Re: [PATCH v2 3/4] PCIe: qcom: Add support to control pipe clk mux

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On 2021-06-06 02:56, Stephen Boyd wrote:
Quoting Prasad Malisetty (2021-06-05 07:40:58)
In PCIe driver pipe-clk mux needs to switch between pipe_clk
and XO for GDSC enable. This is done by setting pipe_clk mux
as parent of pipe_clk after phy init.

Just to confirm, we can't set this parent via assigned-clock-parents
property in DT?


This clock setting need be done after phy init.

Signed-off-by: Prasad Malisetty <pmaliset@xxxxxxxxxxxxxx>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 8a7a300..5cbbea4 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/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_mux;
+       struct clk *pipe_ext_src;
+       struct clk *ref_clk_src;
 };

 union qcom_pcie_resources {
@@ -1167,6 +1170,20 @@ static int qcom_pcie_get_resources_2_7_0(struct qcom_pcie *pcie)
        if (ret < 0)
                return ret;

+ if (of_device_is_compatible(dev->of_node, "qcom,pcie-sc7280")) {
+               res->pipe_clk_mux = devm_clk_get(dev, "pipe_src");
+               if (IS_ERR(res->pipe_clk_mux))
+                       return PTR_ERR(res->pipe_clk_mux);
+
+               res->pipe_ext_src = devm_clk_get(dev, "pipe_ext");
+               if (IS_ERR(res->pipe_ext_src))
+                       return PTR_ERR(res->pipe_ext_src);
+
+               res->ref_clk_src = devm_clk_get(dev, "ref");

Is this going to be used by any code?

Yes, ref clock will be used in system suspend case. currently system suspend changes are in under validation.

+               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);
 }
@@ -1255,6 +1272,11 @@ static void qcom_pcie_deinit_2_7_0(struct qcom_pcie *pcie)
 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;
+       struct dw_pcie *pci = pcie->pci;
+       struct device *dev = pci->dev;
+
+       if (of_device_is_compatible(dev->of_node, "qcom,pcie-sc7280"))
+               clk_set_parent(res->pipe_clk_mux, res->pipe_ext_src);

        return clk_prepare_enable(res->pipe_clk);
 }
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project




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