LXR linux/drivers/rtc/rtc-cpcap.c

   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
  35struct cpcap_time {
  36        int day;
  37        int tod1;
  38        int tod2;
  39};
  40
  41struct 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
  51static 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_time_to_tm(time, rtc);
  60}
  61
  62static void rtc2cpcap_time(struct cpcap_time *cpcap, struct rtc_time *rtc)
  63{
  64        unsigned long time;
  65
  66        rtc_tm_to_time(rtc, &time);
  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
  74static 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
  91static 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
 118static 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
 169static 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
 192static 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
 220static 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
 228static 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
 236static 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
 244static 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_device_register(dev, "cpcap_rtc",
 260                                                &cpcap_rtc_ops, THIS_MODULE);
 261
 262        if (IS_ERR(rtc->rtc_dev))
 263                return PTR_ERR(rtc->rtc_dev);
 264
 265        err = cpcap_get_vendor(dev, rtc->regmap, &rtc->vendor);
 266        if (err)
 267                return err;
 268
 269        rtc->alarm_irq = platform_get_irq(pdev, 0);
 270        err = devm_request_threaded_irq(dev, rtc->alarm_irq, NULL,
 271                                        cpcap_rtc_alarm_irq, IRQF_TRIGGER_NONE,
 272                                        "rtc_alarm", rtc);
 273        if (err) {
 274                dev_err(dev, "Could not request alarm irq: %d\n", err);
 275                return err;
 276        }
 277        disable_irq(rtc->alarm_irq);
 278
 279        /* Stock Android uses the 1 Hz interrupt for "secure clock daemon",
 280         * which is not supported by the mainline kernel. The mainline kernel
 281         * does not use the irq at the moment, but we explicitly request and
 282         * disable it, so that its masked and does not wake up the processor
 283         * every second.
 284         */
 285        rtc->update_irq = platform_get_irq(pdev, 1);
 286        err = devm_request_threaded_irq(dev, rtc->update_irq, NULL,
 287                                        cpcap_rtc_update_irq, IRQF_TRIGGER_NONE,
 288                                        "rtc_1hz", rtc);
 289        if (err) {
 290                dev_err(dev, "Could not request update irq: %d\n", err);
 291                return err;
 292        }
 293        disable_irq(rtc->update_irq);
 294
 295        err = device_init_wakeup(dev, 1);
 296        if (err) {
 297                dev_err(dev, "wakeup initialization failed (%d)\n", err);
 298                /* ignore error and continue without wakeup support */
 299        }
 300
 301        return 0;
 302}
 303
 304static const struct of_device_id cpcap_rtc_of_match[] = {
 305        { .compatible = "motorola,cpcap-rtc", },
 306        {},
 307};
 308MODULE_DEVICE_TABLE(of, cpcap_rtc_of_match);
 309
 310static struct platform_driver cpcap_rtc_driver = {
 311        .probe          = cpcap_rtc_probe,
 312        .driver         = {
 313                .name   = "cpcap-rtc",
 314                .of_match_table = cpcap_rtc_of_match,
 315        },
 316};
 317
 318module_platform_driver(cpcap_rtc_driver);
 319
 320MODULE_ALIAS("platform:cpcap-rtc");
 321MODULE_DESCRIPTION("CPCAP RTC driver");
 322MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
 323MODULE_LICENSE("GPL");
 324