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Message-ID: <CAGXv+5GZcgNU3ayKPeKxvA4nfXmYDLG=08ihRngmOAZbBLzRBw@mail.gmail.com>
Date: Fri, 18 Mar 2022 17:59:54 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Jianjun Wang <jianjun.wang@...iatek.com>
Cc: Chunfeng Yun <chunfeng.yun@...iatek.com>,
Kishon Vijay Abraham I <kishon@...com>,
Vinod Koul <vkoul@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
linux-arm-kernel@...ts.infradead.org,
linux-mediatek@...ts.infradead.org, linux-phy@...ts.infradead.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
rex-bc.chen@...iatek.com, Randy.Wu@...iatek.com,
jieyy.yang@...iatek.com, chuanjia.liu@...iatek.com,
qizhong.cheng@...iatek.com, jian.yang@...iatek.com
Subject: Re: [PATCH v2 2/2] phy: mediatek: Add PCIe PHY driver
On Fri, Mar 18, 2022 at 5:54 PM Jianjun Wang <jianjun.wang@...iatek.com> wrote:
>
> Add PCIe GEN3 PHY driver support on MediaTek chipsets.
>
> Signed-off-by: Jianjun Wang <jianjun.wang@...iatek.com>
> ---
> drivers/phy/mediatek/Kconfig | 11 ++
> drivers/phy/mediatek/Makefile | 1 +
> drivers/phy/mediatek/phy-mtk-pcie.c | 246 ++++++++++++++++++++++++++++
> 3 files changed, 258 insertions(+)
> create mode 100644 drivers/phy/mediatek/phy-mtk-pcie.c
>
> diff --git a/drivers/phy/mediatek/Kconfig b/drivers/phy/mediatek/Kconfig
> index 55f8e6c048ab..387ed1b3f2cc 100644
> --- a/drivers/phy/mediatek/Kconfig
> +++ b/drivers/phy/mediatek/Kconfig
> @@ -55,3 +55,14 @@ config PHY_MTK_MIPI_DSI
> select GENERIC_PHY
> help
> Support MIPI DSI for Mediatek SoCs.
> +
> +config PHY_MTK_PCIE
> + tristate "MediaTek PCIe-PHY Driver"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + depends on OF
> + select GENERIC_PHY
> + help
> + Say 'Y' here to add support for MediaTek PCIe PHY driver.
> + This driver create the basic PHY instance and provides initialize
> + callback for PCIe GEN3 port, it supports software efuse
> + initialization.
> diff --git a/drivers/phy/mediatek/Makefile b/drivers/phy/mediatek/Makefile
> index ace660fbed3a..788c13147f63 100644
> --- a/drivers/phy/mediatek/Makefile
> +++ b/drivers/phy/mediatek/Makefile
> @@ -6,6 +6,7 @@
> obj-$(CONFIG_PHY_MTK_TPHY) += phy-mtk-tphy.o
> obj-$(CONFIG_PHY_MTK_UFS) += phy-mtk-ufs.o
> obj-$(CONFIG_PHY_MTK_XSPHY) += phy-mtk-xsphy.o
> +obj-$(CONFIG_PHY_MTK_PCIE) += phy-mtk-pcie.o
>
> phy-mtk-hdmi-drv-y := phy-mtk-hdmi.o
> phy-mtk-hdmi-drv-y += phy-mtk-hdmi-mt2701.o
> diff --git a/drivers/phy/mediatek/phy-mtk-pcie.c b/drivers/phy/mediatek/phy-mtk-pcie.c
> new file mode 100644
> index 000000000000..0f5d7c7e2b7e
> --- /dev/null
> +++ b/drivers/phy/mediatek/phy-mtk-pcie.c
> @@ -0,0 +1,246 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 MediaTek Inc.
