Add DT support to the 88pm800 driver, along with compatible
field for it's sub-devices (rtc, onkey and regulator)

Signed-off-by: Chao Xie <redacted>
Signed-off-by: Vaibhav Hiremath <redacted>
---
 drivers/mfd/88pm800.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/mfd/88pm800.c b/drivers/mfd/88pm800.c
index 841717a..059f01a 100644
--- a/drivers/mfd/88pm800.c
+++ b/drivers/mfd/88pm800.c

@@ -27,6 +27,7 @@
 #include <linux/mfd/core.h>
 #include <linux/mfd/88pm80x.h>
 #include <linux/slab.h>
+#include <linux/of_device.h>

 /* Interrupt Registers */
 #define PM800_INT_STATUS1              (0x05)

@@ -121,6 +122,11 @@ static const struct i2c_device_id pm80x_id_table[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pm80x_id_table);

+static const struct of_device_id pm80x_of_match_table[] = {
+       { .compatible = "marvell,88pm800", },
+       {},
+};
+
 static struct resource rtc_resources[] = {
        {
         .name = "88pm80x-rtc",

@@ -133,6 +139,7 @@ static struct resource rtc_resources[] = {
 static struct mfd_cell rtc_devs[] = {
        {
         .name = "88pm80x-rtc",
+        .of_compatible = "marvell,88pm80x-rtc",
         .num_resources = ARRAY_SIZE(rtc_resources),
         .resources = &rtc_resources[0],
         .id = -1,

@@ -151,6 +158,7 @@ static struct resource onkey_resources[] = {
 static const struct mfd_cell onkey_devs[] = {
        {
         .name = "88pm80x-onkey",
+        .of_compatible = "marvell,88pm80x-onkey",
         .num_resources = 1,
         .resources = &onkey_resources[0],
         .id = -1,

@@ -160,6 +168,7 @@ static const struct mfd_cell onkey_devs[] = {
 static const struct mfd_cell regulator_devs[] = {
        {
         .name = "88pm80x-regulator",
+        .of_compatible = "marvell,88pm80x-regulator",
         .id = -1,
        },
 };

@@ -544,8 +553,23 @@ static int pm800_probe(struct i2c_client *client,
        int ret = 0;
        struct pm80x_chip *chip;
        struct pm80x_platform_data *pdata = dev_get_platdata(&client->dev);
+       struct device_node *np = client->dev.of_node;
        struct pm80x_subchip *subchip;

+       if (!pdata && !np) {
+               dev_err(&client->dev,
+                       "pm80x requires platform data or of_node\n");
+               return -EINVAL;
+       }
+
+       if (!pdata) {
+               pdata = devm_kzalloc(&client->dev, sizeof(*pdata), GFP_KERNEL);
+               if (!pdata) {
+                       dev_err(&client->dev, "failed to allocaate memory\n");