mfd: adp5520: Restore mode bits on resume

The adp5520 unfortunately also clears the BL_EN bit when the nSTNDBY bit is
cleared. So we need to make sure to restore it during resume if it was set
before suspend.

Cc: [e-mail]
Signed-off-by: Lars-Peter Clausen <[e-mail]>
Acked-by: Michael Hennerich <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/mfd/adp5520.c

···
 	struct blocking_notifier_head notifier_list;
 	int irq;
 	unsigned long id;
+	uint8_t mode;
 };
 
 static int __adp5520_read(struct i2c_client *client,
···
 	struct i2c_client *client = to_i2c_client(dev);
 	struct adp5520_chip *chip = dev_get_drvdata(&client->dev);
 
-	adp5520_clr_bits(chip->dev, ADP5520_MODE_STATUS, ADP5520_nSTNBY);
+	adp5520_read(chip->dev, ADP5520_MODE_STATUS, &chip->mode);
+	/* All other bits are W1C */
+	chip->mode &= ADP5520_BL_EN | ADP5520_DIM_EN | ADP5520_nSTNBY;
+	adp5520_write(chip->dev, ADP5520_MODE_STATUS, 0);
 	return 0;
 }
 
···
 	struct i2c_client *client = to_i2c_client(dev);
 	struct adp5520_chip *chip = dev_get_drvdata(&client->dev);
 
-	adp5520_set_bits(chip->dev, ADP5520_MODE_STATUS, ADP5520_nSTNBY);
+	adp5520_write(chip->dev, ADP5520_MODE_STATUS, chip->mode);
 	return 0;
 }
 #endif