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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2020 NXP
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#define PHY_PLL_LOCK_WAIT_MAX_RETRIES 2000
struct imx8_pcie_phy {
struct phy *phy;
struct clk *clk;
void __iomem *base;
};
static int imx8_pcie_phy_init(struct phy *phy)
{
u32 value, retries = 0;
struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
/*
* SW workaround for ERR050442 of the iMX865 PCIe.
* Description:
* PCIE PHY can't support GEN3. GEN 1/2 are supported. Some
* buffer structures within the digital implementation in the
* PHY required for GEN3 operation are incorrect. This logic can
* be bypassed (optionally) in GEN 1/2 operation. This same
* implementation bug prevents SW form reading some status bits
* in all PCIe modes.
*
* Workaround:
* SW driver doesn't need to read the PHY status bits for proper
* PCIe operation. The buffer structure can be bypassed to
* completely support GEN1/2 operation. With some SW driver
* workarounds to read status from the PCIe PCS instead of the
* PHY, proper operation can be achieved for GEN1/2. Proper
* operation for GEN3 cannot be achieved with the SW workaround
* since the buffer structure cannot be bypassed in GEN3 mode.
*/
/* wait for pipe0_clk locked by checking status from PCS. */
for (retries = 0; retries < PHY_PLL_LOCK_WAIT_MAX_RETRIES;
retries++) {
value = readl(imx8_phy->base + 0x8188);
if (value == BIT(1))
break;
udelay(10);
}
/* setup_deskew_fifo_bypass to workaround ERR050442 */
writel(0x32, imx8_phy->base + 0xd8);
writel(0x1, imx8_phy->base + 0x480);
writel(0x0, imx8_phy->base + 0x488);
writel(0x4, imx8_phy->base + 0x73c);
writel(0x4, imx8_phy->base + 0x6ec);
/* Configure TX drive level */
writel(0x2d, imx8_phy->base + 0x404);
return 0;
}
static int imx8_pcie_phy_power_on(struct phy *phy)
{
struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
return clk_prepare_enable(imx8_phy->clk);
}
static int imx8_pcie_phy_power_off(struct phy *phy)
{
struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
clk_disable_unprepare(imx8_phy->clk);
return 0;
}
static struct phy_ops imx8_pcie_phy_ops = {
.init = imx8_pcie_phy_init,
.power_on = imx8_pcie_phy_power_on,
.power_off = imx8_pcie_phy_power_off,
.owner = THIS_MODULE,
};
static int imx8_pcie_phy_probe(struct platform_device *pdev)
{
struct phy_provider *phy_provider;
struct device *dev = &pdev->dev;
struct imx8_pcie_phy *imx8_phy;
struct resource *res;
imx8_phy = devm_kzalloc(dev, sizeof(*imx8_phy), GFP_KERNEL);
if (!imx8_phy)
return -ENOMEM;
imx8_phy->clk = devm_clk_get(dev, "phy");
if (IS_ERR(imx8_phy->clk)) {
dev_err(dev, "failed to get imx pcie phy clock\n");
return PTR_ERR(imx8_phy->clk);
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
imx8_phy->base = devm_ioremap_resource(dev, res);
if (IS_ERR(imx8_phy->base))
return PTR_ERR(imx8_phy->base);
imx8_phy->phy = devm_phy_create(dev, NULL, &imx8_pcie_phy_ops);
if (IS_ERR(imx8_phy->phy))
return PTR_ERR(imx8_phy->phy);
phy_set_drvdata(imx8_phy->phy, imx8_phy);
phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
return PTR_ERR_OR_ZERO(phy_provider);
}
static const struct of_device_id imx8_pcie_phy_of_match[] = {
{.compatible = "fsl,imx8mp-pcie-phy",},
{ },
};
MODULE_DEVICE_TABLE(of, imx8_pcie_phy_of_match);
static struct platform_driver imx8_pcie_phy_driver = {
.probe = imx8_pcie_phy_probe,
.driver = {
.name = "imx8-pcie-phy",
.of_match_table = imx8_pcie_phy_of_match,
}
};
module_platform_driver(imx8_pcie_phy_driver);
MODULE_DESCRIPTION("FSL IMX8 PCIE PHY driver");
MODULE_LICENSE("GPL");
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