1 /* 2 * Rockchip emmc PHY driver 3 * 4 * Copyright (C) 2016 Shawn Lin <shawn.lin@rock-chips.com> 5 * Copyright (C) 2016 ROCKCHIP, Inc. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/clk.h> 18 #include <linux/delay.h> 19 #include <linux/mfd/syscon.h> 20 #include <linux/module.h> 21 #include <linux/of.h> 22 #include <linux/of_address.h> 23 #include <linux/phy/phy.h> 24 #include <linux/platform_device.h> 25 #include <linux/regmap.h> 26 27 /* 28 * The higher 16-bit of this register is used for write protection 29 * only if BIT(x + 16) set to 1 the BIT(x) can be written. 30 */ 31 #define HIWORD_UPDATE(val, mask, shift) \ 32 ((val) << (shift) | (mask) << ((shift) + 16)) 33 34 /* Register definition */ 35 #define GRF_EMMCPHY_CON0 0x0 36 #define GRF_EMMCPHY_CON1 0x4 37 #define GRF_EMMCPHY_CON2 0x8 38 #define GRF_EMMCPHY_CON3 0xc 39 #define GRF_EMMCPHY_CON4 0x10 40 #define GRF_EMMCPHY_CON5 0x14 41 #define GRF_EMMCPHY_CON6 0x18 42 #define GRF_EMMCPHY_STATUS 0x20 43 44 #define PHYCTRL_PDB_MASK 0x1 45 #define PHYCTRL_PDB_SHIFT 0x0 46 #define PHYCTRL_PDB_PWR_ON 0x1 47 #define PHYCTRL_PDB_PWR_OFF 0x0 48 #define PHYCTRL_ENDLL_MASK 0x1 49 #define PHYCTRL_ENDLL_SHIFT 0x1 50 #define PHYCTRL_ENDLL_ENABLE 0x1 51 #define PHYCTRL_ENDLL_DISABLE 0x0 52 #define PHYCTRL_CALDONE_MASK 0x1 53 #define PHYCTRL_CALDONE_SHIFT 0x6 54 #define PHYCTRL_CALDONE_DONE 0x1 55 #define PHYCTRL_CALDONE_GOING 0x0 56 #define PHYCTRL_DLLRDY_MASK 0x1 57 #define PHYCTRL_DLLRDY_SHIFT 0x5 58 #define PHYCTRL_DLLRDY_DONE 0x1 59 #define PHYCTRL_DLLRDY_GOING 0x0 60 #define PHYCTRL_FREQSEL_200M 0x0 61 #define PHYCTRL_FREQSEL_50M 0x1 62 #define PHYCTRL_FREQSEL_100M 0x2 63 #define PHYCTRL_FREQSEL_150M 0x3 64 #define PHYCTRL_FREQSEL_MASK 0x3 65 #define PHYCTRL_FREQSEL_SHIFT 0xc 66 #define PHYCTRL_DR_MASK 0x7 67 #define PHYCTRL_DR_SHIFT 0x4 68 #define PHYCTRL_DR_50OHM 0x0 69 #define PHYCTRL_DR_33OHM 0x1 70 #define PHYCTRL_DR_66OHM 0x2 71 #define PHYCTRL_DR_100OHM 0x3 72 #define PHYCTRL_DR_40OHM 0x4 73 #define PHYCTRL_OTAPDLYENA 0x1 74 #define PHYCTRL_OTAPDLYENA_MASK 0x1 75 #define PHYCTRL_OTAPDLYENA_SHIFT 0xb 76 #define PHYCTRL_OTAPDLYSEL_MASK 0xf 77 #define PHYCTRL_OTAPDLYSEL_SHIFT 0x7 78 79 #define PHYCTRL_IS_CALDONE(x) \ 80 ((((x) >> PHYCTRL_CALDONE_SHIFT) & \ 81 PHYCTRL_CALDONE_MASK) == PHYCTRL_CALDONE_DONE) 82 #define PHYCTRL_IS_DLLRDY(x) \ 83 ((((x) >> PHYCTRL_DLLRDY_SHIFT) & \ 84 PHYCTRL_DLLRDY_MASK) == PHYCTRL_DLLRDY_DONE) 85 86 struct rockchip_emmc_phy { 87 unsigned int reg_offset; 88 struct regmap *reg_base; 89 struct clk *emmcclk; 90 unsigned int drive_impedance; 91 }; 92 93 static int rockchip_emmc_phy_power(struct phy *phy, bool on_off) 94 { 95 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy); 96 unsigned int caldone; 97 unsigned int dllrdy; 98 unsigned int freqsel = PHYCTRL_FREQSEL_200M; 99 unsigned long rate; 100 int ret; 101 102 /* 103 * Keep phyctrl_pdb and phyctrl_endll low to allow 104 * initialization of CALIO state M/C DFFs 105 */ 106 regmap_write(rk_phy->reg_base, 107 