1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Freescale STMP37XX/STMP378X Real Time Clock driver 4 * 5 * Copyright (c) 2007 Sigmatel, Inc. 6 * Peter Hartley, <peter.hartley@sigmatel.com> 7 * 8 * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved. 9 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. 10 * Copyright 2011 Wolfram Sang, Pengutronix e.K. 11 */ 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/io.h> 15 #include <linux/init.h> 16 #include <linux/platform_device.h> 17 #include <linux/interrupt.h> 18 #include <linux/delay.h> 19 #include <linux/rtc.h> 20 #include <linux/slab.h> 21 #include <linux/of_device.h> 22 #include <linux/of.h> 23 #include <linux/stmp_device.h> 24 #include <linux/stmp3xxx_rtc_wdt.h> 25 26 #define STMP3XXX_RTC_CTRL 0x0 27 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001 28 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN 0x00000002 29 #define STMP3XXX_RTC_CTRL_ALARM_IRQ 0x00000004 30 #define STMP3XXX_RTC_CTRL_WATCHDOGEN 0x00000010 31 32 #define STMP3XXX_RTC_STAT 0x10 33 #define STMP3XXX_RTC_STAT_STALE_SHIFT 16 34 #define STMP3XXX_RTC_STAT_RTC_PRESENT 0x80000000 35 #define STMP3XXX_RTC_STAT_XTAL32000_PRESENT 0x10000000 36 #define STMP3XXX_RTC_STAT_XTAL32768_PRESENT 0x08000000 37 38 #define STMP3XXX_RTC_SECONDS 0x30 39 40 #define STMP3XXX_RTC_ALARM 0x40 41 42 #define STMP3XXX_RTC_WATCHDOG 0x50 43 44 #define STMP3XXX_RTC_PERSISTENT0 0x60 45 #define STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE (1 << 0) 46 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN (1 << 1) 47 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN (1 << 2) 48 #define STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP (1 << 4) 49 #define STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP (1 << 5) 50 #define STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ (1 << 6) 51 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE (1 << 7) 52 53 #define STMP3XXX_RTC_PERSISTENT1 0x70 54 /* missing bitmask in headers */ 55 #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000 56 57 struct stmp3xxx_rtc_data { 58 struct rtc_device *rtc; 59 void __iomem *io; 60 int irq_alarm; 61 }; 62 63 #if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG) 64 /** 65 * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC 66 * @dev: the parent device of the watchdog (= the RTC) 67 * @timeout: the desired value for the timeout register of the watchdog. 68 * 0 disables the watchdog 69 * 70 * The watchdog needs one register and two bits which are in the RTC domain. 71 * To handle the resource conflict, the RTC driver will create another 72 * platform_device for the watchdog driver as a child of the RTC device. 73 * The watchdog driver is passed the below accessor function via platform_data 74 * to configure the watchdog. Locking is not needed because accessing SET/CLR 75 * registers is atomic. 76 */ 77 78 static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout) 79 { 80 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 81 82 if (timeout) { 83 writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG); 84 writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, 85 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET); 86 writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER, 87 rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET); 88 } else { 89 writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, 90 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); 91 writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER, 92 rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR); 93 } 94 } 95 96 static struct stmp3xxx_wdt_pdata wdt_pdata = { 97 .wdt_set_timeout = stmp3xxx_wdt_set_timeout, 98 }; 99 100 static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev) 101 { 102 int rc = -1; 103 struct platform_device *wdt_pdev = 104 platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id); 105 106 if (wdt_pdev) { 107 wdt_pdev->dev.parent = &rtc_pdev->dev; 108 wdt_pdev->dev.platform_data = &wdt_pdata; 109 rc = platform_device_add(wdt_pdev); 110 } 111 112 if (rc) 113 dev_err(&rtc_pdev->dev, 114 "failed to register stmp3xxx_rtc_wdt\n"); 115 } 116 #else 117 static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev) 118 { 119 } 120 #endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */ 121 122 static int stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data) 123 { 124 int timeout = 5000; /* 3ms according to i.MX28 Ref Manual */ 125 /* 126 * The i.MX28 Applications Processor Reference Manual, Rev. 1, 2010 127 * states: 128 * | The order in which registers are updated is 129 * | Persistent 0, 1, 2, 3, 4, 5, Alarm, Seconds. 