iio:light:tsl2563 use generic fw accessors

Replace of_property_read_u32() with device_property_read_u32(),
when reading the amstaos,cover-comp-gain.This opens up the
possibility of passing the properties during platform instantiation
of the device by a suitable populated struct property_entry.
Additionally, a minor change in logic is added to remove the
of_node present check.

Signed-off-by: Vaishnav M A <[e-mail]>
Link: https://lore.kernel.org/r/20201018203552.GA816421@ubuntu
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/light/tsl2563.c

···
  */
 
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
···
 	struct iio_dev *indio_dev;
 	struct tsl2563_chip *chip;
 	struct tsl2563_platform_data *pdata = client->dev.platform_data;
-	struct device_node *np = client->dev.of_node;
 	int err = 0;
 	u8 id = 0;
 
···
 	chip->calib0 = tsl2563_calib_from_sysfs(CALIB_BASE_SYSFS);
 	chip->calib1 = tsl2563_calib_from_sysfs(CALIB_BASE_SYSFS);
 
-	if (pdata)
+	if (pdata) {
 		chip->cover_comp_gain = pdata->cover_comp_gain;
-	else if (np)
-		of_property_read_u32(np, "amstaos,cover-comp-gain",
-				     &chip->cover_comp_gain);
-	else
-		chip->cover_comp_gain = 1;
+	} else {
+		err = device_property_read_u32(&client->dev, "amstaos,cover-comp-gain",
+					       &chip->cover_comp_gain);
+		if (err)
+			chip->cover_comp_gain = 1;
+	}
 
 	dev_info(&client->dev, "model %d, rev. %d\n", id >> 4, id & 0x0f);
 	indio_dev->name = client->name;