Patch "mfd: ab8500-sysctrl: Handle probe deferral" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

mfd: ab8500-sysctrl: Handle probe deferral

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mfd-ab8500-sysctrl-handle-probe-deferral.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Linus Walleij <[email protected]>
Date: Sat, 7 Oct 2017 22:36:48 +0000
Subject: mfd: ab8500-sysctrl: Handle probe deferral

From: Linus Walleij <[email protected]>

[ Upstream commit 7e9c40c63933a643908d686bd89dfc2315e8c70a ]

In the current boot, clients making use of the AB8500 sysctrl may be probed before the ab8500-sysctrl driver. This gives them -EINVAL, but should rather give -EPROBE_DEFER.

Before this, the abx500 clock driver didn't probe properly, and as a result the codec driver in turn using the clocks did not probe properly. After this patch, everything probes properly.

Also add OF compatible-string probing. This driver is all device tree, so let's just make a drive-by-fix of that as well.

---
 drivers/mfd/ab8500-sysctrl.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

@@ -98,7 +98,7 @@ int ab8500_sysctrl_read(u16 reg, u8 *val
 	u8 bank;
 
 	if (sysctrl_dev == NULL)
-		return -EINVAL;
+		return -EPROBE_DEFER;
 
 	bank = (reg >> 8);
 	if (!valid_bank(bank))

@@ -114,11 +114,13 @@ int ab8500_sysctrl_write(u16 reg, u8 mas
 	u8 bank;
 
 	if (sysctrl_dev == NULL)
-		return -EINVAL;
+		return -EPROBE_DEFER;
 
 	bank = (reg >> 8);
-	if (!valid_bank(bank))
+	if (!valid_bank(bank)) {
+		pr_err("invalid bank\n");
 		return -EINVAL;
+	}
 
 	return abx500_mask_and_set_register_interruptible(sysctrl_dev, bank,
 		(u8)(reg & 0xFF), mask, value);

@@ -145,9 +147,15 @@ static int ab8500_sysctrl_remove(struct
 	return 0;
 }
 
+static const struct of_device_id ab8500_sysctrl_match[] = {
+	{ .compatible = "stericsson,ab8500-sysctrl", },
+	{}
+};
+
 static struct platform_driver ab8500_sysctrl_driver = {
 	.driver = {
 		.name = "ab8500-sysctrl",
+		.of_match_table = ab8500_sysctrl_match,
 	},
 	.probe = ab8500_sysctrl_probe,
 	.remove = ab8500_sysctrl_remove,

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mfd-ab8500-sysctrl-handle-probe-deferral.patch queue-4.9/gpio-mcp23s08-select-regmap-regmap_i2c-to-fix-build-error.patch