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From: kuro <kuro.chung@ite.com.tw>
To:
CC: Allen Chen <allen.chen@ite.com.tw>, Pin-yen Lin <treapking@chromium.org>,
        Kuro Chung <kuro.chung@ite.com.tw>,
        Kenneth Haung <kenneth.hung@ite.com.tw>,
        Allen Chen <allen.chen@ite.corp-partner.google.com>,
        Andrzej Hajda
	<a.hajda@samsung.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Robert Foss
	<robert.foss@linaro.org>,
        Laurent Pinchart
	<Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej
 Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@gmail.com>, Daniel
 Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVERS"
	<dri-devel@lists.freedesktop.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: [PATCH] drm/bridge: it6505: fix hibernate to resume no display issue
Date: Wed, 21 Feb 2024 16:04:41 +0800
Message-ID: <20240221080441.190922-1-kuro.chung@ite.com.tw>
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From: kuro chung <kuro.chung@ite.com.tw>

ITE added a FIFO reset bit for input video. When system power resume,
the TTL input of it6505 may get some noise before video signal stable
and the hardware function reset is required.
But the input FIFO reset will also trigger error interrupts of output module rising.
Thus, it6505 have to wait a period can clear those expected error interrupts
caused by manual hardware reset in one interrupt handler calling to avoid interrupt looping.

Signed-off-by: Allen Chen <allen.chen@ite.corp-partner.google.com>

BUG=None
TEST=None

---
 drivers/gpu/drm/bridge/ite-it6505.c | 53 ++++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index b53da9bb65a16..86277968fab93 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -1318,6 +1318,8 @@ static void it6505_video_reset(struct it6505 *it6505)
 	it6505_set_bits(it6505, REG_DATA_MUTE_CTRL, EN_VID_MUTE, EN_VID_MUTE);
 	it6505_set_bits(it6505, REG_INFOFRAME_CTRL, EN_VID_CTRL_PKT, 0x00);
 	it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, VIDEO_RESET);
+	it6505_set_bits(it6505, REG_VID_BUS_CTRL1, TX_FIFO_RESET, 0x02);
+	it6505_set_bits(it6505, REG_VID_BUS_CTRL1, TX_FIFO_RESET, 0x00);
 	it6505_set_bits(it6505, REG_501_FIFO_CTRL, RST_501_FIFO, RST_501_FIFO);
 	it6505_set_bits(it6505, REG_501_FIFO_CTRL, RST_501_FIFO, 0x00);
 	it6505_set_bits(it6505, REG_RESET_CTRL, VIDEO_RESET, 0x00);
@@ -2480,10 +2482,6 @@ static void it6505_irq_video_fifo_error(struct it6505 *it6505)
 	struct device *dev = &it6505->client->dev;
 
 	DRM_DEV_DEBUG_DRIVER(dev, "video fifo overflow interrupt");
-	it6505->auto_train_retry = AUTO_TRAIN_RETRY;
-	flush_work(&it6505->link_works);
-	it6505_stop_hdcp(it6505);
-	it6505_video_reset(it6505);
 }
 
 static void it6505_irq_io_latch_fifo_overflow(struct it6505 *it6505)
@@ -2491,10 +2489,6 @@ static void it6505_irq_io_latch_fifo_overflow(struct it6505 *it6505)
 	struct device *dev = &it6505->client->dev;
 
 	DRM_DEV_DEBUG_DRIVER(dev, "IO latch fifo overflow interrupt");
-	it6505->auto_train_retry = AUTO_TRAIN_RETRY;
-	flush_work(&it6505->link_works);
-	it6505_stop_hdcp(it6505);
-	it6505_video_reset(it6505);
 }
 
 static bool it6505_test_bit(unsigned int bit, const unsigned int *addr)
@@ -2502,6 +2496,45 @@ static bool it6505_test_bit(unsigned int bit, const unsigned int *addr)
 	return 1 & (addr[bit / BITS_PER_BYTE] >> (bit % BITS_PER_BYTE));
 }
 
+static bool it6505_is_video_error_int(const int *int_status)
+{
+	if ((it6505_test_bit(BIT_INT_VID_FIFO_ERROR, (unsigned int *)int_status)) || (it6505_test_bit(BIT_INT_IO_FIFO_OVERFLOW, (unsigned int *)int_status)))
+		return 1;
+	return 0;
+}
+
+static void it6505_irq_video_error_handler(struct it6505 *it6505)
+{
+	struct device *dev = &it6505->client->dev;
+	int int_status[3] = {0};
+	int reg_0d;
+
+	it6505->auto_train_retry = AUTO_TRAIN_RETRY;
+	flush_work(&it6505->link_works);
+	it6505_stop_hdcp(it6505);
+	it6505_video_reset(it6505);
+
+	DRM_DEV_DEBUG_DRIVER(dev, "Video Error reset wait video...");
+
+	for (i = 0; i < 10; i++) {
+		usleep_range(10000, 11000);
+		int_status[2] = it6505_read(it6505, INT_STATUS_03);
+		reg_0d = it6505_read(it6505, REG_SYSTEM_STS);
+		it6505_write(it6505, INT_STATUS_03, int_status[2]);
+
+		DRM_DEV_DEBUG_DRIVER(dev, "reg08 = 0x%02x", int_status[2]);
+		DRM_DEV_DEBUG_DRIVER(dev, "reg0D = 0x%02x", reg_0d);
+
+		if ((reg_0d & VIDEO_STB) && (reg_0d >= 0))
+			break;
+
+		if (it6505_is_video_error_int(int_status)) {
+			it6505_video_reset(it6505);
+			DRM_DEV_DEBUG_DRIVER(dev, "Video Error reset wait video (%d)", i);
+		}
+	}
+}
+
 static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
 {
 	struct it6505 *it6505 = data;
@@ -2522,7 +2555,7 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
 		{ BIT_INT_VID_FIFO_ERROR, it6505_irq_video_fifo_error },
 		{ BIT_INT_IO_FIFO_OVERFLOW, it6505_irq_io_latch_fifo_overflow },
 	};
-	int int_status[3], i;
+	int int_status[3], i, reg_0d;
 
 	if (it6505->enable_drv_hold || !it6505->powered)
 		return IRQ_HANDLED;
@@ -2550,6 +2583,8 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
 			if (it6505_test_bit(irq_vec[i].bit, (unsigned int *)int_status))
 				irq_vec[i].handler(it6505);
 		}
+		if (it6505_is_video_error_int(int_status))
+			it6505_irq_video_error_handler(it6505);
 	}
 
 	pm_runtime_put_sync(dev);
-- 
2.25.1