linux-kernel - [PATCH v6 02/23] mfd: max77686: Add power management support

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Message-Id: <1404467722-26687-3-git-send-email-javier.martinez@collabora.co.uk>
Date:	Fri,  4 Jul 2014 11:55:01 +0200
From:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
To:	Lee Jones <lee.jones@...aro.org>
Cc:	Mark Brown <broonie@...nel.org>,
	Mike Turquette <mturquette@...aro.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Doug Anderson <dianders@...omium.org>,
	Olof Johansson <olof@...om.net>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Yadwinder Singh Brar <yadi.brar01@...il.com>,
	Tushar Behera <trblinux@...il.com>,
	Andreas Farber <afaerber@...e.de>,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Subject: [PATCH v6 02/23] mfd: max77686: Add power management support

The driver doesn't have PM operations defined so add a suspend
and resume function handlers to allow the PMIC IRQ to wakeup
the system when it is put into a sleep state.

Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
---
 drivers/mfd/max77686.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c
index 3cb41d0..a38e9ee 100644
--- a/drivers/mfd/max77686.c
+++ b/drivers/mfd/max77686.c
@@ -240,10 +240,50 @@ static const struct i2c_device_id max77686_i2c_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, max77686_i2c_id);
 
+#ifdef CONFIG_PM_SLEEP
+static int max77686_suspend(struct device *dev)
+{
+	struct i2c_client *i2c = container_of(dev, struct i2c_client, dev);
+	struct max77686_dev *max77686 = i2c_get_clientdata(i2c);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(max77686->irq);
+
+	/*
+	 * IRQ must be disabled during suspend because if it happens
+	 * while suspended it will be handled before resuming I2C.
+	 *
+	 * When device is woken up from suspend (e.g. by RTC wake alarm),
+	 * an interrupt occurs before resuming I2C bus controller.
+	 * Interrupt handler tries to read registers but this read
+	 * will fail because I2C is still suspended.
+	 */
+	disable_irq(max77686->irq);
+
+	return 0;
+}
+
+static int max77686_resume(struct device *dev)
+{
+	struct i2c_client *i2c = container_of(dev, struct i2c_client, dev);
+	struct max77686_dev *max77686 = i2c_get_clientdata(i2c);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(max77686->irq);
+
+	enable_irq(max77686->irq);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(max77686_pm, max77686_suspend, max77686_resume);
+
 static struct i2c_driver max77686_i2c_driver = {
 	.driver = {
 		   .name = "max77686",
 		   .owner = THIS_MODULE,
+		   .pm = &max77686_pm,
 		   .of_match_table = of_match_ptr(max77686_pmic_dt_match),
 	},
 	.probe = max77686_i2c_probe,
-- 
2.0.0.rc2

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