linux-kernel - [PATCH 1/2] mfd: madera: Improve handling of regulator unbinding

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Message-ID: <20191209113251.18692-1-ckeepax@opensource.cirrus.com>
Date:   Mon, 9 Dec 2019 11:32:50 +0000
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     <lee.jones@...aro.org>, <broonie@...nel.org>
CC:     <lgirdwood@...il.com>, <patches@...nsource.cirrus.com>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/2] mfd: madera: Improve handling of regulator unbinding

The current unbinding process for Madera has some issues. The trouble
is runtime PM is disabled as the first step of the process, but
some of the drivers release IRQs causing regmap IRQ to issue a
runtime get which fails. To allow runtime PM to remain enabled during
mfd_remove_devices, the DCVDD regulator must remain available. In
the case of external DCVDD's this is simple, the regulator can simply
be disabled/put after the call to mfd_remove_devices. However, in
the case of an internally supplied DCVDD the regulator needs to be
released after all the MFD children, except for the regulator child
itself, have been removed. This is achieved by having the regulator
driver itself do the disable/put, as it is the last driver removed from
the MFD.

Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
---
 drivers/mfd/madera-core.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index a8cfadc1fc01e..5170b55836fc1 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -730,18 +730,22 @@ int madera_dev_exit(struct madera *madera)
 	/* Prevent any IRQs being serviced while we clean up */
 	disable_irq(madera->irq);

-	/*
-	 * DCVDD could be supplied by a child node, we must disable it before
-	 * removing the children, and prevent PM runtime from turning it back on
-	 */
+	pm_runtime_get_sync(madera->dev);
+
+	mfd_remove_devices(madera->dev);
+
 	pm_runtime_disable(madera->dev);

-	clk_disable_unprepare(madera->mclk[MADERA_MCLK2].clk);
+	if (!madera->internal_dcvdd) {
+		regulator_disable(madera->dcvdd);
+		regulator_put(madera->dcvdd);
+	}

-	regulator_disable(madera->dcvdd);
-	regulator_put(madera->dcvdd);
+	pm_runtime_set_suspended(madera->dev);
+	pm_runtime_put_noidle(madera->dev);
+
+	clk_disable_unprepare(madera->mclk[MADERA_MCLK2].clk);

-	mfd_remove_devices(madera->dev);
 	madera_enable_hard_reset(madera);

 	regulator_bulk_disable(madera->num_core_supplies,
-- 
2.11.0