linux-kernel - [PATCH v3 2/2] mfd: madera: Improve handling of regulator unbinding

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Date:   Tue, 16 Jun 2020 15:06:27 +0100
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     <lee.jones@...aro.org>
CC:     <linux-kernel@...r.kernel.org>, <patches@...nsource.cirrus.com>
Subject: [PATCH v3 2/2] 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 the other MFD children depending on it.

Use the new MFD mfd_remove_devices_late functionality to split
the DCVDD regulator off from the other drivers.

Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
---

Changes since v2:
 - Moved to new mfd_remove_devices_late

Thanks,
Charles

 drivers/mfd/madera-core.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index 4724c1a01a39f..8a8d733fdce5b 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -44,7 +44,10 @@ static const char * const madera_core_supplies[] = {
 };
 
 static const struct mfd_cell madera_ldo1_devs[] = {
-	{ .name = "madera-ldo1", },
+	{
+		.name = "madera-ldo1",
+		.level = MFD_DEP_LEVEL_HIGH,
+	},
 };
 
 static const char * const cs47l15_supplies[] = {
@@ -743,18 +746,22 @@ 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_disable(madera->dev);
+	pm_runtime_get_sync(madera->dev);
 
-	clk_disable_unprepare(madera->mclk[MADERA_MCLK2].clk);
+	mfd_remove_devices(madera->dev);
+
+	pm_runtime_disable(madera->dev);
 
 	regulator_disable(madera->dcvdd);
 	regulator_put(madera->dcvdd);
 
-	mfd_remove_devices(madera->dev);
+	mfd_remove_devices_late(madera->dev);
+
+	pm_runtime_set_suspended(madera->dev);
+	pm_runtime_put_noidle(madera->dev);
+
+	clk_disable_unprepare(madera->mclk[MADERA_MCLK2].clk);
+
 	madera_enable_hard_reset(madera);
 
 	regulator_bulk_disable(madera->num_core_supplies,
-- 
2.11.0