[PATCH v5 10/14] regulator: Add driver for Maxim 77802 PMIC regulators

The MAX77802 PMIC has 10 high-efficiency Buck and 32 Low-dropout
(LDO) regulators. This patch adds support for all these regulators
found on the MAX77802 PMIC and is based on a driver added by Simon
Glass to the Chrome OS kernel 3.8 tree.

Signed-off-by: Javier Martinez Canillas <redacted>
Tested-by: Naveen Krishna Chatradhi <redacted>
---

Changes since v4: None

Changes since v3:
 - Set the supply_name for regulators to lookup their parent supply node.
   Suggested by Mark Brown.
 - Change Exyno5 for Exynos5420/Exynos5800 in regulator driver Kconfig.
   Suggested by Doug Anderson.

Changes since v2:
 - Use dev_warn() instead pr_warn(). Suggested by Mark Brown.
 - Add a generic function to regmap core to copy registers instead of
   having a driver-specific function. Suggested by Mark Brown.
 - Remove unnecessary probe debug log. Suggested by Mark Brown.
 - Set struct regulator_config dev field to MFD instead of the platform dev.
   Suggested by Mark Brown.
 - Read the regulators operational mode from the hardware registers instead
   of setting to normal as default on probe. Suggested by Mark Brown.
 - Remove unnecessary cross-subsystem dependencies. Suggested by Lee Jones.

Changes since v1:
 - Remove unneeded check if num_regulators != MAX77802_MAX_REGULATORS.
 - Fix .set_suspend_mode handler comment and split regulators ops for
   regulators that behave differently. Suggested by Mark Brown.
 - Use module_platform_driver() instead of having init/exit functions.
   Suggested by Mark Brown.
 - Use the new descriptor-based GPIO interface instead of the deprecated
   integer based GPIO one. Suggested by Mark Brown.
 - Look for "regulators" child node instead of "voltage-regulators" to be
   consistent with other PMIC drivers. Suggested by Mark Brown.

 drivers/mfd/max77802.c               |   8 +-
 drivers/regulator/Kconfig            |   9 +
 drivers/regulator/Makefile           |   1 +
 drivers/regulator/max77802.c         | 694 +++++++++++++++++++++++++++++++++++
 include/linux/mfd/max77802-private.h |   3 -
 5 files changed, 711 insertions(+), 4 deletions(-)
 create mode 100644 drivers/regulator/max77802.c

diff --git a/drivers/mfd/max77802.c b/drivers/mfd/max77802.c
index 3d477fb..79d36b6 100644
--- a/drivers/mfd/max77802.c
+++ b/drivers/mfd/max77802.c

@@ -228,7 +228,7 @@ static int max77802_i2c_probe(struct i2c_client *i2c,
 
 	max77802 = devm_kzalloc(&i2c->dev, sizeof(struct max77802_dev),
 				GFP_KERNEL);
-	if (max77802 == NULL)
+	if (!max77802)
 		return -ENOMEM;
 
 	i2c_set_clientdata(i2c, max77802);

@@ -315,6 +315,12 @@ static int max77802_suspend(struct device *dev)
 	if (device_may_wakeup(dev))
 		enable_irq_wake(max77802->irq);
 
+	/*
+	 * The IRQ must be disabled during suspend since due wakeup
+	 * ordering issues it may be possible that the I2C controller
+	 * is still suspended when the interrupt happens so the IRQ
+	 * handler will fail to read the I2C bus.
+	 */