drivers/phy/rockchip/phy-rockchip-emmc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Rockchip emmc PHY driver
   4  *
   5  * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com>
   6  * Copyright (C) 2016 ROCKCHIP, Inc.
   7  */
   8
   9 #include <linux/clk.h>
  10 #include <linux/delay.h>
  11 #include <linux/mfd/syscon.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15 #include <linux/phy/phy.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/regmap.h>
  18
  19 /*
  20  * The higher 16-bit of this register is used for write protection
  21  * only if BIT(x + 16) set to 1 the BIT(x) can be written.
  22  */
  23 #define HIWORD_UPDATE(val, mask, shift) \
  24                 ((val) << (shift) | (mask) << ((shift) + 16))
  25
  26 /* Register definition */
  27 #define GRF_EMMCPHY_CON0                0x0
  28 #define GRF_EMMCPHY_CON1                0x4
  29 #define GRF_EMMCPHY_CON2                0x8
  30 #define GRF_EMMCPHY_CON3                0xc
  31 #define GRF_EMMCPHY_CON4                0x10
  32 #define GRF_EMMCPHY_CON5                0x14
  33 #define GRF_EMMCPHY_CON6                0x18
  34 #define GRF_EMMCPHY_STATUS              0x20
  35
  36 #define PHYCTRL_PDB_MASK                0x1
  37 #define PHYCTRL_PDB_SHIFT               0x0
  38 #define PHYCTRL_PDB_PWR_ON              0x1
  39 #define PHYCTRL_PDB_PWR_OFF             0x0
  40 #define PHYCTRL_ENDLL_MASK              0x1
  41 #define PHYCTRL_ENDLL_SHIFT             0x1
  42 #define PHYCTRL_ENDLL_ENABLE            0x1
  43 #define PHYCTRL_ENDLL_DISABLE           0x0
  44 #define PHYCTRL_CALDONE_MASK            0x1
  45 #define PHYCTRL_CALDONE_SHIFT           0x6
  46 #define PHYCTRL_CALDONE_DONE            0x1
  47 #define PHYCTRL_CALDONE_GOING           0x0
  48 #define PHYCTRL_DLLRDY_MASK             0x1
  49 #define PHYCTRL_DLLRDY_SHIFT            0x5
  50 #define PHYCTRL_DLLRDY_DONE             0x1
  51 #define PHYCTRL_DLLRDY_GOING            0x0
  52 #define PHYCTRL_FREQSEL_200M            0x0
  53 #define PHYCTRL_FREQSEL_50M             0x1
  54 #define PHYCTRL_FREQSEL_100M            0x2
  55 #define PHYCTRL_FREQSEL_150M            0x3
  56 #define PHYCTRL_FREQSEL_MASK            0x3
  57 #define PHYCTRL_FREQSEL_SHIFT           0xc
  58 #define PHYCTRL_DR_MASK                 0x7
  59 #define PHYCTRL_DR_SHIFT                0x4
  60 #define PHYCTRL_DR_50OHM                0x0
  61 #define PHYCTRL_DR_33OHM                0x1
  62 #define PHYCTRL_DR_66OHM                0x2
  63 #define PHYCTRL_DR_100OHM               0x3
  64 #define PHYCTRL_DR_40OHM                0x4
  65 #define PHYCTRL_OTAPDLYENA              0x1
  66 #define PHYCTRL_OTAPDLYENA_MASK         0x1
  67 #define PHYCTRL_OTAPDLYENA_SHIFT        0xb
  68 #define PHYCTRL_OTAPDLYSEL_MASK         0xf
  69 #define PHYCTRL_OTAPDLYSEL_SHIFT        0x7
  70
  71 #define PHYCTRL_IS_CALDONE(x) \
  72         ((((x) >> PHYCTRL_CALDONE_SHIFT) & \
  73           PHYCTRL_CALDONE_MASK) == PHYCTRL_CALDONE_DONE)
  74 #define PHYCTRL_IS_DLLRDY(x) \
  75         ((((x) >> PHYCTRL_DLLRDY_SHIFT) & \
  76           PHYCTRL_DLLRDY_MASK) == PHYCTRL_DLLRDY_DONE)
  77
  78 struct rockchip_emmc_phy {
  79         unsigned int    reg_offset;
  80         struct regmap   *reg_base;
  81         struct clk      *emmcclk;
  82         unsigned int drive_impedance;
  83 };
  84
  85 static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
  86 {
  87         struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
  88         unsigned int caldone;
  89         unsigned int dllrdy;
  90         unsigned int freqsel = PHYCTRL_FREQSEL_200M;
  91         unsigned long rate;
  92         int ret;
  93
  94         /*
  95          * Keep phyctrl_pdb and phyctrl_endll low to allow
  96          * initialization of CALIO state M/C DFFs
  97          */
  98         regmap_write(rk_phy->reg_base,
  99                      rk_phy->reg_offset + GRF_EMMCPHY_CON6,
 100                      HIWORD_UPDATE(PHYCTRL_PDB_PWR_OFF,
 101                                    PHYCTRL_PDB_MASK,
 102                                    PHYCTRL_PDB_SHIFT));
 103         regmap_write(rk_phy->reg_base,
 104                      rk_phy->reg_offset + GRF_EMMCPHY_CON6,
