1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver for Skyworks Si521xx PCIe clock generator driver 4 * 5 * The following series can be supported: 6 * - Si52144 - 4x DIFF 7 * - Si52146 - 6x DIFF 8 * - Si52147 - 9x DIFF 9 * Currently tested: 10 * - Si52144 11 * 12 * Copyright (C) 2022 Marek Vasut <marex@denx.de> 13 */ 14 15 #include <linux/bitfield.h> 16 #include <linux/bitrev.h> 17 #include <linux/clk-provider.h> 18 #include <linux/i2c.h> 19 #include <linux/mod_devicetable.h> 20 #include <linux/module.h> 21 #include <linux/of.h> 22 #include <linux/regmap.h> 23 24 /* OE1 and OE2 register */ 25 #define SI521XX_REG_OE(n) (((n) & 0x1) + 1) 26 #define SI521XX_REG_ID 0x3 27 #define SI521XX_REG_ID_PROG GENMASK(7, 4) 28 #define SI521XX_REG_ID_VENDOR GENMASK(3, 0) 29 #define SI521XX_REG_BC 0x4 30 #define SI521XX_REG_DA 0x5 31 #define SI521XX_REG_DA_AMP_SEL BIT(7) 32 #define SI521XX_REG_DA_AMP_MASK GENMASK(6, 4) 33 #define SI521XX_REG_DA_AMP_MIN 300000 34 #define SI521XX_REG_DA_AMP_DEFAULT 800000 35 #define SI521XX_REG_DA_AMP_MAX 1000000 36 #define SI521XX_REG_DA_AMP_STEP 100000 37 #define SI521XX_REG_DA_AMP(UV) \ 38 FIELD_PREP(SI521XX_REG_DA_AMP_MASK, \ 39 ((UV) - SI521XX_REG_DA_AMP_MIN) / SI521XX_REG_DA_AMP_STEP) 40 #define SI521XX_REG_DA_UNKNOWN BIT(3) /* Always set */ 41 42 /* Count of populated OE bits in control register ref, 1 and 2 */ 43 #define SI521XX_OE_MAP(cr1, cr2) (((cr2) << 8) | (cr1)) 44 #define SI521XX_OE_MAP_GET_OE(oe, map) (((map) >> (((oe) - 1) * 8)) & 0xff) 45 46 #define SI521XX_DIFF_MULT 4 47 #define SI521XX_DIFF_DIV 1 48 49 /* Supported Skyworks Si521xx models. */ 50 enum si521xx_model { 51 SI52144 = 0x44, 52 SI52146 = 0x46, 53 SI52147 = 0x47, 54 }; 55 56 struct si521xx; 57 58 struct si_clk { 59 struct clk_hw hw; 60 struct si521xx *si; 61 u8 reg; 62 u8 bit; 63 }; 64 65 struct si521xx { 66 struct i2c_client *client; 67 struct regmap *regmap; 68 struct si_clk clk_dif[9]; 69 u16 chip_info; 70 u8 pll_amplitude; 71 }; 72 73 /* 74 * Si521xx i2c regmap 75 */ 76 static const struct regmap_range si521xx_readable_ranges[] = { 77 regmap_reg_range(SI521XX_REG_OE(0), SI521XX_REG_DA), 78 }; 79 80 static const struct regmap_access_table si521xx_readable_table = { 81 .yes_ranges = si521xx_readable_ranges, 82 .n_yes_ranges = ARRAY_SIZE(si521xx_readable_ranges), 83 }; 84 85 static const struct regmap_range si521xx_writeable_ranges[] = { 86 regmap_reg_range(SI521XX_REG_OE(0), SI521XX_REG_OE(1)), 87 regmap_reg_range(SI521XX_REG_BC, SI521XX_REG_DA), 88 }; 89 90 static const struct regmap_access_table si521xx_writeable_table = { 91 .yes_ranges = si521xx_writeable_ranges, 92 .n_yes_ranges = ARRAY_SIZE(si521xx_writeable_ranges), 93 }; 94 95 static int si521xx_regmap_i2c_write(void *context, unsigned int reg, 96 unsigned int val) 97 { 98 struct i2c_client *i2c = context; 99 const u8 data[3] = { reg, 1, val }; 100 const int count = ARRAY_SIZE(data); 101 int ret; 102 103 ret = i2c_master_send(i2c, data, count); 104 if (ret == count) 105 return 0; 106 else if (ret < 0) 107 return ret; 108 else 109 return -EIO; 110 } 111 112 static int si521xx_regmap_i2c_read(void *context, unsigned int reg, 113 unsigned int *val) 114 { 115 struct i2c_client *i2c = context; 116 struct i2c_msg xfer[2]; 117 u8 txdata = reg; 118 u8 rxdata[2]; 119 int ret; 120 121 xfer[0].addr = i2c->addr; 122 xfer[0].flags = 0; 123 xfer[0].len = 1; 124 xfer[0].buf = (void *)&txdata; 125 126 xfer[1].addr = i2c->addr; 127 xfer[1].flags = I2C_M_RD; 128 xfer[1].len = 2; 129 xfer[1].buf = (void *)rxdata; 130 131 ret = i2c_transfer(i2c->adapter, xfer, 2); 132 if (ret < 0) 133 return ret; 134 if (ret != 2) 135 return -EIO; 136 137 /* 138 * Byte 0 is transfer length, which is always 1 due 139 * to BCP register programming to 1 in si521xx_probe(), 140 * ignore it and use data from Byte 1. 