linux-kernel - [PATCH 3/3] phy: amlogic: meson8b-usb2: fix shared reset control use

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Date:   Fri, 13 Nov 2020 01:05:08 +0100
From:   Amjad Ouled-Ameur <aouledameur@...libre.com>
To:     Kevin Hilman <khilman@...libre.com>
Cc:     Amjad Ouled-Ameur <aouledameur@...libre.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Felipe Balbi <balbi@...nel.org>,
        Jerome Brunet <jbrunet@...libre.com>,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: [PATCH 3/3] phy: amlogic: meson8b-usb2: fix shared reset control use

Use reset_control_rearm() call if an error occurs in case
phy_meson8b_usb2_power_on() fails after reset() has been called, or in
case phy_meson8b_usb2_power_off() is called i.e the resource is no longer
used and the reset line may be triggered again by other devices.

reset_control_rearm() keeps use of triggered_count sane in the reset
framework, use of reset_control_reset() on shared reset line should
be balanced with reset_control_rearm().

Signed-off-by: Amjad Ouled-Ameur <aouledameur@...libre.com>
Reported-by: Jerome Brunet <jbrunet@...libre.com>
---
Important:
Please DO NOT merge before this patch [0] is merged, it adds 
reset_control_rearm() call to the reset framework API.

 drivers/phy/amlogic/phy-meson8b-usb2.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/phy/amlogic/phy-meson8b-usb2.c b/drivers/phy/amlogic/phy-meson8b-usb2.c
index 03c061dd5f0d..2a6c53f52423 100644
--- a/drivers/phy/amlogic/phy-meson8b-usb2.c
+++ b/drivers/phy/amlogic/phy-meson8b-usb2.c
@@ -154,12 +154,14 @@ static int phy_meson8b_usb2_power_on(struct phy *phy)
 	ret = clk_prepare_enable(priv->clk_usb_general);
 	if (ret) {
 		dev_err(&phy->dev, "Failed to enable USB general clock\n");
+		reset_control_rearm(priv->reset);
 		return ret;
 	}
 
 	ret = clk_prepare_enable(priv->clk_usb);
 	if (ret) {
 		dev_err(&phy->dev, "Failed to enable USB DDR clock\n");
+		reset_control_rearm(priv->reset);
 		clk_disable_unprepare(priv->clk_usb_general);
 		return ret;
 	}
@@ -197,6 +199,7 @@ static int phy_meson8b_usb2_power_on(struct phy *phy)
 			regmap_read(priv->regmap, REG_ADP_BC, &reg);
 			if (reg & REG_ADP_BC_ACA_PIN_FLOAT) {
 				dev_warn(&phy->dev, "USB ID detect failed!\n");
+				reset_control_rearm(priv->reset);
 				clk_disable_unprepare(priv->clk_usb);
 				clk_disable_unprepare(priv->clk_usb_general);
 				return -EINVAL;
@@ -216,6 +219,7 @@ static int phy_meson8b_usb2_power_off(struct phy *phy)
 				   REG_DBG_UART_SET_IDDQ,
 				   REG_DBG_UART_SET_IDDQ);
 
+	reset_control_rearm(priv->reset);
 	clk_disable_unprepare(priv->clk_usb);
 	clk_disable_unprepare(priv->clk_usb_general);
 
-- 
2.17.1