drm/meson: add mode selection limits against specific SoC revisions

The Amlogic S805X/Y uses the same die as the S905X, but with more
limited graphics capabilities.

This adds a soc version detection adding specific limitations on the HDMI
mode selections.

Here, we limit to HDMI 1.2a max HDMI PHY clock frequency.

Changes sinces v1:
- Moved frequency check in the vclk code, and also checks DMT modes

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[narmstrong: fixed commit message with HDMI 1.2a instead of HDMI 1.3a]
Link: https://patchwork.freedesktop.org/patch/msgid/20200428092147.13698-1-narmstrong@baylibre.com

1 files changed, 28 insertions, 1 deletions

diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 6f29fab79952..621f6de0f076 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -11,6 +11,7 @@
 #include <linux/component.h>
 #include <linux/module.h>
 #include <linux/of_graph.h>
+#include <linux/sys_soc.h>
 #include <linux/platform_device.h>
 #include <linux/soc/amlogic/meson-canvas.h>
 
@@ -183,6 +184,24 @@ static void meson_remove_framebuffers(void)
 	kfree(ap);
 }
 
+struct meson_drm_soc_attr {
+	struct meson_drm_soc_limits limits;
+	const struct soc_device_attribute *attrs;
+};
+
+static const struct meson_drm_soc_attr meson_drm_soc_attrs[] = {
+	/* S805X/S805Y HDMI PLL won't lock for HDMI PHY freq > 1,65GHz */
+	{
+		.limits = {
+			.max_hdmi_phy_freq = 1650000,
+		},
+		.attrs = (const struct soc_device_attribute []) {
+			{ .soc_id = "GXL (S805*)", },
+			{ /* sentinel */ },
+		}
+	},
+};
+
 static int meson_drv_bind_master(struct device *dev, bool has_components)
 {
 	struct platform_device *pdev = to_platform_device(dev);
@@ -191,7 +210,7 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
 	struct drm_device *drm;
 	struct resource *res;
 	void __iomem *regs;
-	int ret;
+	int ret, i;
 
 	/* Checks if an output connector is available */
 	if (!meson_vpu_has_available_connectors(dev)) {
@@ -281,6 +300,14 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
 	if (ret)
 		goto free_drm;
 
+	/* Assign limits per soc revision/package */
+	for (i = 0 ; i < ARRAY_SIZE(meson_drm_soc_attrs) ; ++i) {
+		if (soc_device_match(meson_drm_soc_attrs[i].attrs)) {
+			priv->limits = &meson_drm_soc_attrs[i].limits;
+			break;
+		}
+	}
+
 	/* Remove early framebuffers (ie. simplefb) */
 	meson_remove_framebuffers();