1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Motorola CPCAP PMIC RTC driver 4 * 5 * Based on cpcap-regulator.c from Motorola Linux kernel tree 6 * Copyright (C) 2009 Motorola, Inc. 7 * 8 * Rewritten for mainline kernel 9 * - use DT 10 * - use regmap 11 * - use standard interrupt framework 12 * - use managed device resources 13 * - remove custom "secure clock daemon" helpers 14 * 15 * Copyright (C) 2017 Sebastian Reichel <sre@kernel.org> 16 */ 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/mod_devicetable.h> 20 #include <linux/init.h> 21 #include <linux/device.h> 22 #include <linux/platform_device.h> 23 #include <linux/rtc.h> 24 #include <linux/err.h> 25 #include <linux/regmap.h> 26 #include <linux/mfd/motorola-cpcap.h> 27 #include <linux/slab.h> 28 #include <linux/sched.h> 29 30 #define SECS_PER_DAY 86400 31 #define DAY_MASK 0x7FFF 32 #define TOD1_MASK 0x00FF 33 #define TOD2_MASK 0x01FF 34 35 struct cpcap_time { 36 int day; 37 int tod1; 38 int tod2; 39 }; 40 41 struct cpcap_rtc { 42 struct regmap *regmap; 43 struct rtc_device *rtc_dev; 44 u16 vendor; 45 int alarm_irq; 46 bool alarm_enabled; 47 int update_irq; 48 bool update_enabled; 49 }; 50 51 static void cpcap2rtc_time(struct rtc_time *rtc, struct cpcap_time *cpcap) 52 { 53 unsigned long int tod; 54 unsigned long int time; 55 56 tod = (cpcap->tod1 & TOD1_MASK) | ((cpcap->tod2 & TOD2_MASK) << 8); 57 time = tod + ((cpcap->day & DAY_MASK) * SECS_PER_DAY); 58 59 rtc_time64_to_tm(time, rtc); 60 } 61 62 static void rtc2cpcap_time(struct cpcap_time *cpcap, struct rtc_time *rtc) 63 { 64 unsigned long time; 65 66 time = rtc_tm_to_time64(rtc); 67 68 cpcap->day = time / SECS_PER_DAY; 69 time %= SECS_PER_DAY; 70 cpcap->tod2 = (time >> 8) & TOD2_MASK; 71 cpcap->tod1 = time & TOD1_MASK; 72 } 73 74 static int cpcap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 75 { 76 struct cpcap_rtc *rtc = dev_get_drvdata(dev); 77 78 if (rtc->alarm_enabled == enabled) 79 return 0; 80 81 if (enabled) 82 enable_irq(rtc->alarm_irq); 83 else 84 disable_irq(rtc->alarm_irq); 85 86 rtc->alarm_enabled = !!enabled; 87 88 return 0; 89 } 90 91 static int cpcap_rtc_read_time(struct device *dev, struct rtc_time *tm) 92 { 93 struct cpcap_rtc *rtc; 94 struct cpcap_time cpcap_tm; 95 int temp_tod2; 96 int ret; 97 98 rtc = dev_get_drvdata(dev); 99 100 ret = regmap_read(rtc->regmap, CPCAP_REG_TOD2, &temp_tod2); 101 ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day); 102 ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD1, &cpcap_tm.tod1); 103 ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD2, &cpcap_tm.tod2); 104 105 if (temp_tod2 > cpcap_tm.tod2) 106 ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day); 107 108 if (ret) { 109 dev_err(dev, "Failed to read time\n"); 110 return -EIO; 111 } 112 113 cpcap2rtc_time(tm, &cpcap_tm); 114 115 return 0; 116 } 117 118 static int cpcap_rtc_set_time(struct device *dev, struct rtc_time *tm) 119 { 120 struct cpcap_rtc *rtc; 121 struct cpcap_time cpcap_tm; 122 int ret = 0; 123 124 rtc = dev_get_drvdata(dev); 125 126 rtc2cpcap_time(&cpcap_tm, tm); 127 128 if (rtc->alarm_enabled) 129 disable_irq(rtc->alarm_irq); 130 if (rtc->update_enabled) 131 disable_irq(rtc->update_irq); 132 133 if (rtc->vendor == CPCAP_VENDOR_ST) { 134 /* The TOD1 and TOD2 registers MUST be written in this order 135 * for the change to properly set. 136 */ 137 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1, 138 TOD1_MASK, cpcap_tm.tod1); 139 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2, 140 TOD2_MASK, cpcap_tm.tod2); 141 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY, 142 DAY_MASK, cpcap_tm.day); 143 } else { 144 /* Clearing the upper lower 8 bits of the TOD guarantees that 145 * the upper half of TOD (TOD2) will not increment for 0xFF RTC 146 * ticks (255 seconds). During this time we can safely write 147 * to DAY, TOD2, then TOD1 (in that order) and expect RTC to be 148 * synchronized to the exact time requested upon the final write 149 * to TOD1. 