1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver 4 * 5 * Copyright (C) 2015 Xilinx, Inc. 6 * 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/delay.h> 11 #include <linux/init.h> 12 #include <linux/io.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/rtc.h> 17 18 /* RTC Registers */ 19 #define RTC_SET_TM_WR 0x00 20 #define RTC_SET_TM_RD 0x04 21 #define RTC_CALIB_WR 0x08 22 #define RTC_CALIB_RD 0x0C 23 #define RTC_CUR_TM 0x10 24 #define RTC_CUR_TICK 0x14 25 #define RTC_ALRM 0x18 26 #define RTC_INT_STS 0x20 27 #define RTC_INT_MASK 0x24 28 #define RTC_INT_EN 0x28 29 #define RTC_INT_DIS 0x2C 30 #define RTC_CTRL 0x40 31 32 #define RTC_FR_EN BIT(20) 33 #define RTC_FR_DATSHIFT 16 34 #define RTC_TICK_MASK 0xFFFF 35 #define RTC_INT_SEC BIT(0) 36 #define RTC_INT_ALRM BIT(1) 37 #define RTC_OSC_EN BIT(24) 38 #define RTC_BATT_EN BIT(31) 39 40 #define RTC_CALIB_DEF 0x7FFF 41 #define RTC_CALIB_MASK 0x1FFFFF 42 #define RTC_ALRM_MASK BIT(1) 43 #define RTC_MSEC 1000 44 #define RTC_FR_MASK 0xF0000 45 #define RTC_FR_MAX_TICKS 16 46 #define RTC_PPB 1000000000LL 47 #define RTC_MIN_OFFSET -32768000 48 #define RTC_MAX_OFFSET 32767000 49 50 struct xlnx_rtc_dev { 51 struct rtc_device *rtc; 52 void __iomem *reg_base; 53 int alarm_irq; 54 int sec_irq; 55 struct clk *rtc_clk; 56 unsigned int freq; 57 }; 58 59 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) 60 { 61 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 62 unsigned long new_time; 63 64 /* 65 * The value written will be updated after 1 sec into the 66 * seconds read register, so we need to program time +1 sec 67 * to get the correct time on read. 68 */ 69 new_time = rtc_tm_to_time64(tm) + 1; 70 71 writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR); 72 73 /* 74 * Clear the rtc interrupt status register after setting the 75 * time. During a read_time function, the code should read the 76 * RTC_INT_STATUS register and if bit 0 is still 0, it means 77 * that one second has not elapsed yet since RTC was set and 78 * the current time should be read from SET_TIME_READ register; 79 * otherwise, CURRENT_TIME register is read to report the time 80 */ 81 writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS); 82 83 return 0; 84 } 85 86 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm) 87 { 88 u32 status; 89 unsigned long read_time; 90 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 91 92 status = readl(xrtcdev->reg_base + RTC_INT_STS); 93 94 if (status & RTC_INT_SEC) { 95 /* 96 * RTC has updated the CURRENT_TIME with the time written into 97 * SET_TIME_WRITE register. 98 */ 99 read_time = readl(xrtcdev->reg_base + RTC_CUR_TM); 100 } else { 101 /* 102 * Time written in SET_TIME_WRITE has not yet updated into 103 * the seconds read register, so read the time from the 104 * SET_TIME_WRITE instead of CURRENT_TIME register. 105 * Since we add +1 sec while writing, we need to -1 sec while 106 * reading. 107 */ 108 read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1; 109 } 110 rtc_time64_to_tm(read_time, tm); 111 112 return 0; 113 } 114 115 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 116 { 117 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 118 119 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time); 120 alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM; 121 122 return 0; 123 } 124 125 static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled) 126 { 127 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 128 unsigned int status; 129 ulong timeout; 130 131 timeout = jiffies + msecs_to_jiffies(RTC_MSEC); 132 133 if (enabled) { 134 while (1) { 135 status = readl(xrtcdev->reg_base + RTC_INT_STS); 136 if (!