linux-kernel - [PATCH] Revert "usb: dwc3: meson-g12a: fix shared reset control use"

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Message-Id: <20200827144810.26657-1-aouledameur@baylibre.com>
Date:   Thu, 27 Aug 2020 16:48:10 +0200
From:   Amjad Ouled-Ameur <aouledameur@...libre.com>
To:     Felipe Balbi <balbi@...nel.org>
Cc:     Amjad Ouled-Ameur <aouledameur@...libre.com>,
        Dan Robertson <dan@...obertson.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kevin Hilman <khilman@...libre.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-usb@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Revert "usb: dwc3: meson-g12a: fix shared reset control use"

This reverts commit 7a410953d1fb4dbe91ffcfdee9cbbf889d19b0d7.

This commit breaks USB on meson-gxl-s905x-libretech-cc. Reverting
the change solves the issue.

In fact, according to the reset framework code, consumers must not use
reset_control_(de)assert() on shared reset lines when reset_control_reset
has been used, and vice-versa.

Moreover, with this commit, usb is not guaranted to be reset since the
reset is likely to be initially deasserted.

Reverting the commit will bring back the suspend warning mentioned in the
commit description. Nevertheless, a warning is much less critical than
breaking dwc3-meson-g12a USB completely. We will address the warning
issue in another way as a 2nd step.

Signed-off-by: Amjad Ouled-Ameur <aouledameur@...libre.com>
Reported-by: Jerome Brunet <jbrunet@...libre.com>
---
 drivers/usb/dwc3/dwc3-meson-g12a.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c b/drivers/usb/dwc3/dwc3-meson-g12a.c
index 88b75b5a039c..1f7f4d88ed9d 100644
--- a/drivers/usb/dwc3/dwc3-meson-g12a.c
+++ b/drivers/usb/dwc3/dwc3-meson-g12a.c
@@ -737,13 +737,13 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev)
 		goto err_disable_clks;
 	}
 
-	ret = reset_control_deassert(priv->reset);
+	ret = reset_control_reset(priv->reset);
 	if (ret)
-		goto err_assert_reset;
+		goto err_disable_clks;
 
 	ret = dwc3_meson_g12a_get_phys(priv);
 	if (ret)
-		goto err_assert_reset;
+		goto err_disable_clks;
 
 	ret = priv->drvdata->setup_regmaps(priv, base);
 	if (ret)
@@ -752,7 +752,7 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev)
 	if (priv->vbus) {
 		ret = regulator_enable(priv->vbus);
 		if (ret)
-			goto err_assert_reset;
+			goto err_disable_clks;
 	}
 
 	/* Get dr_mode */
@@ -765,13 +765,13 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev)
 
 	ret = priv->drvdata->usb_init(priv);
 	if (ret)
-		goto err_assert_reset;
+		goto err_disable_clks;
 
 	/* Init PHYs */
 	for (i = 0 ; i < PHY_COUNT ; ++i) {
 		ret = phy_init(priv->phys[i]);
 		if (ret)
-			goto err_assert_reset;
+			goto err_disable_clks;
 	}
 
 	/* Set PHY Power */
@@ -809,9 +809,6 @@ static int dwc3_meson_g12a_probe(struct platform_device *pdev)
 	for (i = 0 ; i < PHY_COUNT ; ++i)
 		phy_exit(priv->phys[i]);
 
-err_assert_reset:
-	reset_control_assert(priv->reset);
-
 err_disable_clks:
 	clk_bulk_disable_unprepare(priv->drvdata->num_clks,
 				   priv->drvdata->clks);
-- 
2.17.1