1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de> 4 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net> 5 * JZ4740 SoC RTC driver 6 */ 7 8 #include <linux/clk.h> 9 #include <linux/io.h> 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/of_device.h> 13 #include <linux/platform_device.h> 14 #include <linux/pm_wakeirq.h> 15 #include <linux/reboot.h> 16 #include <linux/rtc.h> 17 #include <linux/slab.h> 18 #include <linux/spinlock.h> 19 20 #define JZ_REG_RTC_CTRL 0x00 21 #define JZ_REG_RTC_SEC 0x04 22 #define JZ_REG_RTC_SEC_ALARM 0x08 23 #define JZ_REG_RTC_REGULATOR 0x0C 24 #define JZ_REG_RTC_HIBERNATE 0x20 25 #define JZ_REG_RTC_WAKEUP_FILTER 0x24 26 #define JZ_REG_RTC_RESET_COUNTER 0x28 27 #define JZ_REG_RTC_SCRATCHPAD 0x34 28 29 /* The following are present on the jz4780 */ 30 #define JZ_REG_RTC_WENR 0x3C 31 #define JZ_RTC_WENR_WEN BIT(31) 32 33 #define JZ_RTC_CTRL_WRDY BIT(7) 34 #define JZ_RTC_CTRL_1HZ BIT(6) 35 #define JZ_RTC_CTRL_1HZ_IRQ BIT(5) 36 #define JZ_RTC_CTRL_AF BIT(4) 37 #define JZ_RTC_CTRL_AF_IRQ BIT(3) 38 #define JZ_RTC_CTRL_AE BIT(2) 39 #define JZ_RTC_CTRL_ENABLE BIT(0) 40 41 /* Magic value to enable writes on jz4780 */ 42 #define JZ_RTC_WENR_MAGIC 0xA55A 43 44 #define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0 45 #define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0 46 47 enum jz4740_rtc_type { 48 ID_JZ4740, 49 ID_JZ4780, 50 }; 51 52 struct jz4740_rtc { 53 void __iomem *base; 54 enum jz4740_rtc_type type; 55 56 struct rtc_device *rtc; 57 struct clk *clk; 58 59 int irq; 60 61 spinlock_t lock; 62 63 unsigned int min_wakeup_pin_assert_time; 64 unsigned int reset_pin_assert_time; 65 }; 66 67 static struct device *dev_for_power_off; 68 69 static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg) 70 { 71 return readl(rtc->base + reg); 72 } 73 74 static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc) 75 { 76 uint32_t ctrl; 77 int timeout = 10000; 78 79 do { 80 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); 81 } while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout); 82 83 return timeout ? 0 : -EIO; 84 } 85 86 static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc) 87 { 88 uint32_t ctrl; 89 int ret, timeout = 10000; 90 91 ret = jz4740_rtc_wait_write_ready(rtc); 92 if (ret != 0) 93 return ret; 94 95 writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR); 96 97 do { 98 ctrl = readl(rtc->base + JZ_REG_RTC_WENR); 99 } while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout); 100 101 return timeout ? 0 : -EIO; 102 } 103 104 static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg, 105 uint32_t val) 106 { 107 int ret = 0; 108 109 if (rtc->type >= ID_JZ4780) 110 ret = jz4780_rtc_enable_write(rtc); 111 if (ret == 0) 112 ret = jz4740_rtc_wait_write_ready(rtc); 113 if (ret == 0) 114 writel(val, rtc->base + reg); 115 116 return ret; 117 } 118 119 static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask, 120 bool set) 121 { 122 int ret; 123 unsigned long flags; 124 uint32_t ctrl; 125 126 spin_lock_irqsave(&rtc->lock, flags); 127 128 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); 129 130 /* Don't clear interrupt flags by accident */ 131 ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF; 132 133 if (set) 134 ctrl |= mask; 135 else 136 ctrl &= ~mask; 137 138 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl); 139 140 spin_unlock_irqrestore(&rtc->lock, flags); 141 142 return ret; 143 } 144 145 static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time) 146 { 147 struct jz4740_rtc *rtc = dev_get_drvdata(dev); 148 uint32_t secs, secs2; 149 int timeout = 5; 150 151 if (jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD) != 0x12345678) 152 return -EINVAL; 153 154 /* If the seconds register is read while it is updated, it can contain a 155 * bogus value. This can be avoided by making sure that two consecutive 156 * reads have the same value. 