rk_phy->reg_offset + GRF_EMMCPHY_CON6, 108 HIWORD_UPDATE(PHYCTRL_PDB_PWR_OFF, 109 PHYCTRL_PDB_MASK, 110 PHYCTRL_PDB_SHIFT)); 111 regmap_write(rk_phy->reg_base, 112 rk_phy->reg_offset + GRF_EMMCPHY_CON6, 113 HIWORD_UPDATE(PHYCTRL_ENDLL_DISABLE, 114 PHYCTRL_ENDLL_MASK, 115 PHYCTRL_ENDLL_SHIFT)); 116 117 /* Already finish power_off above */ 118 if (on_off == PHYCTRL_PDB_PWR_OFF) 119 return 0; 120 121 rate = clk_get_rate(rk_phy->emmcclk); 122 123 if (rate != 0) { 124 unsigned long ideal_rate; 125 unsigned long diff; 126 127 switch (rate) { 128 case 1 ... 74999999: 129 ideal_rate = 50000000; 130 freqsel = PHYCTRL_FREQSEL_50M; 131 break; 132 case 75000000 ... 124999999: 133 ideal_rate = 100000000; 134 freqsel = PHYCTRL_FREQSEL_100M; 135 break; 136 case 125000000 ... 174999999: 137 ideal_rate = 150000000; 138 freqsel = PHYCTRL_FREQSEL_150M; 139 break; 140 default: 141 ideal_rate = 200000000; 142 break; 143 } 144 145 diff = (rate > ideal_rate) ? 146 rate - ideal_rate : ideal_rate - rate; 147 148 /* 149 * In order for tuning delays to be accurate we need to be 150 * pretty spot on for the DLL range, so warn if we're too 151 * far off. Also warn if we're above the 200 MHz max. Don't 152 * warn for really slow rates since we won't be tuning then. 153 */ 154 if ((rate > 50000000 && diff > 15000000) || (rate > 200000000)) 155 dev_warn(&phy->dev, "Unsupported rate: %lu\n", rate); 156 } 157 158 /* 159 * According to the user manual, calpad calibration 160 * cycle takes more than 2us without the minimal recommended 161 * value, so we may need a little margin here 162 */ 163 udelay(3); 164 regmap_write(rk_phy->reg_base, 165 rk_phy->reg_offset + GRF_EMMCPHY_CON6, 166 HIWORD_UPDATE(PHYCTRL_PDB_PWR_ON, 167 PHYCTRL_PDB_MASK, 168 PHYCTRL_PDB_SHIFT)); 169 170 /* 171 * According to the user manual, it asks driver to wait 5us for 172 * calpad busy trimming. However it is documented that this value is 173 * PVT(A.K.A process,voltage and temperature) relevant, so some 174 * failure cases are found which indicates we should be more tolerant 175 * to calpad busy trimming. 176 */ 177 ret = regmap_read_poll_timeout(rk_phy->reg_base, 178 rk_phy->reg_offset + GRF_EMMCPHY_STATUS, 179 caldone, PHYCTRL_IS_CALDONE(caldone), 180 0, 50); 181 if (ret) { 182 pr_err("%s: caldone failed, ret=%d\n", __func__, ret); 183 return ret; 184 } 185 186 /* Set the frequency of the DLL operation */ 187 regmap_write(rk_phy->reg_base, 188 rk_phy->reg_offset + GRF_EMMCPHY_CON0, 189 HIWORD_UPDATE(freqsel, PHYCTRL_FREQSEL_MASK, 190 PHYCTRL_FREQSEL_SHIFT)); 191 192 /* Turn on the DLL */ 193 regmap_write(rk_phy->reg_base, 194 rk_phy->reg_offset + GRF_EMMCPHY_CON6, 195 HIWORD_UPDATE(PHYCTRL_ENDLL_ENABLE, 196 PHYCTRL_ENDLL_MASK, 197 PHYCTRL_ENDLL_SHIFT)); 198 199 /* 200 * We turned on the DLL even though the rate was 0 because we the 201 * clock might be turned on later. ...but we can't wait for the DLL 202 * to lock when the rate is 0 because it will never lock with no 203 * input clock. 