 105                      HIWORD_UPDATE(PHYCTRL_ENDLL_DISABLE,
 106                                    PHYCTRL_ENDLL_MASK,
 107                                    PHYCTRL_ENDLL_SHIFT));
 108
 109         /* Already finish power_off above */
 110         if (on_off == PHYCTRL_PDB_PWR_OFF)
 111                 return 0;
 112
 113         rate = clk_get_rate(rk_phy->emmcclk);
 114
 115         if (rate != 0) {
 116                 unsigned long ideal_rate;
 117                 unsigned long diff;
 118
 119                 switch (rate) {
 120                 case 1 ... 74999999:
 121                         ideal_rate = 50000000;
 122                         freqsel = PHYCTRL_FREQSEL_50M;
 123                         break;
 124                 case 75000000 ... 124999999:
 125                         ideal_rate = 100000000;
 126                         freqsel = PHYCTRL_FREQSEL_100M;
 127                         break;
 128                 case 125000000 ... 174999999:
 129                         ideal_rate = 150000000;
 130                         freqsel = PHYCTRL_FREQSEL_150M;
 131                         break;
 132                 default:
 133                         ideal_rate = 200000000;
 134                         break;
 135                 }
 136
 137                 diff = (rate > ideal_rate) ?
 138                         rate - ideal_rate : ideal_rate - rate;
 139
 140                 /*
 141                  * In order for tuning delays to be accurate we need to be
 142                  * pretty spot on for the DLL range, so warn if we're too
 143                  * far off.  Also warn if we're above the 200 MHz max.  Don't
 144                  * warn for really slow rates since we won't be tuning then.
 145                  */
 146                 if ((rate > 50000000 && diff > 15000000) || (rate > 200000000))
 147                         dev_warn(&phy->dev, "Unsupported rate: %lu\n", rate);
 148         }
 149
 150         /*
 151          * According to the user manual, calpad calibration
 152          * cycle takes more than 2us without the minimal recommended
 153          * value, so we may need a little margin here
 154          */
 155         udelay(3);
 156         regmap_write(rk_phy->reg_base,
 157                      rk_phy->reg_offset + GRF_EMMCPHY_CON6,
 158                      HIWORD_UPDATE(PHYCTRL_PDB_PWR_ON,
 159                                    PHYCTRL_PDB_MASK,
 160                                    PHYCTRL_PDB_SHIFT));
 161
 162         /*
 163          * According to the user manual, it asks driver to wait 5us for
 164          * calpad busy trimming. However it is documented that this value is
 165          * PVT(A.K.A process,voltage and temperature) relevant, so some
 166          * failure cases are found which indicates we should be more tolerant
 167          * to calpad busy trimming.
 168          */
 169         ret = regmap_read_poll_timeout(rk_phy->reg_base,
 170                                        rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
 171                                        caldone, PHYCTRL_IS_CALDONE(caldone),
 172                                        0, 50);
 173         if (ret) {
 174                 pr_err("%s: caldone failed, ret=%d\n", __func__, ret);
 175                 return ret;
 176         }
 177
 178         /* Set the frequency of the DLL operation */
 179         regmap_write(rk_phy->reg_base,
 180                      rk_phy->reg_offset + GRF_EMMCPHY_CON0,
 181                      HIWORD_UPDATE(freqsel, PHYCTRL_FREQSEL_MASK,
 182                                    PHYCTRL_FREQSEL_SHIFT));
 183
 184         /* Turn on the DLL */
 185         regmap_write(rk_phy->reg_base,
 186                      rk_phy->reg_offset + GRF_EMMCPHY_CON6,
 187                      HIWORD_UPDATE(PHYCTRL_ENDLL_ENABLE,
 188                                    PHYCTRL_ENDLL_MASK,
 189                                    PHYCTRL_ENDLL_SHIFT));
 190
 191         /*
 192          * We turned on the DLL even though the rate was 0 because we the
 193          * clock might be turned on later.  ...but we can't wait for the DLL
 194          * to lock when the rate is 0 because it will never lock with no
 195          * input clock.