141 */ 142 *val = rxdata[1]; 143 return 0; 144 } 145 146 static const struct regmap_config si521xx_regmap_config = { 147 .reg_bits = 8, 148 .val_bits = 8, 149 .cache_type = REGCACHE_NONE, 150 .max_register = SI521XX_REG_DA, 151 .rd_table = &si521xx_readable_table, 152 .wr_table = &si521xx_writeable_table, 153 .reg_write = si521xx_regmap_i2c_write, 154 .reg_read = si521xx_regmap_i2c_read, 155 }; 156 157 static unsigned long si521xx_diff_recalc_rate(struct clk_hw *hw, 158 unsigned long parent_rate) 159 { 160 unsigned long long rate; 161 162 rate = (unsigned long long)parent_rate * SI521XX_DIFF_MULT; 163 do_div(rate, SI521XX_DIFF_DIV); 164 return (unsigned long)rate; 165 } 166 167 static long si521xx_diff_round_rate(struct clk_hw *hw, unsigned long rate, 168 unsigned long *prate) 169 { 170 unsigned long best_parent; 171 172 best_parent = (rate / SI521XX_DIFF_MULT) * SI521XX_DIFF_DIV; 173 *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent); 174 175 return (*prate / SI521XX_DIFF_DIV) * SI521XX_DIFF_MULT; 176 } 177 178 static int si521xx_diff_set_rate(struct clk_hw *hw, unsigned long rate, 179 unsigned long parent_rate) 180 { 181 /* 182 * We must report success but we can do so unconditionally because 183 * si521xx_diff_round_rate returns values that ensure this call is a 184 * nop. 185 */ 186 187 return 0; 188 } 189 190 #define to_si521xx_clk(_hw) container_of(_hw, struct si_clk, hw) 191 192 static int si521xx_diff_prepare(struct clk_hw *hw) 193 { 194 struct si_clk *si_clk = to_si521xx_clk(hw); 195 struct si521xx *si = si_clk->si; 196 197 regmap_set_bits(si->regmap, SI521XX_REG_OE(si_clk->reg), si_clk->bit); 198 199 return 0; 200 } 201 202 static void si521xx_diff_unprepare(struct clk_hw *hw) 203 { 204 struct si_clk *si_clk = to_si521xx_clk(hw); 205 struct si521xx *si = si_clk->si; 206 207 regmap_clear_bits(si->regmap, SI521XX_REG_OE(si_clk->reg), si_clk->bit); 208 } 209 210 static const struct clk_ops si521xx_diff_clk_ops = { 211 .round_rate = si521xx_diff_round_rate, 212 .set_rate = si521xx_diff_set_rate, 213 .recalc_rate = si521xx_diff_recalc_rate, 214 .prepare = si521xx_diff_prepare, 215 .unprepare = si521xx_diff_unprepare, 216 }; 217 218 static int si521xx_get_common_config(struct si521xx *si) 219 { 220 struct i2c_client *client = si->client; 221 struct device_node *np = client->dev.of_node; 222 unsigned int amp; 223 int ret; 224 225 /* Set defaults */ 226 si->pll_amplitude = SI521XX_REG_DA_AMP(SI521XX_REG_DA_AMP_DEFAULT); 227 228 /* Output clock amplitude */ 229 ret = of_property_read_u32(np, "skyworks,out-amplitude-microvolt", 230 &); 231 if (!ret) { 232 if (amp < SI521XX_REG_DA_AMP_MIN || amp > SI521XX_REG_DA_AMP_MAX || 233 amp % SI521XX_REG_DA_AMP_STEP) { 234 return dev_err_probe(&client->dev, -EINVAL, 235 "Invalid skyworks,out-amplitude-microvolt value\n"); 236 } 237 si->pll_amplitude = SI521XX_REG_DA_AMP(amp); 238 } 239 240 return 0; 241 } 242 243 static void si521xx_update_config(struct si521xx *si) 244 { 245 /* If amplitude is non-default, update it. */ 246 if (si->pll_amplitude == SI521XX_REG_DA_AMP(SI521XX_REG_DA_AMP_DEFAULT)) 247 return; 248 249 regmap_update_bits(si->regmap, SI521XX_REG_DA, 250 SI521XX_REG_DA_AMP_MASK, si->pll_amplitude); 251 } 252 253 static void si521xx_diff_idx_to_reg_bit(const u16 chip_info, const int idx, 254 struct si_clk *clk) 255 { 256 unsigned long mask; 257 int oe, b, ctr = 0; 258 259 for (oe = 1; oe <= 2; oe++) { 260 mask = bitrev8(SI521XX_OE_MAP_GET_OE(oe, chip_info)); 261 for_each_set_bit(b, &mask, 8) { 262 if (ctr++ != idx) 263 continue; 264 clk->reg = SI521XX_REG_OE(oe); 265 clk->bit = 7 - b; 266 return; 267 } 268 } 269 } 