[PATCH AUTOSEL 6.15 005/110] drm/rockchip: inno-hdmi: Fix video timing HSYNC/VSYNC polarity setting for rk3036

[Sasha Levin <sashal@kernel.org>]

From: Andy Yan <andy.yan@rock-chips.com>

[ Upstream commit ad10b82c2bcac7f87ac6eaecfca33378b43425ee ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

## Analysis Based on my analysis of the commit message and code changes,
my answer is: **YES**, this commit should be backported to stable kernel
trees. ## Detailed Explanation: ### 1. **Bug Fix Nature** This commit
fixes a specific bug where HSYNC/VSYNC polarity settings for RK3036 HDMI
were not being properly configured. According to the commit message,
"the H/V front/back timing output by RK3036 HDMI are currently not in
line with the specifications" when observed on an HDMI protocol
analyzer. This is a clear functionality bug affecting users. ### 2.
**Hardware-Specific Fix** The fix addresses a hardware requirement
specific to RK3036 where the HSYNC/VSYNC polarity must be configured
through the GRF (General Register File) rather than just through the
HDMI controller registers. The code shows: ```c + 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); + } ``` ### 3. **Minimal and Contained
Changes** The fix is: - Small in scope (adds ~30 lines of code) -
Contained to the specific hardware variant (RK3036) - Does not affect
other hardware variants (protected by `if (hdmi->variant->dev_type ==
RK3036_HDMI)`) - Only adds necessary GRF configuration without changing
existing logic ### 4. **Long-standing Issue** The driver was originally
added in 2016 (commit 412d4ae6b7a5), and this polarity issue has been
present since then. This suggests users of RK3036 hardware have been
experiencing incorrect HDMI timing output for years. ### 5. **Similar to
Previously Backported Fixes** Looking at the similar commits provided: -
Commit #1 (47a145c03484) fixed video timing issues and was backported
(YES) - Commit #2 (604be85547ce) fixed sync polarities for different
Rockchip hardware and was backported (YES) This commit follows the same
pattern of fixing display timing/polarity issues in Rockchip display
drivers. ### 6. **No Risk of Regression** The change: - Only affects
RK3036 hardware when specifically identified - Adds proper hardware
configuration that was missing - Does not modify existing behavior for
other variants - Has been tested on actual hardware (per the Tested-by
tag) ### 7. **Clear User Impact** Without this fix, RK3036 HDMI users
experience: - Incorrect video timing that doesn't meet HDMI
specifications - Potential display compatibility issues - Unstable or
non-functional HDMI output with certain displays This directly impacts
the usability of HDMI output on RK3036-based devices, making it an
important fix for stable users. The commit meets all criteria for stable
backporting: it's a clear bug fix, minimal in scope, has no
architectural changes, fixes a real user-visible issue, and has very low
risk of introducing regressions.

 drivers/gpu/drm/rockchip/inno_hdmi.c | 36 +++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/inno_hdmi.c b/drivers/gpu/drm/rockchip/inno_hdmi.c
index 483ecfeaebb08..87dfd30001583 100644
--- a/drivers/gpu/drm/rockchip/inno_hdmi.c
+++ b/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>
@@ -29,8 +31,19 @@
 
 #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;
@@ -38,6 +51,7 @@ struct inno_hdmi_phy_config {
 };
 
 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);
@@ -911,6 +934,15 @@ 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;
@@ -995,11 +1027,13 @@ 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],
 };
-- 
2.39.5