linux-kernel - [PATCH 3/3] phy: rockchip-typec: reset USB3 controller before initializing PHY

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Date:   Fri, 12 Jan 2018 18:08:24 +0800
From:   William Wu <william.wu@...k-chips.com>
To:     kishon@...com
Cc:     robh+dt@...nel.org, heiko@...ech.de, linux-kernel@...r.kernel.org,
        linux-rockchip@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        frank.wang@...k-chips.com, huangtao@...k-chips.com,
        dianders@...gle.com, briannorris@...gle.com, groeck@...gle.com,
        daniel.meng@...k-chips.com, John.Youn@...opsys.com,
        william.wu@...k-chips.com, lin.huang@...k-chips.com
Subject: [PATCH 3/3] phy: rockchip-typec: reset USB3 controller before initializing PHY

According to the RK3399 TRM, for Type-C USB start-up sequence,
we need to hold the whole USB 3.0 OTG controller in reset state
to keep the PIPE power state in P2 while initializing PHY. This
is because when initialize the Type-C PHY for USB3, we need to
configure the PHY and PMA for the selected mode of operation,
and wait for the PMA and PIPE ready, if the USB3 OTG controller
isn't in P2 state, it may cause waiting timeout.

Without this patch, waiting for the PMA and PIPE ready timeout
issue easily happens when we shutdown the Logic on RK3399 and
do the suspend/resume stress test.

Signed-off-by: William Wu <william.wu@...k-chips.com>
---
 drivers/phy/rockchip/phy-rockchip-typec.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-typec.c b/drivers/phy/rockchip/phy-rockchip-typec.c
index ee85fa0..68a5840 100644
--- a/drivers/phy/rockchip/phy-rockchip-typec.c
+++ b/drivers/phy/rockchip/phy-rockchip-typec.c
@@ -372,6 +372,7 @@ struct rockchip_typec_phy {
 	struct reset_control *uphy_rst;
 	struct reset_control *pipe_rst;
 	struct reset_control *tcphy_rst;
+	struct reset_control *otg_rst;
 	struct rockchip_usb3phy_port_cfg port_cfgs;
 	/* mutex to protect access to individual PHYs */
 	struct mutex lock;
@@ -841,10 +842,16 @@ static int rockchip_usb3_phy_power_on(struct phy *phy)
 	if (tcphy->mode == new_mode)
 		goto unlock_ret;
 
+	ret = reset_control_assert(tcphy->otg_rst);
+	if (ret < 0) {
+		dev_err(tcphy->dev, "failed to assert otg reset: %d\n", ret);
+		goto unlock_ret;
+	}
+
 	if (tcphy->mode == MODE_DISCONNECT) {
 		ret = tcphy_phy_init(tcphy, new_mode);
 		if (ret)
-			goto unlock_ret;
+			goto unlock_deassert;
 	}
 
 	/* wait TCPHY for pipe ready */
@@ -852,7 +859,7 @@ static int rockchip_usb3_phy_power_on(struct phy *phy)
 		regmap_read(tcphy->grf_regs, reg->offset, &val);
 		if (!(val & BIT(reg->enable_bit))) {
 			tcphy->mode |= new_mode & (MODE_DFP_USB | MODE_UFP_USB);
-			goto unlock_ret;
+			goto unlock_deassert;
 		}
 		usleep_range(10, 20);
 	}
@@ -862,6 +869,11 @@ static int rockchip_usb3_phy_power_on(struct phy *phy)
 
 	ret = -ETIMEDOUT;
 
+unlock_deassert:
+	ret = reset_control_deassert(tcphy->otg_rst);
+	if (ret < 0)
+		dev_err(tcphy->dev, "failed to deassert otg reset: %d\n", ret);
+
 unlock_ret:
 	mutex_unlock(&tcphy->lock);
 	return ret;
@@ -1066,6 +1078,12 @@ static int tcphy_parse_dt(struct rockchip_typec_phy *tcphy,
 		return PTR_ERR(tcphy->tcphy_rst);
 	}
 
+	tcphy->otg_rst = devm_reset_control_get(dev, "usb3-otg");
+	if (IS_ERR(tcphy->otg_rst)) {
+		dev_err(dev, "no otg_rst reset control found\n");
+		return PTR_ERR(tcphy->otg_rst);
+	}
+
 	return 0;
 }
 
-- 
2.0.0