mfd: max77693: Fix always masked MUIC interrupts

All interrupts coming from MUIC were ignored because interrupt source
register was masked.

The Maxim 77693 has a "interrupt source" - a separate register and interrupts
which give information about PMIC block triggering the individual
interrupt (charger, topsys, MUIC, flash LED).

By default bootloader could initialize this register to "mask all"
value. In such case (observed on Trats2 board) MUIC interrupts won't be
generated regardless of their mask status. Regmap irq chip was unmasking
individual MUIC interrupts but the source was masked

Before introducing regmap irq chip this interrupt source was unmasked,
read and acked. Reading and acking is not necessary but unmasking is.

Fixes: 342d669c1ee4 ("mfd: max77693: Handle IRQs using regmap")

Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/max77693.c

@@ -250,6 +250,17 @@ static int max77693_i2c_probe(struct i2c_client *i2c,
 		goto err_irq_muic;
 	}
 
+	/* Unmask interrupts from all blocks in interrupt source register */
+	ret = regmap_update_bits(max77693->regmap,
+				MAX77693_PMIC_REG_INTSRC_MASK,
+				SRC_IRQ_ALL, (unsigned int)~SRC_IRQ_ALL);
+	if (ret < 0) {
+		dev_err(max77693->dev,
+			"Could not unmask interrupts in INTSRC: %d\n",
+			ret);
+		goto err_intsrc;
+	}
+
 	pm_runtime_set_active(max77693->dev);
 
 	ret = mfd_add_devices(max77693->dev, -1, max77693_devs,
@@ -261,6 +272,7 @@ static int max77693_i2c_probe(struct i2c_client *i2c,
 
 err_mfd:
 	mfd_remove_devices(max77693->dev);
+err_intsrc:
 	regmap_del_irq_chip(max77693->irq, max77693->irq_data_muic);
 err_irq_muic:
 	regmap_del_irq_chip(max77693->irq, max77693->irq_data_charger);

include/linux/mfd/max77693-private.h

@@ -330,6 +330,13 @@ enum max77693_irq_source {
 	MAX77693_IRQ_GROUP_NR,
 };
 
+#define SRC_IRQ_CHARGER			BIT(0)
+#define SRC_IRQ_TOP			BIT(1)
+#define SRC_IRQ_FLASH			BIT(2)
+#define SRC_IRQ_MUIC			BIT(3)
+#define SRC_IRQ_ALL			(SRC_IRQ_CHARGER | SRC_IRQ_TOP \
+						| SRC_IRQ_FLASH | SRC_IRQ_MUIC)
+
 #define LED_IRQ_FLED2_OPEN		BIT(0)
 #define LED_IRQ_FLED2_SHORT		BIT(1)
 #define LED_IRQ_FLED1_OPEN		BIT(2)