gpio: qcom_pmic: support upstream DT

Upstream uses the gpio-ranges property to define the number of GPIOs,
support for parsing this when gpio-count is unspecified

Additionally, drop the bank-name property as it isn't used in upstream,
and we can just hardcode the bank name instead.

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/drivers/gpio/qcom_pmic_gpio.c b/drivers/gpio/qcom_pmic_gpio.c
index 7b83c67..54f4dbd 100644
--- a/drivers/gpio/qcom_pmic_gpio.c
+++ b/drivers/gpio/qcom_pmic_gpio.c
@@ -245,23 +245,48 @@
 	return 0;
 }
 
+/*
+ * Parse basic GPIO count specified via the gpio-ranges property
+ * as specified in Linux devicetrees
+ * Returns < 0 on error, otherwise gpio count
+ */
+static int qcom_gpio_of_parse_ranges(struct udevice *dev)
+{
+	int ret;
+	struct ofnode_phandle_args args;
+
+	ret = ofnode_parse_phandle_with_args(dev_ofnode(dev), "gpio-ranges",
+					     NULL, 3, 0, &args);
+	if (ret)
+		return log_msg_ret("gpio-ranges", ret);
+
+	return args.args[2];
+}
+
 static int qcom_gpio_of_to_plat(struct udevice *dev)
 {
 	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	int ret;
 
 	uc_priv->gpio_count = dev_read_u32_default(dev, "gpio-count", 0);
-	uc_priv->bank_name = dev_read_string(dev, "gpio-bank-name");
-	if (uc_priv->bank_name == NULL)
-		uc_priv->bank_name = "qcom_pmic";
+	if (!uc_priv->gpio_count) {
+		ret = qcom_gpio_of_parse_ranges(dev);
+		if (ret > 0)
+			uc_priv->gpio_count = ret;
+		else
+			return ret;
+	}
+
+	uc_priv->bank_name = "pmic";
 
 	return 0;
 }
 
 static const struct udevice_id qcom_gpio_ids[] = {
-	{ .compatible = "qcom,pm8916-gpio" },
-	{ .compatible = "qcom,pm8994-gpio" },	/* 22 GPIO's */
-	{ .compatible = "qcom,pm8998-gpio" },
-	{ .compatible = "qcom,pms405-gpio" },
+	{ .compatible = "qcom,pm8916-gpio", },
+	{ .compatible = "qcom,pm8994-gpio", },
+	{ .compatible = "qcom,pm8998-gpio", },
+	{ .compatible = "qcom,pms405-gpio", },
 	{ }
 };