204 * 205 * Technically we should be checking the lock later when the clock 206 * is turned on, but for now we won't. 207 */ 208 if (rate == 0) 209 return 0; 210 211 /* 212 * After enabling analog DLL circuits docs say that we need 10.2 us if 213 * our source clock is at 50 MHz and that lock time scales linearly 214 * with clock speed. If we are powering on the PHY and the card clock 215 * is super slow (like 100 kHZ) this could take as long as 5.1 ms as 216 * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms 217 * Hopefully we won't be running at 100 kHz, but we should still make 218 * sure we wait long enough. 219 * 220 * NOTE: There appear to be corner cases where the DLL seems to take 221 * extra long to lock for reasons that aren't understood. In some 222 * extreme cases we've seen it take up to over 10ms (!). We'll be 223 * generous and give it 50ms. 224 */ 225 ret = regmap_read_poll_timeout(rk_phy->reg_base, 226 rk_phy->reg_offset + GRF_EMMCPHY_STATUS, 227 dllrdy, PHYCTRL_IS_DLLRDY(dllrdy), 228 0, 50 * USEC_PER_MSEC); 229 if (ret) { 230 pr_err("%s: dllrdy failed. ret=%d\n", __func__, ret); 231 return ret; 232 } 233 234 return 0; 235 } 236 237 static int rockchip_emmc_phy_init(struct phy *phy) 238 { 239 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy); 240 int ret = 0; 241 242 /* 243 * We purposely get the clock here and not in probe to avoid the 244 * circular dependency problem. We expect: 245 * - PHY driver to probe 246 * - SDHCI driver to start probe 247 * - SDHCI driver to register it's clock 248 * - SDHCI driver to get the PHY 249 * - SDHCI driver to init the PHY 250 * 251 * The clock is optional, so upon any error we just set to NULL. 252 * 253 * NOTE: we don't do anything special for EPROBE_DEFER here. Given the 254 * above expected use case, EPROBE_DEFER isn't sensible to expect, so 255 * it's just like any other error. 256 */ 257 rk_phy->emmcclk = clk_get(&phy->dev, "emmcclk"); 258 if (IS_ERR(rk_phy->emmcclk)) { 259 dev_dbg(&phy->dev, "Error getting emmcclk: %d\n", ret); 260 rk_phy->emmcclk = NULL; 261 } 262 263 return ret; 264 } 265 266 static int rockchip_emmc_phy_exit(struct phy *phy) 267 { 268 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy); 269 270 clk_put(rk_phy->emmcclk); 271 272 return 0; 273 } 274 275 static int rockchip_emmc_phy_power_off(struct phy *phy) 276 { 277 /* Power down emmc phy analog blocks */ 278 return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_OFF); 279 } 280 281 static int rockchip_emmc_phy_power_on(struct phy *phy) 282 { 283 struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy); 284 285 /* Drive impedance: from DTS */ 286 regmap_write(rk_phy->reg_base, 287 rk_phy->reg_offset + GRF_EMMCPHY_CON6, 288 HIWORD_UPDATE(rk_phy->drive_impedance, 289 PHYCTRL_DR_MASK, 290 PHYCTRL_DR_SHIFT)); 291 292 /* Output tap delay: enable */ 293 regmap_write(rk_phy->reg_base, 294 rk_phy->reg_offset + GRF_EMMCPHY_CON0, 295 HIWORD_UPDATE(PHYCTRL_OTAPDLYENA, 296 PHYCTRL_OTAPDLYENA_MASK, 297 PHYCTRL_OTAPDLYENA_SHIFT)); 298 