmt_a2;
@@ -1849,7 +1854,6 @@ static int ltdc_get_caps(struct drm_device *ddev)
  		ldev->caps.pix_fmt_nb = ARRAY_SIZE(ltdc_drm_fmt_a2);
  		ldev->caps.pix_fmt_flex = true;
  		ldev->caps.non_alpha_only_l1 = false;
-		ldev->caps.pad_max_freq_hz = 90000000;
  		ldev->caps.nb_irq = 2;
  		ldev->caps.ycbcr_input = true;
  		ldev->caps.ycbcr_output = true;
@@ -1872,6 +1876,8 @@ void ltdc_suspend(struct drm_device *ddev)
  
  	DRM_DEBUG_DRIVER("\n");
  	clk_disable_unprepare(ldev->pixel_clk);
+	if (ldev->bus_clk)
+		clk_disable_unprepare(ldev->bus_clk);
  }
  
  int ltdc_resume(struct drm_device *ddev)
@@ -1887,7 +1893,13 @@ int ltdc_resume(struct drm_device *ddev)
  		return ret;
  	}
  
-	return 0;
+	if (ldev->bus_clk) {
+		ret = clk_prepare_enable(ldev->bus_clk);
+		if (ret)
+			drm_err(ddev, "failed to enable bus clock (%d)\n", ret);
+	}
+
+	return ret;
  }
  
  int ltdc_load(struct drm_device *ddev)
@@ -1922,6 +1934,20 @@ int ltdc_load(struct drm_device *ddev)
  		return -ENODEV;
  	}
  
+	if (of_device_is_compatible(np, "st,stm32mp251-ltdc") ||
+	    of_device_is_compatible(np, "st,stm32mp255-ltdc")) {
+		ldev->bus_clk = devm_clk_get(dev, "bus");
+		if (IS_ERR(ldev->bus_clk))
+			return dev_err_probe(dev, PTR_ERR(ldev->bus_clk),
+					     "Unable to get bus clock\n");
+
+		ret = clk_prepare_enable(ldev->bus_clk);
+		if (ret) {
+			drm_err(ddev, "Unable to prepare bus clock\n");
+			return ret;
+		}
+	}
+
  	/* Get endpoints if any */
  	for (i = 0; i < nb_endpoints; i++) {
  		ret = drm_of_find_panel_or_bridge(np, 0, i, &panel, &bridge);
@@ -2034,6 +2060,9 @@ int ltdc_load(struct drm_device *ddev)
  
  	clk_disable_unprepare(ldev->pixel_clk);
  
+	if (ldev->bus_clk)
+		clk_disable_unprepare(ldev->bus_clk);
+
  	pinctrl_pm_select_sleep_state(ddev->dev);
  
  	pm_runtime_enable(ddev->dev);
@@ -2042,6 +2071,9 @@ int ltdc_load(struct drm_device *ddev)
  err:
  	clk_disable_unprepare(ldev->pixel_clk);
  
+	if (ldev->bus_clk)
+		clk_disable_unprepare(ldev->bus_clk);
+
  	return ret;
  }
  
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index 9d488043ffdbc652deeede71c9d57d45fb89d3c6..ddfa8ae61a7ba5dc446fae647562d0ec8e6953e1 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -40,10 +40,15 @@ struct fps_info {
  	ktime_t last_timestamp;
  };
  
+struct ltdc_plat_data {
+	int pad_max_freq_hz;	/* max frequency supported by pad */
+};
+
  struct ltdc_device {
  	void __iomem *regs;
  	struct regmap *regmap;
  	struct clk *pixel_clk;	/* lcd pixel clock */
+	struct clk *bus_clk;	/* bus clock */
  	struct mutex err_lock;	/* protecting error_status */
  	struct ltdc_caps caps;
  	u32 irq_status;
  
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help