From 18f77393796848e68909e65d692c1d1436f06e06 Mon Sep 17 00:00:00 2001
From: Martin Kaiser <martin@kaiser.cx>
Date: Tue, 17 Oct 2017 22:53:08 +0200
Subject: [PATCH] mfd: fsl-imx25: Clean up irq settings during removal
Git-commit: 18f77393796848e68909e65d692c1d1436f06e06
Patch-mainline: v4.15-rc1
References: bsc#1051510

When fsl-imx25-tsadc is compiled as a module, loading, unloading and
reloading the module will lead to a crash.

Unable to handle kernel paging request at virtual address bf005430
[<c004df6c>] (irq_find_matching_fwspec)
   from [<c028d5ec>] (of_irq_get+0x58/0x74)
[<c028d594>] (of_irq_get)
   from [<c01ff970>] (platform_get_irq+0x48/0xc8)
[<c01ff928>] (platform_get_irq)
   from [<bf00e33c>] (mx25_tsadc_probe+0x220/0x2f4 [fsl_imx25_tsadc])

irq_find_matching_fwspec() loops over all registered irq domains. The
irq domain is still registered from last time the module was loaded but
the pointer to its operations is invalid after the module was unloaded.

Add a removal function which clears the irq handler and removes the irq
domain. With this cleanup in place, it's possible to unload and reload
the module.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mfd/fsl-imx25-tsadc.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/mfd/fsl-imx25-tsadc.c
+++ b/drivers/mfd/fsl-imx25-tsadc.c
@@ -183,6 +183,19 @@ static int mx25_tsadc_probe(struct platf
 	return 0;
 }
 
+static int mx25_tsadc_remove(struct platform_device *pdev)
+{
+	struct mx25_tsadc *tsadc = platform_get_drvdata(pdev);
+	int irq = platform_get_irq(pdev, 0);
+
+	if (irq) {
+		irq_set_chained_handler_and_data(irq, NULL, NULL);
+		irq_domain_remove(tsadc->domain);
+	}
+
+	return 0;
+}
+
 static const struct of_device_id mx25_tsadc_ids[] = {
 	{ .compatible = "fsl,imx25-tsadc" },
 	{ /* Sentinel */ }
@@ -195,6 +208,7 @@ static struct platform_driver mx25_tsadc
 		.of_match_table = of_match_ptr(mx25_tsadc_ids),
 	},
 	.probe = mx25_tsadc_probe,
+	.remove = mx25_tsadc_remove,
 };
 module_platform_driver(mx25_tsadc_driver);