[DRIVER] pca953x: add dts property gpio-base

drivers/gpio/gpio-pca953x.c

@@ -949,6 +949,8 @@ static int pca953x_probe(struct i2c_client *client,
 			 const struct i2c_device_id *i2c_id)
 {
 	struct pca953x_platform_data *pdata;
+	struct device *dev = &client->dev;
+	struct device_node *np = dev->of_node;
 	struct pca953x_chip *chip;
 	int irq_base = 0;
 	int ret;
@@ -967,9 +969,14 @@ static int pca953x_probe(struct i2c_client *client,
 		invert = pdata->invert;
 		chip->names = pdata->names;
 	} else {
+		int gpio_base;
 		struct gpio_desc *reset_gpio;
 
 		chip->gpio_start = -1;
+		if (of_property_read_u32(np, "gpio-base", &gpio_base) == 0) {
+			chip->gpio_start = gpio_base;
+			dev_info(&client->dev, "GPIO expander base number will be %d\n", gpio_base);
+		}
 		irq_base = 0;
 
 		/*