130 * | (This list is in bitfield order, from LSB to MSB, as they would 131 * | appear in the STALE_REGS and NEW_REGS bitfields of the HW_RTC_STAT 132 * | register. For example, the Seconds register corresponds to 133 * | STALE_REGS or NEW_REGS containing 0x80.) 134 */ 135 do { 136 if (!(readl(rtc_data->io + STMP3XXX_RTC_STAT) & 137 (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))) 138 return 0; 139 udelay(1); 140 } while (--timeout > 0); 141 return (readl(rtc_data->io + STMP3XXX_RTC_STAT) & 142 (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT)) ? -ETIME : 0; 143 } 144 145 /* Time read/write */ 146 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm) 147 { 148 int ret; 149 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 150 151 ret = stmp3xxx_wait_time(rtc_data); 152 if (ret) 153 return ret; 154 155 rtc_time64_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm); 156 return 0; 157 } 158 159 static int stmp3xxx_rtc_settime(struct device *dev, struct rtc_time *rtc_tm) 160 { 161 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 162 163 writel(rtc_tm_to_time64(rtc_tm), rtc_data->io + STMP3XXX_RTC_SECONDS); 164 return stmp3xxx_wait_time(rtc_data); 165 } 166 167 /* interrupt(s) handler */ 168 static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id) 169 { 170 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id); 171 u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL); 172 173 if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) { 174 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ, 175 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); 176 rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF); 177 return IRQ_HANDLED; 178 } 179 180 return IRQ_NONE; 181 } 182 183 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled) 184 { 185 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 186 187 if (enabled) { 188 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | 189 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN, 190 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + 191 STMP_OFFSET_REG_SET); 192 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, 193 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET); 194 } else { 195 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | 196 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN, 197 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + 198 STMP_OFFSET_REG_CLR); 199 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, 200 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); 201 } 202 return 0; 203 } 204 205 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) 206 { 207 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 208 209 rtc_time64_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time); 210 return 0; 211 } 212 213 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) 214 { 215 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 216 217 writel(rtc_tm_to_time64(&alm->time), rtc_data->io + STMP3XXX_RTC_ALARM); 218 219 stmp3xxx_alarm_irq_enable(dev, alm->enabled); 220 221 return 0; 222 } 223 224 static const struct rtc_class_ops stmp3xxx_rtc_ops = { 225 .alarm_irq_enable = 226 stmp3xxx_alarm_irq_enable, 227 .read_time = stmp3xxx_rtc_gettime, 228 .set_time = stmp3xxx_rtc_settime, 229 .read_alarm = stmp3xxx_rtc_read_alarm, 230 .set_alarm = stmp3xxx_rtc_set_alarm, 231 }; 232 233 static int stmp3xxx_rtc_remove(struct platform_device *pdev) 234 { 235 struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev); 236 237 if (!rtc_data) 238 return 0; 239 240 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, 241 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); 242 243 return 0; 244 } 245 246 static int stmp3xxx_rtc_probe(struct platform_device *pdev) 247 { 248 struct stmp3xxx_rtc_data *rtc_data; 249 struct resource *r; 250 u32 rtc_stat; 251 u32 pers0_set, pers0_clr; 252 u32 crystalfreq = 0; 253 int err; 254 255 rtc_data = devm_kzalloc(&pdev->dev, sizeof(*rtc_data), GFP_KERNEL); 256 if (!rtc_data) 257 return -ENOMEM; 258 259 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 260 if (!r) { 261 dev_err(&pdev->dev, "failed to get resource\n"); 262 return -ENXIO; 263 } 264 265 rtc_data->io = devm_ioremap(&pdev->dev, r->start, resource_size(r)); 266 if (!rtc_data->io) { 267 dev_err(&pdev->dev, "ioremap failed\n"); 268 return -EIO; 269 } 270 271 rtc_data->irq_alarm = platform_get_irq(pdev, 0); 272 273 rtc_stat = readl(rtc_data->io + STMP3XXX_RTC_STAT); 274 if (!(rtc_stat & STMP3XXX_RTC_STAT_RTC_PRESENT)) { 275 dev_err(&pdev->dev, "no device onboard\n"); 276 return -ENODEV; 277 } 278 279 platform_set_drvdata(pdev, rtc_data); 280 281 /* 282 * Resetting the rtc stops the watchdog timer that is potentially 283 * running. So (assuming it is running on purpose) don't reset if the 284 * watchdog is enabled. 