> + * Author: Jianjun Wang <jianjun.wang@...iatek.com>
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/compiler_types.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include "phy-mtk-io.h"
> +
> +#define PEXTP_ANA_GLB_00_REG 0x9000
> +#define PEXTP_ANA_LN0_TRX_REG 0xa000
> +#define PEXTP_ANA_TX_OFFSET 0x04
> +#define PEXTP_ANA_RX_OFFSET 0x3c
> +#define PEXTP_ANA_LANE_OFFSET 0x100
> +
> +/* PEXTP_GLB_00_REG[28:24] Internal Resistor Selection of TX Bias Current */
> +#define EFUSE_GLB_INTR_SEL GENMASK(28, 24)
> +#define EFUSE_GLB_INTR_VAL(x) ((0x1f & (x)) << 24)
> +
> +/* PEXTP_ANA_LN_RX_REG[3:0] RX impedance selection */
> +#define EFUSE_LN_RX_SEL GENMASK(3, 0)
> +#define EFUSE_LN_RX_VAL(x) (0xf & (x))
> +
> +/* PEXTP_ANA_LN_TX_REG[5:2] TX PMOS impedance selection */
> +#define EFUSE_LN_TX_PMOS_SEL GENMASK(5, 2)
> +#define EFUSE_LN_TX_PMOS_VAL(x) ((0xf & (x)) << 2)
> +
> +/* PEXTP_ANA_LN_TX_REG[11:8] TX NMOS impedance selection */
> +#define EFUSE_LN_TX_NMOS_SEL GENMASK(11, 8)
> +#define EFUSE_LN_TX_NMOS_VAL(x) ((0xf & (x)) << 8)
> +
> +/* Efuse data for each lane */
> +struct mtk_pcie_lane_efuse {
> + u32 tx_pmos;
> + u32 tx_nmos;
> + u32 rx_data;
> + bool lane_efuse_supported;
> +};
> +
> +struct mtk_pcie_phy {
> + struct device *dev;
> + struct phy *phy;
> + void __iomem *sif_base;
> +
> + /*
> + * Support software efuse initialization,
> + * currently we only support 2 lane in maximum.
> + */
> + bool sw_efuse_supported;
> + u32 efuse_glb_intr;
> + struct mtk_pcie_lane_efuse efuse[2];
> +};
> +
> +static void mtk_pcie_efuse_set_lane(struct mtk_pcie_phy *pcie_phy,
> + unsigned int lane)
> +{
> + struct mtk_pcie_lane_efuse *data;
> + void __iomem *addr;
> +
> + if (lane >= ARRAY_SIZE(pcie_phy->efuse)) {
> + dev_err(pcie_phy->dev,
> + "Requested lane number %d exceeds maximum %ld\n",
> + lane, ARRAY_SIZE(pcie_phy->efuse) - 1);
> + return;
> + }
> +
> + data = &pcie_phy->efuse[lane];
> + if (!data->lane_efuse_supported)
> + return;
> +
> + addr = pcie_phy->sif_base + PEXTP_ANA_LN0_TRX_REG +
> + lane * PEXTP_ANA_LANE_OFFSET;
> +
> + mtk_phy_update_bits(addr + PEXTP_ANA_TX_OFFSET, EFUSE_LN_TX_PMOS_SEL,
> + EFUSE_LN_TX_PMOS_VAL(data->tx_pmos));
> +
> + mtk_phy_update_bits(addr + PEXTP_ANA_TX_OFFSET, EFUSE_LN_TX_NMOS_SEL,
> + EFUSE_LN_TX_NMOS_VAL(data->tx_nmos));
> +
> + mtk_phy_update_bits(addr + PEXTP_ANA_RX_OFFSET, EFUSE_LN_RX_SEL,
> + EFUSE_LN_RX_VAL(data->rx_data));
> +}
> +
> +/**
> + * mtk_pcie_phy_init() - Initialize the phy
> + * @phy: the phy to be initialized
> + *
> + * Initialize the phy by setting the efuse data.
> + * The hardware settings will be reset during suspend, it should be
> + * reinitialized when the consumer calls phy_init() again on resume.
