[PATCH v2 2/2] mfd: madera: Improve handling of regulator unbinding

[Charles Keepax <ckeepax@opensource.cirrus.com>]

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_by_tag functionality to split
the child drivers into two groups. An "optional" group of drivers
and a core group that provide functionality to the others. Remove
the optional group first, clean up the regulators etc. then finally
remove the remaining children.

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

Changes since v1:
  - Added MFD by tag thing and removed the regulator parts

Thanks,
Charles

 drivers/mfd/madera-core.c | 73 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 58 insertions(+), 15 deletions(-)

diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
index 7e0835cb062b1..f89b8825ebc1f 100644
--- a/drivers/mfd/madera-core.c
+++ b/drivers/mfd/madera-core.c
@@ -38,6 +38,8 @@
 #define MADERA_RESET_MIN_US	2000
 #define MADERA_RESET_MAX_US	3000
 
+#define MADERA_OPTIONAL_DRIVER	1
+
 static const char * const madera_core_supplies[] = {
 	"AVDD",
 	"DBVDD1",
@@ -56,14 +58,19 @@ static const char * const cs47l15_supplies[] = {
 static const struct mfd_cell cs47l15_devs[] = {
 	{ .name = "madera-pinctrl", },
 	{ .name = "madera-irq" },
-	{ .name = "madera-gpio" },
+	{
+		.name = "madera-gpio",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
 	{
 		.name = "madera-extcon",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l15_supplies,
 		.num_parent_supplies = 1, /* We only need MICVDD */
 	},
 	{
 		.name = "cs47l15-codec",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l15_supplies,
 		.num_parent_supplies = ARRAY_SIZE(cs47l15_supplies),
 	},
@@ -80,15 +87,23 @@ static const char * const cs47l35_supplies[] = {
 static const struct mfd_cell cs47l35_devs[] = {
 	{ .name = "madera-pinctrl", },
 	{ .name = "madera-irq", },
-	{ .name = "madera-micsupp", },
-	{ .name = "madera-gpio", },
+	{
+		.name = "madera-micsupp",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
+	{
+		.name = "madera-gpio",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
 	{
 		.name = "madera-extcon",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l35_supplies,
 		.num_parent_supplies = 1, /* We only need MICVDD */
 	},
 	{
 		.name = "cs47l35-codec",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l35_supplies,
 		.num_parent_supplies = ARRAY_SIZE(cs47l35_supplies),
 	},
@@ -108,15 +123,23 @@ static const char * const cs47l85_supplies[] = {
 static const struct mfd_cell cs47l85_devs[] = {
 	{ .name = "madera-pinctrl", },
 	{ .name = "madera-irq", },
-	{ .name = "madera-micsupp" },
-	{ .name = "madera-gpio", },
+	{
+		.name = "madera-micsupp",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
+	{
+		.name = "madera-gpio",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
 	{
 		.name = "madera-extcon",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l85_supplies,
 		.num_parent_supplies = 1, /* We only need MICVDD */
 	},
 	{
 		.name = "cs47l85-codec",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l85_supplies,
 		.num_parent_supplies = ARRAY_SIZE(cs47l85_supplies),
 	},
@@ -134,15 +157,23 @@ static const char * const cs47l90_supplies[] = {
 static const struct mfd_cell cs47l90_devs[] = {
 	{ .name = "madera-pinctrl", },
 	{ .name = "madera-irq", },
-	{ .name = "madera-micsupp", },
-	{ .name = "madera-gpio", },
+	{
+		.name = "madera-micsupp",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
+	{
+		.name = "madera-gpio",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
 	{
 		.name = "madera-extcon",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l90_supplies,
 		.num_parent_supplies = 1, /* We only need MICVDD */
 	},
 	{
 		.name = "cs47l90-codec",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l90_supplies,
 		.num_parent_supplies = ARRAY_SIZE(cs47l90_supplies),
 	},
@@ -157,15 +188,23 @@ static const char * const cs47l92_supplies[] = {
 static const struct mfd_cell cs47l92_devs[] = {
 	{ .name = "madera-pinctrl" },
 	{ .name = "madera-irq", },
-	{ .name = "madera-micsupp", },
-	{ .name = "madera-gpio" },
+	{
+		.name = "madera-micsupp",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
+	{
+		.name = "madera-gpio",
+		.tag = MADERA_OPTIONAL_DRIVER,
+	},
 	{
 		.name = "madera-extcon",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l92_supplies,
 		.num_parent_supplies = 1, /* We only need MICVDD */
 	},
 	{
 		.name = "cs47l92-codec",
+		.tag = MADERA_OPTIONAL_DRIVER,
 		.parent_supplies = cs47l92_supplies,
 		.num_parent_supplies = ARRAY_SIZE(cs47l92_supplies),
 	},
@@ -743,18 +782,22 @@ 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_by_tag(madera->dev, MADERA_OPTIONAL_DRIVER);
+
+	pm_runtime_disable(madera->dev);
 
 	regulator_disable(madera->dcvdd);
 	regulator_put(madera->dcvdd);
 
 	mfd_remove_devices(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