285 */ 286 if (readl(rtc_data->io + STMP3XXX_RTC_CTRL) & 287 STMP3XXX_RTC_CTRL_WATCHDOGEN) { 288 dev_info(&pdev->dev, 289 "Watchdog is running, skip resetting rtc\n"); 290 } else { 291 err = stmp_reset_block(rtc_data->io); 292 if (err) { 293 dev_err(&pdev->dev, "stmp_reset_block failed: %d\n", 294 err); 295 return err; 296 } 297 } 298 299 /* 300 * Obviously the rtc needs a clock input to be able to run. 301 * This clock can be provided by an external 32k crystal. If that one is 302 * missing XTAL must not be disabled in suspend which consumes a 303 * lot of power. Normally the presence and exact frequency (supported 304 * are 32000 Hz and 32768 Hz) is detectable from fuses, but as reality 305 * proves these fuses are not blown correctly on all machines, so the 306 * frequency can be overridden in the device tree. 307 */ 308 if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32000_PRESENT) 309 crystalfreq = 32000; 310 else if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32768_PRESENT) 311 crystalfreq = 32768; 312 313 of_property_read_u32(pdev->dev.of_node, "stmp,crystal-freq", 314 &crystalfreq); 315 316 switch (crystalfreq) { 317 case 32000: 318 /* keep 32kHz crystal running in low-power mode */ 319 pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | 320 STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | 321 STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE; 322 pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP; 323 break; 324 case 32768: 325 /* keep 32.768kHz crystal running in low-power mode */ 326 pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | 327 STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE; 328 pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP | 329 STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ; 330 break; 331 default: 332 dev_warn(&pdev->dev, 333 "invalid crystal-freq specified in device-tree. Assuming no crystal\n"); 334 /* fall-through */ 335 case 0: 336 /* keep XTAL on in low-power mode */ 337 pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP; 338 pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | 339 STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE; 340 } 341 342 writel(pers0_set, rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + 343 STMP_OFFSET_REG_SET); 344 345 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | 346 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN | 347 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE | pers0_clr, 348 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR); 349 350 writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN | 351 STMP3XXX_RTC_CTRL_ALARM_IRQ_EN, 352 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); 353 354 rtc_data->rtc = devm_rtc_allocate_device(&pdev->dev); 355 if (IS_ERR(rtc_data->rtc)) 356 return PTR_ERR(rtc_data->rtc); 357 358 err = devm_request_irq(&pdev->dev, rtc_data->irq_alarm, 359 stmp3xxx_rtc_interrupt, 0, "RTC alarm", &pdev->dev); 360 if (err) { 361 dev_err(&pdev->dev, "Cannot claim IRQ%d\n", 362 rtc_data->irq_alarm); 363 return err; 364 } 365 366 rtc_data->rtc->ops = &stmp3xxx_rtc_ops; 367 rtc_data->rtc->range_max = U32_MAX; 368 369 err = rtc_register_device(rtc_data->rtc); 370 if (err) 371 return err; 372 373 stmp3xxx_wdt_register(pdev); 374 return 0; 375 } 376 377 #ifdef CONFIG_PM_SLEEP 378 static int stmp3xxx_rtc_suspend(struct device *dev) 379 { 380 return 0; 381 } 382 383 static int stmp3xxx_rtc_resume(struct device *dev) 384 { 385 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); 386 387 stmp_reset_block(rtc_data->io); 388 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | 389 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN | 390 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, 391 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR); 392 return 0; 393 } 394 #endif 395 396 static SIMPLE_DEV_PM_OPS(stmp3xxx_rtc_pm_ops, stmp3xxx_rtc_suspend, 397 stmp3xxx_rtc_resume); 398 399 static const struct of_device_id rtc_dt_ids[] = { 400 { .compatible = "fsl,stmp3xxx-rtc", }, 401 { /* sentinel */ } 402 }; 403 MODULE_DEVICE_TABLE(of, rtc_dt_ids); 404 405 static struct platform_driver stmp3xxx_rtcdrv = { 406 .probe = stmp3xxx_rtc_probe, 407 .remove = stmp3xxx_rtc_remove, 408 .driver = { 409 .name = "stmp3xxx-rtc", 410 .pm = &stmp3xxx_rtc_pm_ops, 411 .of_match_table = rtc_dt_ids, 412 }, 413 }; 414 415 module_platform_driver(stmp3xxx_rtcdrv); 416 417 MODULE_DESCRIPTION("STMP3xxx RTC Driver"); 418 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and " 419 "Wolfram Sang <w.sang@pengutronix.de>"); 420 MODULE_LICENSE("GPL"); 421