mfd: twl-core: Disable IRQ while suspended

Since commit 6e2bd956936 ("i2c: omap: Use noirq system sleep pm ops to idle device for suspend")
on gta04 we have handle_twl4030_pih() called in situations where pm_runtime_get()
in i2c-omap.c returns -EACCES.

[   86.474365] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
[   86.485473] printk: Suspending console(s) (use no_console_suspend to debug)
[   86.555572] Disabling non-boot CPUs ...
[   86.555664] Successfully put all powerdomains to target state
[   86.563720] twl: Read failed (mod 1, reg 0x01 count 1)
[   86.563751] twl4030: I2C error -13 reading PIH ISR
[   86.563812] twl: Read failed (mod 1, reg 0x01 count 1)
[   86.563812] twl4030: I2C error -13 reading PIH ISR
[   86.563873] twl: Read failed (mod 1, reg 0x01 count 1)
[   86.563903] twl4030: I2C error -13 reading PIH ISR

This happens when we wakeup via something behing twl4030 (powerbutton or rtc
alarm). This goes on for minutes until the system is finally resumed.
Disable the irq on suspend and enable it on resume to avoid
having i2c access problems when the irq registers are checked.

Fixes: 6e2bd956936 ("i2c: omap: Use noirq system sleep pm ops to idle device for suspend")
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/twl-core.c

@@ -1245,6 +1245,28 @@ twl_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	return status;
 }
 
+static int __maybe_unused twl_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (client->irq)
+		disable_irq(client->irq);
+
+	return 0;
+}
+
+static int __maybe_unused twl_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (client->irq)
+		enable_irq(client->irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(twl_dev_pm_ops, twl_suspend, twl_resume);
+
 static const struct i2c_device_id twl_ids[] = {
 	{ "twl4030", TWL4030_VAUX2 },	/* "Triton 2" */
 	{ "twl5030", 0 },		/* T2 updated */
@@ -1262,6 +1284,7 @@ static const struct i2c_device_id twl_ids[] = {
 /* One Client Driver , 4 Clients */
 static struct i2c_driver twl_driver = {
 	.driver.name	= DRIVER_NAME,
+	.driver.pm	= &twl_dev_pm_ops,
 	.id_table	= twl_ids,
 	.probe		= twl_probe,
 	.remove		= twl_remove,