PCI: qcom: Switch pcie_1_pipe_clk_src after PHY init in SC7280

On the SC7280, the clock source for gcc_pcie_1_pipe_clk_src must be the
TCXO while gdsc is enabled. After PHY init successful clock source should
switch to pipe clock for gcc_pcie_1_pipe_clk_src.

Link: https://lore.kernel.org/r/1633628923-25047-6-git-send-email-pmaliset@codeaurora.org
Signed-off-by: Prasad Malisetty <pmaliset@codeaurora.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>

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

@@ -166,6 +166,9 @@ struct qcom_pcie_resources_2_7_0 {
 	struct regulator_bulk_data supplies[2];
 	struct reset_control *pci_reset;
 	struct clk *pipe_clk;
+	struct clk *pipe_clk_src;
+	struct clk *phy_pipe_clk;
+	struct clk *ref_clk_src;
 };
 
 union qcom_pcie_resources {
@@ -191,6 +194,7 @@ struct qcom_pcie_ops {
 
 struct qcom_pcie_cfg {
 	const struct qcom_pcie_ops *ops;
+	unsigned int pipe_clk_need_muxing:1;
 };
 
 struct qcom_pcie {
@@ -201,6 +205,7 @@ struct qcom_pcie {
 	struct phy *phy;
 	struct gpio_desc *reset;
 	const struct qcom_pcie_ops *ops;
+	unsigned int pipe_clk_need_muxing:1;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
@@ -1171,6 +1176,20 @@ static int qcom_pcie_get_resources_2_7_0(struct qcom_pcie *pcie)
 	if (ret < 0)
 		return ret;
 
+	if (pcie->pipe_clk_need_muxing) {
+		res->pipe_clk_src = devm_clk_get(dev, "pipe_mux");
+		if (IS_ERR(res->pipe_clk_src))
+			return PTR_ERR(res->pipe_clk_src);
+
+		res->phy_pipe_clk = devm_clk_get(dev, "phy_pipe");
+		if (IS_ERR(res->phy_pipe_clk))
+			return PTR_ERR(res->phy_pipe_clk);
+
+		res->ref_clk_src = devm_clk_get(dev, "ref");
+		if (IS_ERR(res->ref_clk_src))
+			return PTR_ERR(res->ref_clk_src);
+	}
+
 	res->pipe_clk = devm_clk_get(dev, "pipe");
 	return PTR_ERR_OR_ZERO(res->pipe_clk);
 }
@@ -1189,6 +1208,10 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
 		return ret;
 	}
 
+	/* Set TCXO as clock source for pcie_pipe_clk_src */
+	if (pcie->pipe_clk_need_muxing)
+		clk_set_parent(res->pipe_clk_src, res->ref_clk_src);
+
 	ret = clk_bulk_prepare_enable(res->num_clks, res->clks);
 	if (ret < 0)
 		goto err_disable_regulators;
@@ -1260,6 +1283,10 @@ static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
 {
 	struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
 
+	/* Set pipe clock as clock source for pcie_pipe_clk_src */
+	if (pcie->pipe_clk_need_muxing)
+		clk_set_parent(res->pipe_clk_src, res->phy_pipe_clk);
+
 	return clk_prepare_enable(res->pipe_clk);
 }
 
@@ -1490,6 +1517,7 @@ static const struct qcom_pcie_cfg sm8250_cfg = {
 
 static const struct qcom_pcie_cfg sc7280_cfg = {
 	.ops = &ops_1_9_0,
+	.pipe_clk_need_muxing = true,
 };
 
 static const struct dw_pcie_ops dw_pcie_ops = {
@@ -1532,6 +1560,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 	}
 
 	pcie->ops = pcie_cfg->ops;
+	pcie->pipe_clk_need_muxing = pcie_cfg->pipe_clk_need_muxing;
 
 	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
 	if (IS_ERR(pcie->reset)) {