iio:adc:ti-adc12138: Switch to generic firmware properties and drop of_match_ptr

This enables using the driver with other firmware types such
as ACPI via PRP0001.

Also part of a general attempt to move IIO drivers over to generic
properties to avoid opportunities for cut and paste.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/iio/adc/ti-adc12138.c

@@ -11,6 +11,7 @@
 #include <linux/interrupt.h>
 #include <linux/completion.h>
 #include <linux/clk.h>
+#include <linux/property.h>
 #include <linux/spi/spi.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
@@ -430,7 +431,7 @@ static int adc12138_probe(struct spi_device *spi)
 		return -EINVAL;
 	}
 
-	ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
+	ret = device_property_read_u32(&spi->dev, "ti,acquisition-time",
 				       &adc->acquisition_time);
 	if (ret)
 		adc->acquisition_time = 10;
@@ -517,8 +518,6 @@ static int adc12138_remove(struct spi_device *spi)
 	return 0;
 }
 
-#ifdef CONFIG_OF
-
 static const struct of_device_id adc12138_dt_ids[] = {
 	{ .compatible = "ti,adc12130", },
 	{ .compatible = "ti,adc12132", },
@@ -527,8 +526,6 @@ static const struct of_device_id adc12138_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
 
-#endif
-
 static const struct spi_device_id adc12138_id[] = {
 	{ "adc12130", adc12130 },
 	{ "adc12132", adc12132 },
@@ -540,7 +537,7 @@ MODULE_DEVICE_TABLE(spi, adc12138_id);
 static struct spi_driver adc12138_driver = {
 	.driver = {
 		.name = "adc12138",
-		.of_match_table = of_match_ptr(adc12138_dt_ids),
+		.of_match_table = adc12138_dt_ids,
 	},
 	.probe = adc12138_probe,
 	.remove = adc12138_remove,