157 */ 158 secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC); 159 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC); 160 161 while (secs != secs2 && --timeout) { 162 secs = secs2; 163 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC); 164 } 165 166 if (timeout == 0) 167 return -EIO; 168 169 rtc_time64_to_tm(secs, time); 170 171 return 0; 172 } 173 174 static int jz4740_rtc_set_time(struct device *dev, struct rtc_time *time) 175 { 176 struct jz4740_rtc *rtc = dev_get_drvdata(dev); 177 int ret; 178 179 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time)); 180 if (ret) 181 return ret; 182 183 return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678); 184 } 185 186 static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 187 { 188 struct jz4740_rtc *rtc = dev_get_drvdata(dev); 189 uint32_t secs; 190 uint32_t ctrl; 191 192 secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM); 193 194 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); 195 196 alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE); 197 alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF); 198 199 rtc_time64_to_tm(secs, &alrm->time); 200 201 return 0; 202 } 203 204 static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 205 { 206 int ret; 207 struct jz4740_rtc *rtc = dev_get_drvdata(dev); 208 uint32_t secs = lower_32_bits(rtc_tm_to_time64(&alrm->time)); 209 210 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs); 211 if (!ret) 212 ret = jz4740_rtc_ctrl_set_bits(rtc, 213 JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled); 214 215 return ret; 216 } 217 218 static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) 219 { 220 struct jz4740_rtc *rtc = dev_get_drvdata(dev); 221 return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable); 222 } 223 224 static const struct rtc_class_ops jz4740_rtc_ops = { 225 .read_time = jz4740_rtc_read_time, 226 .set_time = jz4740_rtc_set_time, 227 .read_alarm = jz4740_rtc_read_alarm, 228 .set_alarm = jz4740_rtc_set_alarm, 229 .alarm_irq_enable = jz4740_rtc_alarm_irq_enable, 230 }; 231 232 static irqreturn_t jz4740_rtc_irq(int irq, void *data) 233 { 234 struct jz4740_rtc *rtc = data; 235 uint32_t ctrl; 236 unsigned long events = 0; 237 238 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); 239 240 if (ctrl & JZ_RTC_CTRL_1HZ) 241 events |= (RTC_UF | RTC_IRQF); 242 243 if (ctrl & JZ_RTC_CTRL_AF) 244 events |= (RTC_AF | RTC_IRQF); 245 246 rtc_update_irq(rtc->rtc, 1, events); 247 248 jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false); 249 250 return IRQ_HANDLED; 251 } 252 253 static void jz4740_rtc_poweroff(struct device *dev) 254 { 255 struct jz4740_rtc *rtc = dev_get_drvdata(dev); 256 jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1); 257 } 258 259 static void jz4740_rtc_power_off(void) 260 { 261 struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off); 262 unsigned long rtc_rate; 263 unsigned long wakeup_filter_ticks; 264 unsigned long reset_counter_ticks; 265 266 clk_prepare_enable(rtc->clk); 267 268 rtc_rate = clk_get_rate(rtc->clk); 269 270 /* 271 * Set minimum wakeup pin assertion time: 100 ms. 272 * Range is 0 to 2 sec if RTC is clocked at 32 kHz. 273 */ 274 wakeup_filter_ticks = 275 (rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000; 276 if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK) 277 wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK; 278 else 279 wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK; 280 jz4740_rtc_reg_write(rtc, 281 JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks); 282 283 /* 284 * Set reset pin low-level assertion time after wakeup: 60 ms. 285 * Range is 0 to 125 ms if RTC is clocked at 32 kHz. 286 */ 287 reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000; 288 if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK) 289 reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK; 290 else 291 reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK; 292 jz4740_rtc_reg_write(rtc, 293 JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks); 294 295 jz4740_rtc_poweroff(dev_for_power_off); 296 kernel_halt(); 297 } 298 299 static const struct of_device_id jz4740_rtc_of_match[] = { 300 { .