PCI: qcom: Add missing reset for ipq806x

Add missing ext reset used by ipq8064 SoC in PCIe qcom driver.

Link: https://lore.kernel.org/r/20200615210608.21469-5-ansuelsmth@gmail.com
Fixes: 82a823833f ("PCI: qcom: Add Qualcomm PCIe controller driver")
Signed-off-by: Sham Muthayyan <smuthayy@codeaurora.org>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: stable@vger.kernel.org # v4.5+

drivers/pci/controller/dwc/pcie-qcom.c

@@ -95,6 +95,7 @@ struct qcom_pcie_resources_2_1_0 {
 	struct reset_control *ahb_reset;
 	struct reset_control *por_reset;
 	struct reset_control *phy_reset;
+	struct reset_control *ext_reset;
 	struct regulator_bulk_data supplies[QCOM_PCIE_2_1_0_MAX_SUPPLY];
 };
 
@@ -272,6 +273,10 @@ static int qcom_pcie_get_resources_2_1_0(struct qcom_pcie *pcie)
 	if (IS_ERR(res->por_reset))
 		return PTR_ERR(res->por_reset);
 
+	res->ext_reset = devm_reset_control_get_optional_exclusive(dev, "ext");
+	if (IS_ERR(res->ext_reset))
+		return PTR_ERR(res->ext_reset);
+
 	res->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
 	return PTR_ERR_OR_ZERO(res->phy_reset);
 }
@@ -285,6 +290,7 @@ static void qcom_pcie_deinit_2_1_0(struct qcom_pcie *pcie)
 	reset_control_assert(res->axi_reset);
 	reset_control_assert(res->ahb_reset);
 	reset_control_assert(res->por_reset);
+	reset_control_assert(res->ext_reset);
 	reset_control_assert(res->phy_reset);
 	clk_disable_unprepare(res->iface_clk);
 	clk_disable_unprepare(res->core_clk);
@@ -343,6 +349,12 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
 		goto err_deassert_ahb;
 	}
 
+	ret = reset_control_deassert(res->ext_reset);
+	if (ret) {
+		dev_err(dev, "cannot deassert ext reset\n");
+		goto err_deassert_ahb;
+	}
+
 	/* enable PCIe clocks and resets */
 	val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
 	val &= ~BIT(0);