 196          *
 197          * Technically we should be checking the lock later when the clock
 198          * is turned on, but for now we won't.
 199          */
 200         if (rate == 0)
 201                 return 0;
 202
 203         /*
 204          * After enabling analog DLL circuits docs say that we need 10.2 us if
 205          * our source clock is at 50 MHz and that lock time scales linearly
 206          * with clock speed.  If we are powering on the PHY and the card clock
 207          * is super slow (like 100 kHZ) this could take as long as 5.1 ms as
 208          * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
 209          * Hopefully we won't be running at 100 kHz, but we should still make
 210          * sure we wait long enough.
 211          *
 212          * NOTE: There appear to be corner cases where the DLL seems to take
 213          * extra long to lock for reasons that aren't understood.  In some
 214          * extreme cases we've seen it take up to over 10ms (!).  We'll be
 215          * generous and give it 50ms.
 216          */
 217         ret = regmap_read_poll_timeout(rk_phy->reg_base,
 218                                        rk_phy->reg_offset + GRF_EMMCPHY_STATUS,
 219                                        dllrdy, PHYCTRL_IS_DLLRDY(dllrdy),
 220                                        0, 50 * USEC_PER_MSEC);
 221         if (ret) {
 222                 pr_err("%s: dllrdy failed. ret=%d\n", __func__, ret);
 223                 return ret;
 224         }
 225
 226         return 0;
 227 }
 228
 229 static int rockchip_emmc_phy_init(struct phy *phy)
 230 {
 231         struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
 232         int ret = 0;
 233
 234         /*
 235          * We purposely get the clock here and not in probe to avoid the
 236          * circular dependency problem.  We expect:
 237          * - PHY driver to probe
 238          * - SDHCI driver to start probe
 239          * - SDHCI driver to register it's clock
 240          * - SDHCI driver to get the PHY
 241          * - SDHCI driver to init the PHY
 242          *
 243          * The clock is optional, so upon any error we just set to NULL.
 244          *
 245          * NOTE: we don't do anything special for EPROBE_DEFER here.  Given the
 246          * above expected use case, EPROBE_DEFER isn't sensible to expect, so
 247          * it's just like any other error.
 248          */
 249         rk_phy->emmcclk = clk_get(&phy->dev, "emmcclk");
 250         if (IS_ERR(rk_phy->emmcclk)) {
 251                 dev_dbg(&phy->dev, "Error getting emmcclk: %d\n", ret);
 252                 rk_phy->emmcclk = NULL;
 253         }
 254
 255         return ret;
 256 }
 257
 258 static int rockchip_emmc_phy_exit(struct phy *phy)
 259 {
 260         struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
 261
 262         clk_put(rk_phy->emmcclk);
 263
 264         return 0;
 265 }
 266
 267 static int rockchip_emmc_phy_power_off(struct phy *phy)
 268 {
 269         /* Power down emmc phy analog blocks */
 270         return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_OFF);
 271 }
 272
 273 static int rockchip_emmc_phy_power_on(struct phy *phy)
 274 {
 275         struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);
 276
 277         /* Drive impedance: from DTS */
 278         regmap_write(rk_phy->reg_base,
 279                      rk_phy->reg_offset + GRF_EMMCPHY_CON6,
 280                      HIWORD_UPDATE(rk_phy->drive_impedance,
 281                                    PHYCTRL_DR_MASK,
 282                                    PHYCTRL_DR_SHIFT));
 283
 284         /* Output tap delay: enable */
 285         regmap_write(rk_phy->reg_base,
 286                      rk_phy->reg_offset + GRF_EMMCPHY_CON0,
 287                      HIWORD_UPDATE(PHYCTRL_OTAPDLYENA,
 288                                    PHYCTRL_OTAPDLYENA_MASK,
 289                                    PHYCTRL_OTAPDLYENA_SHIFT));