299 /* Output tap delay */ 300 regmap_write(rk_phy->reg_base, 301 rk_phy->reg_offset + GRF_EMMCPHY_CON0, 302 HIWORD_UPDATE(4, 303 PHYCTRL_OTAPDLYSEL_MASK, 304 PHYCTRL_OTAPDLYSEL_SHIFT)); 305 306 /* Power up emmc phy analog blocks */ 307 return rockchip_emmc_phy_power(phy, PHYCTRL_PDB_PWR_ON); 308 } 309 310 static const struct phy_ops ops = { 311 .init = rockchip_emmc_phy_init, 312 .exit = rockchip_emmc_phy_exit, 313 .power_on = rockchip_emmc_phy_power_on, 314 .power_off = rockchip_emmc_phy_power_off, 315 .owner = THIS_MODULE, 316 }; 317 318 static u32 convert_drive_impedance_ohm(struct platform_device *pdev, u32 dr_ohm) 319 { 320 switch (dr_ohm) { 321 case 100: 322 return PHYCTRL_DR_100OHM; 323 case 66: 324 return PHYCTRL_DR_66OHM; 325 case 50: 326 return PHYCTRL_DR_50OHM; 327 case 40: 328 return PHYCTRL_DR_40OHM; 329 case 33: 330 return PHYCTRL_DR_33OHM; 331 } 332 333 dev_warn(&pdev->dev, "Invalid value %u for drive-impedance-ohm.\n", 334 dr_ohm); 335 return PHYCTRL_DR_50OHM; 336 } 337 338 static int rockchip_emmc_phy_probe(struct platform_device *pdev) 339 { 340 struct device *dev = &pdev->dev; 341 struct rockchip_emmc_phy *rk_phy; 342 struct phy *generic_phy; 343 struct phy_provider *phy_provider; 344 struct regmap *grf; 345 unsigned int reg_offset; 346 u32 val; 347 348 if (!dev->parent || !dev->parent->of_node) 349 return -ENODEV; 350 351 grf = syscon_node_to_regmap(dev->parent->of_node); 352 if (IS_ERR(grf)) { 353 dev_err(dev, "Missing rockchip,grf property\n"); 354 return PTR_ERR(grf); 355 } 356 357 rk_phy = devm_kzalloc(dev, sizeof(*rk_phy), GFP_KERNEL); 358 if (!rk_phy) 359 return -ENOMEM; 360 361 if (of_property_read_u32(dev->of_node, "reg", ®_offset)) { 362 dev_err(dev, "missing reg property in node %pOFn\n", 363 dev->of_node); 364 return -EINVAL; 365 } 366 367 rk_phy->reg_offset = reg_offset; 368 rk_phy->reg_base = grf; 369 rk_phy->drive_impedance = PHYCTRL_DR_50OHM; 370 371 if (!of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val)) 372 rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, val); 373 374 generic_phy = devm_phy_create(dev, dev->of_node, &ops); 375 if (IS_ERR(generic_phy)) { 376 dev_err(dev, "failed to create PHY\n"); 377 return PTR_ERR(generic_phy); 378 } 379 380 phy_set_drvdata(generic_phy, rk_phy); 381 phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate); 382 383 return PTR_ERR_OR_ZERO(phy_provider); 384 } 385 386 static const struct of_device_id rockchip_emmc_phy_dt_ids[] = { 387 { .compatible = "rockchip,rk3399-emmc-phy" }, 388 {} 389 }; 390 391 MODULE_DEVICE_TABLE(of, rockchip_emmc_phy_dt_ids); 392 393 static struct platform_driver rockchip_emmc_driver = { 394 .probe = rockchip_emmc_phy_probe, 395 .driver = { 396 .name = "rockchip-emmc-phy", 397 .of_match_table = rockchip_emmc_phy_dt_ids, 398 }, 399 }; 400 401 module_platform_driver(rockchip_emmc_driver); 402 403 MODULE_AUTHOR("Shawn Lin <shawn.lin@rock-chips.com>"); 404 MODULE_DESCRIPTION("Rockchip EMMC PHY driver"); 405 MODULE_LICENSE("GPL v2"); 406