linux/drivers/phy/intel/phy-intel-keembay-usb.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Intel Keem Bay USB PHY driver
   4 * Copyright (C) 2020 Intel Corporation
   5 */
   6
   7#include <linux/bitfield.h>
   8#include <linux/bits.h>
   9#include <linux/clk.h>
  10#include <linux/delay.h>
  11#include <linux/mod_devicetable.h>
  12#include <linux/module.h>
  13#include <linux/phy/phy.h>
  14#include <linux/platform_device.h>
  15#include <linux/regmap.h>
  16
  17/* USS (USB Subsystem) clock control registers */
  18#define USS_CPR_CLK_EN          0x00
  19#define USS_CPR_CLK_SET         0x04
  20#define USS_CPR_CLK_CLR         0x08
  21#define USS_CPR_RST_EN          0x10
  22#define USS_CPR_RST_SET         0x14
  23#define USS_CPR_RST_CLR         0x18
  24
  25/* USS clock/reset bit fields */
  26#define USS_CPR_PHY_TST         BIT(6)
  27#define USS_CPR_LOW_JIT         BIT(5)
  28#define USS_CPR_CORE            BIT(4)
  29#define USS_CPR_SUSPEND         BIT(3)
  30#define USS_CPR_ALT_REF         BIT(2)
  31#define USS_CPR_REF             BIT(1)
  32#define USS_CPR_SYS             BIT(0)
  33#define USS_CPR_MASK            GENMASK(6, 0)
  34
  35/* USS APB slave registers */
  36#define USS_USB_CTRL_CFG0               0x10
  37#define  VCC_RESET_N_MASK               BIT(31)
  38
  39#define USS_USB_PHY_CFG0                0x30
  40#define  POR_MASK                       BIT(15)
  41#define  PHY_RESET_MASK                 BIT(14)
  42#define  PHY_REF_USE_PAD_MASK           BIT(5)
  43
  44#define USS_USB_PHY_CFG6                0x64
  45#define  PHY0_SRAM_EXT_LD_DONE_MASK     BIT(23)
  46
  47#define USS_USB_PARALLEL_IF_CTRL        0xa0
  48#define  USB_PHY_CR_PARA_SEL_MASK       BIT(2)
  49
  50#define USS_USB_TSET_SIGNALS_AND_GLOB   0xac
  51#define  USB_PHY_CR_PARA_CLK_EN_MASK    BIT(7)
  52
  53#define USS_USB_STATUS_REG              0xb8
  54#define  PHY0_SRAM_INIT_DONE_MASK       BIT(3)
  55
  56#define USS_USB_TIEOFFS_CONSTANTS_REG1  0xc0
  57#define  IDDQ_ENABLE_MASK               BIT(10)
  58
  59struct keembay_usb_phy {
  60        struct device *dev;
  61        struct regmap *regmap_cpr;
  62        struct regmap *regmap_slv;
  63};
  64
  65static const struct regmap_config keembay_regmap_config = {
  66        .reg_bits = 32,
  67        .val_bits = 32,
  68        .reg_stride = 4,
  69        .max_register = USS_USB_TIEOFFS_CONSTANTS_REG1,
  70};
  71
  72static int keembay_usb_clocks_on(struct keembay_usb_phy *priv)
  73{
  74        int ret;
  75
  76        ret = regmap_update_bits(priv->regmap_cpr, USS_CPR_CLK_SET,
  77                                 USS_CPR_MASK, USS_CPR_MASK);
  78        if (ret) {
  79                dev_err(priv->dev, "error clock set: %d\n", ret);
  80                return ret;
  81        }
  82
  83        ret = regmap_update_bits(priv->regmap_cpr, USS_CPR_RST_SET,
  84                                 USS_CPR_MASK, USS_CPR_MASK);
  85        if (ret) {
  86                dev_err(priv->dev, "error reset set: %d\n", ret);
  87                return ret;
  88        }
  89
  90        ret = regmap_update_bits(priv->regmap_slv,
  91                                 USS_USB_TIEOFFS_CONSTANTS_REG1,
