linux-kernel - [PATCH v2] regulator: da9211: Use irq handler when ready

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Date:   Sun, 27 Nov 2022 22:06:02 +0100
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Support Opensource <support.opensource@...semi.com>,
        Mark Brown <broonie@...nel.org>
Cc:     Ricardo Ribalda <ribalda@...omium.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] regulator: da9211: Use irq handler when ready

If the system does not come from reset (like when it is kexec()), the
regulator might have an IRQ waiting for us.

If we enable the IRQ handler before its structures are ready, we crash.

This patch fixes:

[    1.141839] Unable to handle kernel read from unreadable memory at virtual address 0000000000000078
[    1.316096] Call trace:
[    1.316101]  blocking_notifier_call_chain+0x20/0xa8
[    1.322757] cpu cpu0: dummy supplies not allowed for exclusive requests
[    1.327823]  regulator_notifier_call_chain+0x1c/0x2c
[    1.327825]  da9211_irq_handler+0x68/0xf8
[    1.327829]  irq_thread+0x11c/0x234
[    1.327833]  kthread+0x13c/0x154

Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
regulator: da9211: Fix crash when irqs are pre-enabled

If the system does not come from reset (like when it is kexec()), the
regulator might have an IRQ waiting for us.

If we enable the IRQ handler before its structures are ready, we crash.

To: Support Opensource <support.opensource@...semi.com>
To: Liam Girdwood <lgirdwood@...il.com>
To: Mark Brown <broonie@...nel.org>
Cc: linux-kernel@...r.kernel.org
---
Changes in v2:
- Move chip_irq assignment before regulator_init (Thanks Adam)
- Reduce commit message (Thanks Mark)
- Link to v1: https://lore.kernel.org/r/20221124-da9211-v1-0-a54549aa6d3b@chromium.org
---
 drivers/regulator/da9211-regulator.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/regulator/da9211-regulator.c b/drivers/regulator/da9211-regulator.c
index e01b32d1fa17..00828f5baa97 100644
--- a/drivers/regulator/da9211-regulator.c
+++ b/drivers/regulator/da9211-regulator.c
@@ -498,6 +498,12 @@ static int da9211_i2c_probe(struct i2c_client *i2c)
 
 	chip->chip_irq = i2c->irq;
 
+	ret = da9211_regulator_init(chip);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to initialize regulator: %d\n", ret);
+		return ret;
+	}
+
 	if (chip->chip_irq != 0) {
 		ret = devm_request_threaded_irq(chip->dev, chip->chip_irq, NULL,
 					da9211_irq_handler,
@@ -512,11 +518,6 @@ static int da9211_i2c_probe(struct i2c_client *i2c)
 		dev_warn(chip->dev, "No IRQ configured\n");
 	}
 
-	ret = da9211_regulator_init(chip);
-
-	if (ret < 0)
-		dev_err(chip->dev, "Failed to initialize regulator: %d\n", ret);
-
 	return ret;
 }
 

---
base-commit: 4312098baf37ee17a8350725e6e0d0e8590252d4
change-id: 20221124-da9211-4b8904b4feb5

Best regards,
-- 
Ricardo Ribalda <ribalda@...omium.org>