2020-12-01 19:06:11

by Amjad Ouled-Ameur

Subject: [PATCH v2 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 <[email protected]>
Reported-by: Jerome Brunet <[email protected]>
---
changes since v1: [1]
* Moved reset_control_rearm after clk_disable_unprepare to clean things up
in reverse order of initialization for phy: amlogic: meson drivers

IMPORTANT:
This patchset depends on this patch [2], it adds reset_control_rearm() call
to the reset framework API, it has been approved by the maintainer, and
will be applied to reset/next

There is currently an immutable branch with it [3]

[1]: https://lore.kernel.org/lkml/[email protected]/
[2]: https://lore.kernel.org/lkml/[email protected]/
[3]: git://git.pengutronix.de/git/pza/linux.git reset/shared-retrigger

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..651eec41a896 100644
--- a/drivers/phy/amlogic/phy-meson8b-usb2.c
+++ b/drivers/phy/amlogic/phy-meson8b-usb2.c
@@ -154,6 +154,7 @@ 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;
}

@@ -161,6 +162,7 @@ static int phy_meson8b_usb2_power_on(struct phy *phy)
if (ret) {
dev_err(&phy->dev, "Failed to enable USB DDR clock\n");
clk_disable_unprepare(priv->clk_usb_general);
+ reset_control_rearm(priv->reset);
return ret;
}

@@ -199,6 +201,7 @@ static int phy_meson8b_usb2_power_on(struct phy *phy)
dev_warn(&phy->dev, "USB ID detect failed!\n");
clk_disable_unprepare(priv->clk_usb);
clk_disable_unprepare(priv->clk_usb_general);
+ reset_control_rearm(priv->reset);
return -EINVAL;
}
}
@@ -218,6 +221,7 @@ static int phy_meson8b_usb2_power_off(struct phy *phy)

clk_disable_unprepare(priv->clk_usb);
clk_disable_unprepare(priv->clk_usb_general);
+ reset_control_rearm(priv->reset);

return 0;
}
--
2.17.1

2020-12-05 21:45:33

by Martin Blumenstingl

Subject: Re: [PATCH v2 3/3] phy: amlogic: meson8b-usb2: fix shared reset control use

On Tue, Dec 1, 2020 at 8:02 PM Amjad Ouled-Ameur
<[email protected]> wrote:
>
> 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 <[email protected]>
> Reported-by: Jerome Brunet <[email protected]>
Reviewed-by: Martin Blumenstingl <[email protected]>
Tested-by: Martin Blumenstingl <[email protected]> #
on Odroid-C1+