270 271 static struct clk_hw * 272 si521xx_of_clk_get(struct of_phandle_args *clkspec, void *data) 273 { 274 struct si521xx *si = data; 275 unsigned int idx = clkspec->args[0]; 276 277 return &si->clk_dif[idx].hw; 278 } 279 280 static int si521xx_probe(struct i2c_client *client) 281 { 282 const u16 chip_info = (u16)(uintptr_t)device_get_match_data(&client->dev); 283 const struct clk_parent_data clk_parent_data = { .index = 0 }; 284 struct si521xx *si; 285 unsigned char name[6] = "DIFF0"; 286 struct clk_init_data init = {}; 287 int i, ret; 288 289 if (!chip_info) 290 return -EINVAL; 291 292 si = devm_kzalloc(&client->dev, sizeof(*si), GFP_KERNEL); 293 if (!si) 294 return -ENOMEM; 295 296 i2c_set_clientdata(client, si); 297 si->client = client; 298 299 /* Fetch common configuration from DT (if specified) */ 300 ret = si521xx_get_common_config(si); 301 if (ret) 302 return ret; 303 304 si->regmap = devm_regmap_init(&client->dev, NULL, client, 305 &si521xx_regmap_config); 306 if (IS_ERR(si->regmap)) 307 return dev_err_probe(&client->dev, PTR_ERR(si->regmap), 308 "Failed to allocate register map\n"); 309 310 /* Always read back 1 Byte via I2C */ 311 ret = regmap_write(si->regmap, SI521XX_REG_BC, 1); 312 if (ret < 0) 313 return ret; 314 315 /* Register clock */ 316 for (i = 0; i < hweight16(chip_info); i++) { 317 memset(&init, 0, sizeof(init)); 318 snprintf(name, 6, "DIFF%d", i); 319 init.name = name; 320 init.ops = &si521xx_diff_clk_ops; 321 init.parent_data = &clk_parent_data; 322 init.num_parents = 1; 323 init.flags = CLK_SET_RATE_PARENT; 324 325 si->clk_dif[i].hw.init = &init; 326 si->clk_dif[i].si = si; 327 328 si521xx_diff_idx_to_reg_bit(chip_info, i, &si->clk_dif[i]); 329 330 ret = devm_clk_hw_register(&client->dev, &si->clk_dif[i].hw); 331 if (ret) 332 return ret; 333 } 334 335 ret = devm_of_clk_add_hw_provider(&client->dev, si521xx_of_clk_get, si); 336 if (!ret) 337 si521xx_update_config(si); 338 339 return ret; 340 } 341 342 static int __maybe_unused si521xx_suspend(struct device *dev) 343 { 344 struct si521xx *si = dev_get_drvdata(dev); 345 346 regcache_cache_only(si->regmap, true); 347 regcache_mark_dirty(si->regmap); 348 349 return 0; 350 } 351 352 static int __maybe_unused si521xx_resume(struct device *dev) 353 { 354 struct si521xx *si = dev_get_drvdata(dev); 355 int ret; 356 357 regcache_cache_only(si->regmap, false); 358 ret = regcache_sync(si->regmap); 359 if (ret) 360 dev_err(dev, "Failed to restore register map: %d\n", ret); 361 return ret; 362 } 363 364 static const struct i2c_device_id si521xx_id[] = { 365 { "si52144", .driver_data = SI521XX_OE_MAP(0x5, 0xc0) }, 366 { "si52146", .driver_data = SI521XX_OE_MAP(0x15, 0xe0) }, 367 { "si52147", .driver_data = SI521XX_OE_MAP(0x17, 0xf8) }, 368 { } 369 }; 370 MODULE_DEVICE_TABLE(i2c, si521xx_id); 371 372 static const struct of_device_id clk_si521xx_of_match[] = { 373 { .compatible = "skyworks,si52144", .data = (void *)SI521XX_OE_MAP(0x5, 0xc0) }, 374 { .compatible = "skyworks,si52146", .data = (void *)SI521XX_OE_MAP(0x15, 0xe0) }, 375 { .compatible = "skyworks,si52147", .data = (void *)SI521XX_OE_MAP(0x15, 0xf8) }, 376 { } 377 }; 378 MODULE_DEVICE_TABLE(of, clk_si521xx_of_match); 379 380 static SIMPLE_DEV_PM_OPS(si521xx_pm_ops, si521xx_suspend, si521xx_resume); 381 382 static struct i2c_driver si521xx_driver = { 383 .driver = { 384 .name = "clk-si521xx", 385 .pm = &si521xx_pm_ops, 386 .of_match_table = clk_si521xx_of_match, 387 }, 388 .probe_new = si521xx_probe, 389 .id_table = si521xx_id, 390 }; 391 module_i2c_driver(si521xx_driver); 392 393 MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); 394 MODULE_DESCRIPTION("Skyworks Si521xx PCIe clock generator driver"); 395 MODULE_LICENSE("GPL"); 396