Unverified Commit 82c4be41 authored by Siddharth Vadapalli's avatar Siddharth Vadapalli Committed by Krzysztof Wilczyński
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PCI: j721e: Enable ACSPCIE Refclk if "ti,syscon-acspcie-proxy-ctrl" exists 

The ACSPCIE module is capable of driving the reference clock required by
the PCIe Endpoint device. It is an alternative to on-board and external
reference clock generators. Enabling the output from the ACSPCIE module's
PAD IO Buffers requires clearing the "PAD IO disable" bits of the
ACSPCIE_PROXY_CTRL register in the CTRL_MMR register space.

Add support to enable the ACSPCIE reference clock output using the optional
device-tree property "ti,syscon-acspcie-proxy-ctrl".

Link: https://lore.kernel.org/linux-pci/20240829105316.1483684-3-s-vadapalli@ti.com


Signed-off-by: default avatarSiddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: default avatarKrzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
parent cb08c3a3

drivers/pci/controller/cadence/pci-j721e.c

+38 −1
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ enum link_status { 
#define J721E_MODE_RC			BIT(7)

#define LANE_COUNT(n)			((n) << 8)



#define ACSPCIE_PAD_DISABLE_MASK	GENMASK(1, 0)

#define GENERATION_SEL_MASK		GENMASK(1, 0)



struct j721e_pcie {
@@ -220,6 +221,36 @@ static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie, 
	return ret;

}



static int j721e_enable_acspcie_refclk(struct j721e_pcie *pcie,

				       struct regmap *syscon)

{

	struct device *dev = pcie->cdns_pcie->dev;

	struct device_node *node = dev->of_node;

	u32 mask = ACSPCIE_PAD_DISABLE_MASK;

	struct of_phandle_args args;

	u32 val;

	int ret;



	ret = of_parse_phandle_with_fixed_args(node,

					       "ti,syscon-acspcie-proxy-ctrl",

					       1, 0, &args);

	if (ret) {

		dev_err(dev,

			"ti,syscon-acspcie-proxy-ctrl has invalid arguments\n");

		return ret;

	}



	/* Clear PAD IO disable bits to enable refclk output */

	val = ~(args.args[0]);

	ret = regmap_update_bits(syscon, 0, mask, val);

	if (ret) {

		dev_err(dev, "failed to enable ACSPCIE refclk: %d\n", ret);

		return ret;

	}



	return 0;

}



static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie)

{

	struct device *dev = pcie->cdns_pcie->dev;
@@ -259,7 +290,13 @@ static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) 
		return ret;

	}



	/* Enable ACSPCIE refclk output if the optional property exists */

	syscon = syscon_regmap_lookup_by_phandle_optional(node,

						"ti,syscon-acspcie-proxy-ctrl");

	if (!syscon)

		return 0;



	return j721e_enable_acspcie_refclk(pcie, syscon);

}



static int cdns_ti_pcie_config_read(struct pci_bus *bus, unsigned int devfn,