  92                                 IDDQ_ENABLE_MASK,
  93                                 FIELD_PREP(IDDQ_ENABLE_MASK, 0));
  94        if (ret) {
  95                dev_err(priv->dev, "error iddq disable: %d\n", ret);
  96                return ret;
  97        }
  98
  99        /* Wait 30us to ensure all analog blocks are powered up. */
 100        usleep_range(30, 60);
 101
 102        ret = regmap_update_bits(priv->regmap_slv, USS_USB_PHY_CFG0,
 103                                 PHY_REF_USE_PAD_MASK,
 104                                 FIELD_PREP(PHY_REF_USE_PAD_MASK, 1));
 105        if (ret)
 106                dev_err(priv->dev, "error ref clock select: %d\n", ret);
 107
 108        return ret;
 109}
 110
 111static int keembay_usb_core_off(struct keembay_usb_phy *priv)
 112{
 113        int ret;
 114
 115        ret = regmap_update_bits(priv->regmap_slv, USS_USB_CTRL_CFG0,
 116                                 VCC_RESET_N_MASK,
 117                                 FIELD_PREP(VCC_RESET_N_MASK, 0));
 118        if (ret)
 119                dev_err(priv->dev, "error core reset: %d\n", ret);
 120
 121        return ret;
 122}
 123
 124static int keembay_usb_core_on(struct keembay_usb_phy *priv)
 125{
 126        int ret;
 127
 128        ret = regmap_update_bits(priv->regmap_slv, USS_USB_CTRL_CFG0,
 129                                 VCC_RESET_N_MASK,
 130                                 FIELD_PREP(VCC_RESET_N_MASK, 1));
 131        if (ret)
 132                dev_err(priv->dev, "error core on: %d\n", ret);
 133
 134        return ret;
 135}
 136
 137static int keembay_usb_phys_on(struct keembay_usb_phy *priv)
 138{
 139        int ret;
 140
 141        ret = regmap_update_bits(priv->regmap_slv, USS_USB_PHY_CFG0,
 142                                 POR_MASK | PHY_RESET_MASK,
 143                                 FIELD_PREP(POR_MASK | PHY_RESET_MASK, 0));
 144        if (ret)
 145                dev_err(priv->dev, "error phys on: %d\n", ret);
 146
 147        return ret;
 148}
 149
 150static int keembay_usb_phy_init(struct phy *phy)
 151{
 152        struct keembay_usb_phy *priv = phy_get_drvdata(phy);
 153        u32 val;
 154        int ret;
 155
 156        ret = keembay_usb_core_off(priv);
 157        if (ret)
 158                return ret;
 159
 160        /*
 161         * According to Keem Bay datasheet, wait minimum 20us after clock
 162         * enable before bringing PHYs out of reset.
 163         */
 164        usleep_range(20, 40);
 165
 166        ret = keembay_usb_phys_on(priv);
 167        if (ret)
 168                return ret;
 169
 170        ret = regmap_update_bits(priv->regmap_slv,
 171                                 USS_USB_TSET_SIGNALS_AND_GLOB,
 172                                 USB_PHY_CR_PARA_CLK_EN_MASK,
 173                                 FIELD_PREP(USB_PHY_CR_PARA_CLK_EN_MASK, 0));
 174        if (ret) {
 175                dev_err(priv->dev, "error cr clock disable: %d\n", ret);
 176                return ret;
 177        }
 178
 179        /*
 180         * According to Keem Bay datasheet, wait 2us after disabling the
 181         * clock into the USB 3.x parallel interface.