150 */ 151 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1, 152 TOD1_MASK, 0); 153 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY, 154 DAY_MASK, cpcap_tm.day); 155 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2, 156 TOD2_MASK, cpcap_tm.tod2); 157 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1, 158 TOD1_MASK, cpcap_tm.tod1); 159 } 160 161 if (rtc->update_enabled) 162 enable_irq(rtc->update_irq); 163 if (rtc->alarm_enabled) 164 enable_irq(rtc->alarm_irq); 165 166 return ret; 167 } 168 169 static int cpcap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 170 { 171 struct cpcap_rtc *rtc; 172 struct cpcap_time cpcap_tm; 173 int ret; 174 175 rtc = dev_get_drvdata(dev); 176 177 alrm->enabled = rtc->alarm_enabled; 178 179 ret = regmap_read(rtc->regmap, CPCAP_REG_DAYA, &cpcap_tm.day); 180 ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA2, &cpcap_tm.tod2); 181 ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA1, &cpcap_tm.tod1); 182 183 if (ret) { 184 dev_err(dev, "Failed to read time\n"); 185 return -EIO; 186 } 187 188 cpcap2rtc_time(&alrm->time, &cpcap_tm); 189 return rtc_valid_tm(&alrm->time); 190 } 191 192 static int cpcap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 193 { 194 struct cpcap_rtc *rtc; 195 struct cpcap_time cpcap_tm; 196 int ret; 197 198 rtc = dev_get_drvdata(dev); 199 200 rtc2cpcap_time(&cpcap_tm, &alrm->time); 201 202 if (rtc->alarm_enabled) 203 disable_irq(rtc->alarm_irq); 204 205 ret = regmap_update_bits(rtc->regmap, CPCAP_REG_DAYA, DAY_MASK, 206 cpcap_tm.day); 207 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA2, TOD2_MASK, 208 cpcap_tm.tod2); 209 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA1, TOD1_MASK, 210 cpcap_tm.tod1); 211 212 if (!ret) { 213 enable_irq(rtc->alarm_irq); 214 rtc->alarm_enabled = true; 215 } 216 217 return ret; 218 } 219 220 static const struct rtc_class_ops cpcap_rtc_ops = { 221 .read_time = cpcap_rtc_read_time, 222 .set_time = cpcap_rtc_set_time, 223 .read_alarm = cpcap_rtc_read_alarm, 224 .set_alarm = cpcap_rtc_set_alarm, 225 .alarm_irq_enable = cpcap_rtc_alarm_irq_enable, 226 }; 227 228 static irqreturn_t cpcap_rtc_alarm_irq(int irq, void *data) 229 { 230 struct cpcap_rtc *rtc = data; 231 232 rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF); 233 return IRQ_HANDLED; 234 } 235 236 static irqreturn_t cpcap_rtc_update_irq(int irq, void *data) 237 { 238 struct cpcap_rtc *rtc = data; 239 240 rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF); 241 return IRQ_HANDLED; 242 } 243 244 static int cpcap_rtc_probe(struct platform_device *pdev) 245 { 246 struct device *dev = &pdev->dev; 247 struct cpcap_rtc *rtc; 248 int err; 249 250 rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL); 251 if (!rtc) 252 return -ENOMEM; 253 254 rtc->regmap = dev_get_regmap(dev->parent, NULL); 255 if (!rtc->regmap) 256 return -ENODEV; 257 258 platform_set_drvdata(pdev, rtc); 259 rtc->rtc_dev = devm_rtc_allocate_device(dev); 260 if (IS_ERR(rtc->rtc_dev)) 261 return PTR_ERR(rtc->rtc_dev); 262 263 rtc->rtc_dev->ops = &cpcap_rtc_ops; 264 rtc->rtc_dev->range_max = (1 << 14) * SECS_PER_DAY - 1; 265 266 err = cpcap_get_vendor(dev, rtc->regmap, &rtc->vendor); 267 if (err) 268 return err; 269 270 rtc->alarm_irq = platform_get_irq(pdev, 0); 271 err = devm_request_threaded_irq(dev, rtc->alarm_irq, NULL, 272 cpcap_rtc_alarm_irq, IRQF_TRIGGER_NONE, 273 "rtc_alarm", rtc); 274 if (err) { 275 dev_err(dev, "Could not request alarm irq: %d\n", err); 276 return err; 277 } 278 disable_irq(rtc->alarm_irq); 279 280 /* Stock Android uses the 1 Hz interrupt for "secure clock daemon", 281 * which is not supported by the mainline kernel. The mainline kernel 282 * does not use the irq at the moment, but we explicitly request and 283 * disable it, so that its masked and does not wake up the processor 284 * every second. 285 */ 286 rtc->update_irq = platform_get_irq(pdev, 1); 287 err = devm_request_threaded_irq(dev, rtc->update_irq, NULL, 288 cpcap_rtc_update_irq, IRQF_TRIGGER_NONE, 289 "rtc_1hz", rtc); 290 if (err) { 291 dev_err(dev, "Could not request update irq: %d\n", err); 292 return err; 293 } 294 disable_irq(rtc->update_irq); 295 296 err = device_init_wakeup(dev, 1); 297 if (err) { 298 dev_err(dev, "wakeup initialization failed (%d)\n", err); 299 /* ignore error and continue without wakeup support */ 300 } 301 302 return rtc_register_device(rtc->rtc_dev); 303 } 304 305 static const struct of_device_id cpcap_rtc_of_match[] = { 306 { .compatible = "motorola,cpcap-rtc", }, 307 {}, 308 }; 309 MODULE_DEVICE_TABLE(of, cpcap_rtc_of_match); 310 311 static struct platform_driver cpcap_rtc_driver = { 312 .probe = cpcap_rtc_probe, 313 .driver = { 314 .name = "cpcap-rtc", 315 .of_match_table = cpcap_rtc_of_match, 316 }, 317 }; 318 319 module_platform_driver(cpcap_rtc_driver); 320 321 MODULE_ALIAS("platform:cpcap-rtc"); 322 MODULE_DESCRIPTION("CPCAP RTC driver"); 323 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>"); 324 MODULE_LICENSE("GPL"); 325