((status & RTC_ALRM_MASK) == RTC_ALRM_MASK)) 137 break; 138 139 if (time_after_eq(jiffies, timeout)) { 140 dev_err(dev, "Time out occur, while clearing alarm status bit\n"); 141 return -ETIMEDOUT; 142 } 143 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS); 144 } 145 146 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN); 147 } else { 148 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS); 149 } 150 151 return 0; 152 } 153 154 static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 155 { 156 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 157 unsigned long alarm_time; 158 159 alarm_time = rtc_tm_to_time64(&alrm->time); 160 161 writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM)); 162 163 xlnx_rtc_alarm_irq_enable(dev, alrm->enabled); 164 165 return 0; 166 } 167 168 static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev) 169 { 170 u32 rtc_ctrl; 171 172 /* Enable RTC switch to battery when VCC_PSAUX is not available */ 173 rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL); 174 rtc_ctrl |= RTC_BATT_EN; 175 writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL); 176 } 177 178 static int xlnx_rtc_read_offset(struct device *dev, long *offset) 179 { 180 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 181 unsigned long long rtc_ppb = RTC_PPB; 182 unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq); 183 unsigned int calibval; 184 long offset_val; 185 186 calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD); 187 /* Offset with seconds ticks */ 188 offset_val = calibval & RTC_TICK_MASK; 189 offset_val = offset_val - RTC_CALIB_DEF; 190 offset_val = offset_val * tick_mult; 191 192 /* Offset with fractional ticks */ 193 if (calibval & RTC_FR_EN) 194 offset_val += ((calibval & RTC_FR_MASK) >> RTC_FR_DATSHIFT) 195 * (tick_mult / RTC_FR_MAX_TICKS); 196 *offset = offset_val; 197 198 return 0; 199 } 200 201 static int xlnx_rtc_set_offset(struct device *dev, long offset) 202 { 203 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 204 unsigned long long rtc_ppb = RTC_PPB; 205 unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq); 206 unsigned char fract_tick = 0; 207 unsigned int calibval; 208 short int max_tick; 209 int fract_offset; 210 211 if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET) 212 return -ERANGE; 213 214 /* Number ticks for given offset */ 215 max_tick = div_s64_rem(offset, tick_mult, &fract_offset); 216 217 /* Number fractional ticks for given offset */ 218 if (fract_offset) { 219 if (fract_offset < 0) { 220 fract_offset = fract_offset + tick_mult; 221 max_tick--; 222 } 223 if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) { 224 for (fract_tick = 1; fract_tick < 16; fract_tick++) { 225 if (fract_offset <= 226 (fract_tick * 227 (tick_mult / RTC_FR_MAX_TICKS))) 228 break; 229 } 230 } 231 } 232 233 /* Zynqmp RTC uses second and fractional tick 234 * counters for compensation 235 */ 236 calibval = max_tick + RTC_CALIB_DEF; 237 238 if (fract_tick) 239 calibval |= RTC_FR_EN; 240 241 calibval |= (fract_tick << RTC_FR_DATSHIFT); 242 243 writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); 244 245 return 0; 246 } 247 248 static const struct rtc_class_ops xlnx_rtc_ops = { 249 .set_time = xlnx_rtc_set_time, 250 .read_time = xlnx_rtc_read_time, 251 .read_alarm = xlnx_rtc_read_alarm, 252 .set_alarm = xlnx_rtc_set_alarm, 253 .alarm_irq_enable = xlnx_rtc_alarm_irq_enable, 254 .read_offset = xlnx_rtc_read_offset, 255 .set_offset = xlnx_rtc_set_offset, 256 }; 257 258 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) 259 { 260 struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id; 261 unsigned int status; 262 263 status = readl(xrtcdev->reg_base + RTC_INT_STS); 264 /* Check if interrupt asserted */ 265 if (!