 290
 291         /* Output tap delay */
 292         regmap_write(rk_phy->reg_base,
 293                      rk_phy->reg_offset + GRF_EMMCPHY_CON0,
 294                      HIWORD_UPDATE(4,
 295                                    PHYCTRL_OTAPDLYSEL_MASK,
 296                                    PHYCTRL_OTAPDLYSEL_SHIFT));
 297
 298         /* Power up emmc phy analog blocks */
 299         return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_ON);
 300 }
 301
 302 static const struct phy_ops ops = {
 303         .init           = rockchip_emmc_phy_init,
 304         .exit           = rockchip_emmc_phy_exit,
 305         .power_on       = rockchip_emmc_phy_power_on,
 306         .power_off      = rockchip_emmc_phy_power_off,
 307         .owner          = THIS_MODULE,
 308 };
 309
 310 static u32 convert_drive_impedance_ohm(struct platform_device *pdev, u32 dr_ohm)
 311 {
 312         switch (dr_ohm) {
 313         case 100:
 314                 return PHYCTRL_DR_100OHM;
 315         case 66:
 316                 return PHYCTRL_DR_66OHM;
 317         case 50:
 318                 return PHYCTRL_DR_50OHM;
 319         case 40:
 320                 return PHYCTRL_DR_40OHM;
 321         case 33:
 322                 return PHYCTRL_DR_33OHM;
 323         }
 324
 325         dev_warn(&pdev->dev, "Invalid value %u for drive-impedance-ohm.\n",
 326                  dr_ohm);
 327         return PHYCTRL_DR_50OHM;
 328 }
 329
 330 static int rockchip_emmc_phy_probe(struct platform_device *pdev)
 331 {
 332         struct device *dev = &pdev->dev;
 333         struct rockchip_emmc_phy *rk_phy;
 334         struct phy *generic_phy;
 335         struct phy_provider *phy_provider;
 336         struct regmap *grf;
 337         unsigned int reg_offset;
 338         u32 val;
 339
 340         if (!dev->parent || !dev->parent->of_node)
 341                 return -ENODEV;
 342
 343         grf = syscon_node_to_regmap(dev->parent->of_node);
 344         if (IS_ERR(grf)) {
 345                 dev_err(dev, "Missing rockchip,grf property\n");
 346                 return PTR_ERR(grf);
 347         }
 348
 349         rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL);
 350         if (!rk_phy)
 351                 return -ENOMEM;
 352
 353         if (of_property_read_u32(dev->of_node, "reg", &reg_offset)) {
 354                 dev_err(dev, "missing reg property in node %pOFn\n",
 355                         dev->of_node);
 356                 return -EINVAL;
 357         }
 358
 359         rk_phy->reg_offset = reg_offset;
 360         rk_phy->reg_base = grf;
 361         rk_phy->drive_impedance = PHYCTRL_DR_50OHM;
 362
 363         if (!of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val))
 364                 rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, val);
 365
 366         generic_phy = devm_phy_create(dev, dev->of_node, &ops);
 367         if (IS_ERR(generic_phy)) {
 368                 dev_err(dev, "failed to create PHY\n");
 369                 return PTR_ERR(generic_phy);
 370         }
 371
 372         phy_set_drvdata(generic_phy, rk_phy);
 373         phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 374
 375         return PTR_ERR_OR_ZERO(phy_provider);
 376 }
 377
 378 static const struct of_device_id rockchip_emmc_phy_dt_ids[] = {
 379         { .compatible = "rockchip,rk3399-emmc-phy" },
 380         {}
 381 };
 382
 383 MODULE_DEVICE_TABLE(of, rockchip_emmc_phy_dt_ids);
 384
 385 static struct platform_driver rockchip_emmc_driver = {
 386         .probe          = rockchip_emmc_phy_probe,
 387         .driver         = {
 388                 .name   = "rockchip-emmc-phy",
 389                 .of_match_table = rockchip_emmc_phy_dt_ids,
 390         },
 391 };
 392
 393 module_platform_driver(rockchip_emmc_driver);
 394
 395 MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>");
 396 MODULE_DESCRIPTION("Rockchip EMMC PHY driver");
 397 MODULE_LICENSE("GPL v2");