[PATCH v2 7/8] drm: bridge: analogix_dp: try force hpd after plug in lookup failed

From: Yakir Yang <ykk@rock-chips.com>
To: Heiko Stuebner <heiko@sntech.de>,
	Russell King <rmk+kernel@arm.linux.org.uk>,
	Fabio Estevam <fabio.estevam@freescale.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Inki Dae <inki.dae@samsung.com>
Cc: djkurtz@google.com, dianders@google.com, seanpaul@google.com,
	joe@perches.com, Takashi Iwai <tiwai@suse.de>,
	Andrzej Hajda <a.hajda@samsung.com>,
	Thierry Reding <treding@nvidia.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	David Airlie <airlied@linux.ie>,
	Gustavo Padovan <gustavo.padovan@collabora.co.uk>,
	Seung-Woo Kim <sw0312.kim@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>,
	Kukjin Kim <kgene@kernel.org>,
	Ajay Kumar <ajaykumar.rs@samsung.com>,
	Joonyoung Shim <jy0922.shim@samsung.com>,
	Vincent Palatin <vpalatin@chromium.org>,
	Mark Yao <mark.yao@rock-chips.com>,
	Andy Yan <andy.yan@rock-chips.com>,
	ajaynumb@gmail.com, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
	linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Yakir Yang <ykk@rock-chips.com>
Subject: [PATCH v2 7/8] drm: bridge: analogix_dp: try force hpd after plug in lookup failed
Date: Fri,  7 Aug 2015 05:51:49 -0500	[thread overview]
Message-ID: <1438944709-19091-1-git-send-email-ykk@rock-chips.com> (raw)
In-Reply-To: <1438943674-18191-1-git-send-email-ykk@rock-chips.com>

Some edp screen do not have hpd signal, so we can't just return
failed when hpd plug in detect failed.

Besides TRM indicate that if HPD_STATUS(RO) is 0, AUX CH will not
work, so we need to give a force hpd action to set HPD_STATUS manually.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
---
Changes in v2: None

 drivers/gpu/drm/bridge/analogix_dp_core.c | 28 +++++++++++++++++++++++-----
 drivers/gpu/drm/bridge/analogix_dp_core.h |  1 +
 drivers/gpu/drm/bridge/analogix_dp_reg.c  |  9 +++++++++
 3 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix_dp_core.c
index 44be01d..efd810c 100644
--- a/drivers/gpu/drm/bridge/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix_dp_core.c
@@ -66,15 +66,33 @@ static int analogix_dp_detect_hpd(struct analogix_dp_device *dp)
 {
 	int timeout_loop = 0;
 
-	while (analogix_dp_get_plug_in_status(dp) != 0) {
+	while (timeout_loop < DP_TIMEOUT_LOOP_COUNT) {
+		if (analogix_dp_get_plug_in_status(dp) == 0)
+			return 0;
+
 		timeout_loop++;
-		if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
-			dev_err(dp->dev, "failed to get hpd plug status\n");
-			return -ETIMEDOUT;
-		}
 		usleep_range(10, 11);
 	}
 
+	/*
+	 * Some edp screen do not have hpd signal, so we can't just
+	 * return failed when hpd plug in detect failed.
+	 *
+	 * Besides TRM indicate that if HPD_STATUS(RO) is 0, AUX CH
+	 * will not work, so we need to give a force hpd action to
+	 * set HPD_STATUS manually.
+	 */
+	dev_dbg(dp->dev, "failed to get hpd plug status, try to force hpd\n");
+
+	analogix_dp_force_hpd(dp);
+
+	if (analogix_dp_get_plug_in_status(dp) != 0) {
+		dev_err(dp->dev, "failed to get hpd plug in status\n");
+		return -ETIMEDOUT;
+	}
+
+	dev_dbg(dp->dev, "success to get plug in status after force hpd\n");
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/bridge/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix_dp_core.h
index 713c57f..53f3973 100644
--- a/drivers/gpu/drm/bridge/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix_dp_core.h
@@ -182,6 +182,7 @@ void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp,
 				       bool enable);
 void analogix_dp_init_analog_func(struct analogix_dp_device *dp);
 void analogix_dp_init_hpd(struct analogix_dp_device *dp);
+void analogix_dp_force_hpd(struct analogix_dp_device *dp);
 enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp);
 void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp);
 void analogix_dp_reset_aux(struct analogix_dp_device *dp);
diff --git a/drivers/gpu/drm/bridge/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix_dp_reg.c
index a0fc1fb..bf7cee1 100644
--- a/drivers/gpu/drm/bridge/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix_dp_reg.c
@@ -365,6 +365,15 @@ void analogix_dp_init_hpd(struct analogix_dp_device *dp)
 	writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
 }
 
+void analogix_dp_force_hpd(struct analogix_dp_device *dp)
+{
+	u32 reg;
+
+	reg = readl(dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
+	reg = (F_HPD | HPD_CTRL);
+	writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
+}
+
 enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp)
 {
 	u32 reg;
-- 
1.9.1


