drm/rockchip: inno-hdmi: Fix video timing HSYNC/VSYNC polarity setting for rk3036

The HSYNC/VSYNC polarity of rk3036 HDMI are controlled by GRF.
Without the polarity configuration in GRF, it can be observed
from the HDMI protocol analyzer that the H/V front/back timing
output by RK3036 HDMI are currently not in line with the specifications.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Tested-by: Heiko Stuebner <heiko@sntech.de> #rk3036-kylin
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20250422070455.432666-5-andyshrk@163.com

Author: Andy Yan

drivers/gpu/drm/rockchip/inno_hdmi.c

@@ -10,10 +10,12 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/hdmi.h>
+#include <linux/mfd/syscon.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
@@ -29,15 +31,27 @@
 
 #include "inno_hdmi.h"
 
+#define HIWORD_UPDATE(val, mask)	((val) | (mask) << 16)
+
 #define INNO_HDMI_MIN_TMDS_CLOCK  25000000U
 
+#define RK3036_GRF_SOC_CON2	0x148
+#define RK3036_HDMI_PHSYNC	BIT(4)
+#define RK3036_HDMI_PVSYNC	BIT(5)
+
+enum inno_hdmi_dev_type {
+	RK3036_HDMI,
+	RK3128_HDMI,
+};
+
 struct inno_hdmi_phy_config {
 	unsigned long pixelclock;
 	u8 pre_emphasis;
 	u8 voltage_level_control;
 };
 
 struct inno_hdmi_variant {
+	enum inno_hdmi_dev_type dev_type;
 	struct inno_hdmi_phy_config *phy_configs;
 	struct inno_hdmi_phy_config *default_phy_config;
 };
@@ -58,6 +72,7 @@ struct inno_hdmi {
 	struct clk *pclk;
 	struct clk *refclk;
 	void __iomem *regs;
+	struct regmap *grf;
 
 	struct drm_connector	connector;
 	struct rockchip_encoder	encoder;
@@ -374,7 +389,15 @@ static int inno_hdmi_config_video_csc(struct inno_hdmi *hdmi)
 static int inno_hdmi_config_video_timing(struct inno_hdmi *hdmi,
 					 struct drm_display_mode *mode)
 {
-	int value;
+	int value, psync;
+
+	if (hdmi->variant->dev_type == RK3036_HDMI) {
+		psync = mode->flags & DRM_MODE_FLAG_PHSYNC ? RK3036_HDMI_PHSYNC : 0;
+		value = HIWORD_UPDATE(psync, RK3036_HDMI_PHSYNC);
+		psync = mode->flags & DRM_MODE_FLAG_PVSYNC ? RK3036_HDMI_PVSYNC : 0;
+		value |= HIWORD_UPDATE(psync, RK3036_HDMI_PVSYNC);
+		regmap_write(hdmi->grf, RK3036_GRF_SOC_CON2, value);
+	}
 
 	/* Set detail external video timing polarity and interlace mode */
 	value = v_EXTERANL_VIDEO(1);
@@ -904,6 +927,15 @@ static int inno_hdmi_bind(struct device *dev, struct device *master,
 		goto err_disable_pclk;
 	}
 
+	if (hdmi->variant->dev_type == RK3036_HDMI) {
+		hdmi->grf = syscon_regmap_lookup_by_phandle(dev->of_node, "rockchip,grf");
+		if (IS_ERR(hdmi->grf)) {
+			ret = dev_err_probe(dev, PTR_ERR(hdmi->grf),
+					    "Unable to get rockchip,grf\n");
+			goto err_disable_clk;
+		}
+	}
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		ret = irq;
@@ -988,11 +1020,13 @@ static void inno_hdmi_remove(struct platform_device *pdev)
 }
 
 static const struct inno_hdmi_variant rk3036_inno_hdmi_variant = {
+	.dev_type = RK3036_HDMI,
 	.phy_configs = rk3036_hdmi_phy_configs,
 	.default_phy_config = &rk3036_hdmi_phy_configs[1],
 };
 
 static const struct inno_hdmi_variant rk3128_inno_hdmi_variant = {
+	.dev_type = RK3128_HDMI,
 	.phy_configs = rk3128_hdmi_phy_configs,
 	.default_phy_config = &rk3128_hdmi_phy_configs[1],
 };