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 }, 301 { .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 }, 302 {}, 303 }; 304 MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match); 305 306 static int jz4740_rtc_probe(struct platform_device *pdev) 307 { 308 int ret; 309 struct jz4740_rtc *rtc; 310 const struct platform_device_id *id = platform_get_device_id(pdev); 311 const struct of_device_id *of_id = of_match_device( 312 jz4740_rtc_of_match, &pdev->dev); 313 struct device_node *np = pdev->dev.of_node; 314 315 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); 316 if (!rtc) 317 return -ENOMEM; 318 319 if (of_id) 320 rtc->type = (enum jz4740_rtc_type)of_id->data; 321 else 322 rtc->type = id->driver_data; 323 324 rtc->irq = platform_get_irq(pdev, 0); 325 if (rtc->irq < 0) 326 return -ENOENT; 327 328 rtc->base = devm_platform_ioremap_resource(pdev, 0); 329 if (IS_ERR(rtc->base)) 330 return PTR_ERR(rtc->base); 331 332 rtc->clk = devm_clk_get(&pdev->dev, "rtc"); 333 if (IS_ERR(rtc->clk)) { 334 dev_err(&pdev->dev, "Failed to get RTC clock\n"); 335 return PTR_ERR(rtc->clk); 336 } 337 338 spin_lock_init(&rtc->lock); 339 340 platform_set_drvdata(pdev, rtc); 341 342 device_init_wakeup(&pdev->dev, 1); 343 344 ret = dev_pm_set_wake_irq(&pdev->dev, rtc->irq); 345 if (ret) { 346 dev_err(&pdev->dev, "Failed to set wake irq: %d\n", ret); 347 return ret; 348 } 349 350 rtc->rtc = devm_rtc_allocate_device(&pdev->dev); 351 if (IS_ERR(rtc->rtc)) { 352 ret = PTR_ERR(rtc->rtc); 353 dev_err(&pdev->dev, "Failed to allocate rtc device: %d\n", ret); 354 return ret; 355 } 356 357 rtc->rtc->ops = &jz4740_rtc_ops; 358 rtc->rtc->range_max = U32_MAX; 359 360 ret = rtc_register_device(rtc->rtc); 361 if (ret) 362 return ret; 363 364 ret = devm_request_irq(&pdev->dev, rtc->irq, jz4740_rtc_irq, 0, 365 pdev->name, rtc); 366 if (ret) { 367 dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret); 368 return ret; 369 } 370 371 if (np && of_device_is_system_power_controller(np)) { 372 if (!pm_power_off) { 373 /* Default: 60ms */ 374 rtc->reset_pin_assert_time = 60; 375 of_property_read_u32(np, "reset-pin-assert-time-ms", 376 &rtc->reset_pin_assert_time); 377 378 /* Default: 100ms */ 379 rtc->min_wakeup_pin_assert_time = 100; 380 of_property_read_u32(np, 381 "min-wakeup-pin-assert-time-ms", 382 &rtc->min_wakeup_pin_assert_time); 383 384 dev_for_power_off = &pdev->dev; 385 pm_power_off = jz4740_rtc_power_off; 386 } else { 387 dev_warn(&pdev->dev, 388 "Poweroff handler already present!\n"); 389 } 390 } 391 392 return 0; 393 } 394 395 static const struct platform_device_id jz4740_rtc_ids[] = { 396 { "jz4740-rtc", ID_JZ4740 }, 397 { "jz4780-rtc", ID_JZ4780 }, 398 {} 399 }; 400 MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids); 401 402 static struct platform_driver jz4740_rtc_driver = { 403 .probe = jz4740_rtc_probe, 404 .driver = { 405 .name = "jz4740-rtc", 406 .of_match_table = of_match_ptr(jz4740_rtc_of_match), 407 }, 408 .id_table = jz4740_rtc_ids, 409 }; 410 411 module_platform_driver(jz4740_rtc_driver); 412 413 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 414 MODULE_LICENSE("GPL"); 415 MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n"); 416 MODULE_ALIAS("platform:jz4740-rtc"); 417