(status & (RTC_INT_SEC | RTC_INT_ALRM))) 266 return IRQ_NONE; 267 268 /* Disable RTC_INT_ALRM interrupt only */ 269 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS); 270 271 if (status & RTC_INT_ALRM) 272 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF); 273 274 return IRQ_HANDLED; 275 } 276 277 static int xlnx_rtc_probe(struct platform_device *pdev) 278 { 279 struct xlnx_rtc_dev *xrtcdev; 280 int ret; 281 282 xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL); 283 if (!xrtcdev) 284 return -ENOMEM; 285 286 platform_set_drvdata(pdev, xrtcdev); 287 288 xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev); 289 if (IS_ERR(xrtcdev->rtc)) 290 return PTR_ERR(xrtcdev->rtc); 291 292 xrtcdev->rtc->ops = &xlnx_rtc_ops; 293 xrtcdev->rtc->range_max = U32_MAX; 294 295 xrtcdev->reg_base = devm_platform_ioremap_resource(pdev, 0); 296 if (IS_ERR(xrtcdev->reg_base)) 297 return PTR_ERR(xrtcdev->reg_base); 298 299 xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm"); 300 if (xrtcdev->alarm_irq < 0) 301 return xrtcdev->alarm_irq; 302 ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq, 303 xlnx_rtc_interrupt, 0, 304 dev_name(&pdev->dev), xrtcdev); 305 if (ret) { 306 dev_err(&pdev->dev, "request irq failed\n"); 307 return ret; 308 } 309 310 xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec"); 311 if (xrtcdev->sec_irq < 0) 312 return xrtcdev->sec_irq; 313 ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq, 314 xlnx_rtc_interrupt, 0, 315 dev_name(&pdev->dev), xrtcdev); 316 if (ret) { 317 dev_err(&pdev->dev, "request irq failed\n"); 318 return ret; 319 } 320 321 /* Getting the rtc_clk info */ 322 xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc_clk"); 323 if (IS_ERR(xrtcdev->rtc_clk)) { 324 if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER) 325 dev_warn(&pdev->dev, "Device clock not found.\n"); 326 } 327 xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk); 328 if (!xrtcdev->freq) { 329 ret = of_property_read_u32(pdev->dev.of_node, "calibration", 330 &xrtcdev->freq); 331 if (ret) 332 xrtcdev->freq = RTC_CALIB_DEF; 333 } 334 ret = readl(xrtcdev->reg_base + RTC_CALIB_RD); 335 if (!ret) 336 writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR)); 337 338 xlnx_init_rtc(xrtcdev); 339 340 device_init_wakeup(&pdev->dev, 1); 341 342 return devm_rtc_register_device(xrtcdev->rtc); 343 } 344 345 static void xlnx_rtc_remove(struct platform_device *pdev) 346 { 347 xlnx_rtc_alarm_irq_enable(&pdev->dev, 0); 348 device_init_wakeup(&pdev->dev, 0); 349 } 350 351 static int __maybe_unused xlnx_rtc_suspend(struct device *dev) 352 { 353 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 354 355 if (device_may_wakeup(dev)) 356 enable_irq_wake(xrtcdev->alarm_irq); 357 else 358 xlnx_rtc_alarm_irq_enable(dev, 0); 359 360 return 0; 361 } 362 363 static int __maybe_unused xlnx_rtc_resume(struct device *dev) 364 { 365 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 366 367 if (device_may_wakeup(dev)) 368 disable_irq_wake(xrtcdev->alarm_irq); 369 else 370 xlnx_rtc_alarm_irq_enable(dev, 1); 371 372 return 0; 373 } 374 375 static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume); 376 377 static const struct of_device_id xlnx_rtc_of_match[] = { 378 {.compatible = "xlnx,zynqmp-rtc" }, 379 { } 380 }; 381 MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match); 382 383 static struct platform_driver xlnx_rtc_driver = { 384 .probe = xlnx_rtc_probe, 385 .remove = xlnx_rtc_remove, 386 .driver = { 387 .name = KBUILD_MODNAME, 388 .pm = &xlnx_rtc_pm_ops, 389 .of_match_table = xlnx_rtc_of_match, 390 }, 391 }; 392 393 module_platform_driver(xlnx_rtc_driver); 394 395 MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver"); 396 MODULE_AUTHOR("Xilinx Inc."); 397 MODULE_LICENSE("GPL v2"); 398