 182         */
 183        udelay(2);
 184
 185        ret = regmap_update_bits(priv->regmap_slv,
 186                                 USS_USB_PARALLEL_IF_CTRL,
 187                                 USB_PHY_CR_PARA_SEL_MASK,
 188                                 FIELD_PREP(USB_PHY_CR_PARA_SEL_MASK, 1));
 189        if (ret) {
 190                dev_err(priv->dev, "error cr select: %d\n", ret);
 191                return ret;
 192        }
 193
 194        ret = regmap_update_bits(priv->regmap_slv,
 195                                 USS_USB_TSET_SIGNALS_AND_GLOB,
 196                                 USB_PHY_CR_PARA_CLK_EN_MASK,
 197                                 FIELD_PREP(USB_PHY_CR_PARA_CLK_EN_MASK, 1));
 198        if (ret) {
 199                dev_err(priv->dev, "error cr clock enable: %d\n", ret);
 200                return ret;
 201        }
 202
 203        ret = regmap_read_poll_timeout(priv->regmap_slv, USS_USB_STATUS_REG,
 204                                       val, val & PHY0_SRAM_INIT_DONE_MASK,
 205                                       USEC_PER_MSEC, 10 * USEC_PER_MSEC);
 206        if (ret) {
 207                dev_err(priv->dev, "SRAM init not done: %d\n", ret);
 208                return ret;
 209        }
 210
 211        ret = regmap_update_bits(priv->regmap_slv, USS_USB_PHY_CFG6,
 212                                 PHY0_SRAM_EXT_LD_DONE_MASK,
 213                                 FIELD_PREP(PHY0_SRAM_EXT_LD_DONE_MASK, 1));
 214        if (ret) {
 215                dev_err(priv->dev, "error SRAM init done set: %d\n", ret);
 216                return ret;
 217        }
 218
 219        /*
 220         * According to Keem Bay datasheet, wait 20us after setting the
 221         * SRAM load done bit, before releasing the controller reset.
 222         */
 223        usleep_range(20, 40);
 224
 225        return keembay_usb_core_on(priv);
 226}
 227
 228static const struct phy_ops ops = {
 229        .init           = keembay_usb_phy_init,
 230        .owner          = THIS_MODULE,
 231};
 232
 233static int keembay_usb_phy_probe(struct platform_device *pdev)
 234{
 235        struct device *dev = &pdev->dev;
 236        struct keembay_usb_phy *priv;
 237        struct phy *generic_phy;
 238        struct phy_provider *phy_provider;
 239        void __iomem *base;
 240        int ret;
 241
 242        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 243        if (!priv)
 244                return -ENOMEM;
 245
 246        base = devm_platform_ioremap_resource_byname(pdev, "cpr-apb-base");
 247        if (IS_ERR(base))
 248                return PTR_ERR(base);
 249
 250        priv->regmap_cpr = devm_regmap_init_mmio(dev, base,
 251                                                 &keembay_regmap_config);
 252        if (IS_ERR(priv->regmap_cpr))
 253                return PTR_ERR(priv->regmap_cpr);
 254
 255        base = devm_platform_ioremap_resource_byname(pdev, "slv-apb-base");
 256        if (IS_ERR(base))
 257                return PTR_ERR(base);
 258
 259        priv->regmap_slv = devm_regmap_init_mmio(dev, base,
 260                                                 &keembay_regmap_config);
 261        if (IS_ERR(priv->regmap_slv))
 262                return PTR_ERR(priv->regmap_slv);
 263
 264        generic_phy = devm_phy_create(dev, dev->of_node, &ops);
 265        if (IS_ERR(generic_phy))
 266                return dev_err_probe(dev, PTR_ERR(generic_phy),
 267                                     "failed to create PHY\n");
 268
 269        phy_set_drvdata(generic_phy, priv);
 270        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 271        if (IS_ERR(phy_provider))
 272                return dev_err_probe(dev, PTR_ERR(phy_provider),
 273                                     "failed to register phy provider\n");
 274
 275        /* Setup USB subsystem clocks */
 276        ret = keembay_usb_clocks_on(priv);
 277        if (ret)
 278                return ret;
 279
 280        /* and turn on the DWC3 core, prior to DWC3 driver init. */
 281        return keembay_usb_core_on(priv);
 282}
 283
 284static const struct of_device_id keembay_usb_phy_dt_ids[] = {
 285        { .compatible = "intel,keembay-usb-phy" },
 286        {}
 287};
 288MODULE_DEVICE_TABLE(of, keembay_usb_phy_dt_ids);
 289
 290static struct platform_driver keembay_usb_phy_driver = {
 291        .probe          = keembay_usb_phy_probe,
 292        .driver         = {
 293                .name   = "keembay-usb-phy",
 294                .of_match_table = keembay_usb_phy_dt_ids,
 295        },
 296};
 297module_platform_driver(keembay_usb_phy_driver);
 298
 299MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>");
 300MODULE_DESCRIPTION("Intel Keem Bay USB PHY driver");
 301MODULE_LICENSE("GPL v2");
 302