> + */
> +static int mtk_pcie_phy_init(struct phy *phy)
> +{
> + struct mtk_pcie_phy *pcie_phy = phy_get_drvdata(phy);
> +
> + if (!pcie_phy->sw_efuse_supported)
> + return 0;
> +
> + /* Set global data */
> + mtk_phy_update_bits(pcie_phy->sif_base + PEXTP_ANA_GLB_00_REG,
> + EFUSE_GLB_INTR_SEL,
> + EFUSE_GLB_INTR_VAL(pcie_phy->efuse_glb_intr));
> +
> + mtk_pcie_efuse_set_lane(pcie_phy, 0);
> +
> + mtk_pcie_efuse_set_lane(pcie_phy, 1);
> +
> + return 0;
> +}
> +
> +static const struct phy_ops mtk_pcie_phy_ops = {
> + .init = mtk_pcie_phy_init,
> + .owner = THIS_MODULE,
> +};
> +
> +static int mtk_pcie_efuse_read_for_lane(struct mtk_pcie_phy *pcie_phy,
> + unsigned int lane)
> +{
> + struct device *dev = pcie_phy->dev;
> + struct mtk_pcie_lane_efuse *data;
> + char efuse_id[15];
> + int ret;
> +
> + if (lane >= ARRAY_SIZE(pcie_phy->efuse))
> + return dev_err_probe(pcie_phy->dev, -EINVAL,
> + "Requested lane number %d exceeds maximum %ld\n",
> + lane, ARRAY_SIZE(pcie_phy->efuse) - 1);
> +
> + data = &pcie_phy->efuse[lane];
> +
> + snprintf(efuse_id, sizeof(efuse_id), "tx_ln%d_pmos", lane);
> + ret = nvmem_cell_read_variable_le_u32(dev, efuse_id, &data->tx_pmos);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to read %s\n", efuse_id);
> +
> + snprintf(efuse_id, sizeof(efuse_id), "tx_ln%d_nmos", lane);
> + ret = nvmem_cell_read_variable_le_u32(dev, efuse_id, &data->tx_nmos);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to read %s\n", efuse_id);
> +
> + snprintf(efuse_id, sizeof(efuse_id), "rx_ln%d", lane);
> + ret = nvmem_cell_read_variable_le_u32(dev, efuse_id, &data->rx_data);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to read %s\n", efuse_id);
> +
> + if (!(data->tx_pmos || data->tx_nmos || data->rx_data))
> + return dev_err_probe(dev, -EINVAL,
> + "No efuse data found for lane%d, but dts enable it\n",
> + lane);
> +
> + data->lane_efuse_supported = true;
> +
> + return 0;
> +}
> +
> +static int mtk_pcie_read_efuse(struct mtk_pcie_phy *pcie_phy)
> +{
> + struct device *dev = pcie_phy->dev;
> + bool nvmem_enabled;
> + int ret;
> +
> + nvmem_enabled = device_property_read_bool(dev, "nvmem-cells");
> + if (!nvmem_enabled)
> + return -ENODEV;
> +
> + ret = nvmem_cell_read_variable_le_u32(dev, "glb_intr",
> + &pcie_phy->efuse_glb_intr);
> + if (ret)
> + return dev_err_probe(dev, ret, "Failed to read glb_intr\n");
> +
> + pcie_phy->sw_efuse_supported = true;
> +
> + ret = mtk_pcie_efuse_read_for_lane(pcie_phy, 0);
> + if (ret)
> + return ret;
> +
> + ret = mtk_pcie_efuse_read_for_lane(pcie_phy, 1);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int mtk_pcie_phy_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct phy_provider *provider;
> + struct mtk_pcie_phy *pcie_phy;
> +
> + pcie_phy = devm_kzalloc(dev, sizeof(*pcie_phy), GFP_KERNEL);
> + if (!pcie_phy)
> + return -ENOMEM;
> +
> + pcie_phy->dev = dev;
> +
> + pcie_phy->sif_base = devm_platform_ioremap_resource_byname(pdev, "sif");
> + if (IS_ERR(pcie_phy->sif_base))
> + return dev_err_probe(dev, PTR_ERR(pcie_phy->sif_base),
> + "Failed to map phy-sif base\n");
> +
> + pcie_phy->phy = devm_phy_create(dev, dev->of_node, &mtk_pcie_phy_ops);
> + if (IS_ERR(pcie_phy->phy))
> + return dev_err_probe(dev, PTR_ERR(pcie_phy->phy),
> + "Failed to create PCIe phy\n");
> +
> + /*
> + * Failed to read the efuse data is not a fatal problem,
> + * ignore the failure and keep going.
> + */
> + mtk_pcie_read_efuse(pcie_phy);
You need to check the return value for -EPROBE_DEFER to defer probing.
> +
> + phy_set_drvdata(pcie_phy->phy, pcie_phy);
> +
> + provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> + if (IS_ERR(provider))
> + return dev_err_probe(dev, PTR_ERR(provider),
> + "PCIe phy probe failed\n");
> +
> + return 0;
> +}
> +
> +static const struct of_device_id mtk_pcie_phy_of_match[] = {
> + { .compatible = "mediatek,mt8195-pcie-phy" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, mtk_pcie_phy_of_match);
> +
> +static struct platform_driver mtk_pcie_phy_driver = {
> + .probe = mtk_pcie_phy_probe,
> + .driver = {
> + .name = "mtk-pcie-phy",
> + .of_match_table = mtk_pcie_phy_of_match,
> + },
> +};
> +module_platform_driver(mtk_pcie_phy_driver);
> +
> +MODULE_DESCRIPTION("MediaTek PCIe PHY driver");
> +MODULE_AUTHOR("Jianjun Wang <jianjun.wang@...iatek.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.18.0
>
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