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PCI: j721e: Enable ACSPCIE Refclk if "ti,syscon-acspcie-proxy-ctrl" exists

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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: Siddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
This commit is contained in:
Siddharth Vadapalli 2024-08-29 16:23:16 +05:30 committed by Krzysztof Wilczyński
parent cb08c3a32b
commit 82c4be4168
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GPG Key ID: 7C64768D3DE334E7
1 changed files with 38 additions and 1 deletions
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39
drivers/pci/controller/cadence/pci-j721e.c
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@ -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;
}
return 0;
/* 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,