linux/drivers/rtc/rtc-palmas.c
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   1/*
   2 * rtc-palmas.c -- Palmas Real Time Clock driver.
   3
   4 * RTC driver for TI Palma series devices like TPS65913,
   5 * TPS65914 power management IC.
   6 *
   7 * Copyright (c) 2012, NVIDIA Corporation.
   8 *
   9 * Author: Laxman Dewangan <ldewangan@nvidia.com>
  10 *
  11 * This program is free software; you can redistribute it and/or
  12 * modify it under the terms of the GNU General Public License as
  13 * published by the Free Software Foundation version 2.
  14 *
  15 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
  16 * whether express or implied; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18 * General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  23 * 02111-1307, USA
  24 */
  25
  26#include <linux/bcd.h>
  27#include <linux/errno.h>
  28#include <linux/init.h>
  29#include <linux/interrupt.h>
  30#include <linux/kernel.h>
  31#include <linux/mfd/palmas.h>
  32#include <linux/module.h>
  33#include <linux/of.h>
  34#include <linux/rtc.h>
  35#include <linux/types.h>
  36#include <linux/platform_device.h>
  37#include <linux/pm.h>
  38
  39struct palmas_rtc {
  40        struct rtc_device       *rtc;
  41        struct device           *dev;
  42        unsigned int            irq;
  43};
  44
  45/* Total number of RTC registers needed to set time*/
  46#define PALMAS_NUM_TIME_REGS    (PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
  47
  48static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
  49{
  50        unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
  51        struct palmas *palmas = dev_get_drvdata(dev->parent);
  52        int ret;
  53
  54        /* Copy RTC counting registers to static registers or latches */
  55        ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
  56                PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
  57        if (ret < 0) {
  58                dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret);
  59                return ret;
  60        }
  61
  62        ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
  63                        rtc_data, PALMAS_NUM_TIME_REGS);
  64        if (ret < 0) {
  65                dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret);
  66                return ret;
  67        }
  68
  69        tm->tm_sec = bcd2bin(rtc_data[0]);
  70        tm->tm_min = bcd2bin(rtc_data[1]);
  71        tm->tm_hour = bcd2bin(rtc_data[2]);
  72        tm->tm_mday = bcd2bin(rtc_data[3]);
  73        tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
  74        tm->tm_year = bcd2bin(rtc_data[5]) + 100;
  75
  76        return ret;
  77}
  78
  79static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
  80{
  81        unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
  82        struct palmas *palmas = dev_get_drvdata(dev->parent);
  83        int ret;
  84
  85        rtc_data[0] = bin2bcd(tm->tm_sec);
  86        rtc_data[1] = bin2bcd(tm->tm_min);
  87        rtc_data[2] = bin2bcd(tm->tm_hour);
  88        rtc_data[3] = bin2bcd(tm->tm_mday);
  89        rtc_data[4] = bin2bcd(tm->tm_mon + 1);
  90        rtc_data[5] = bin2bcd(tm->tm_year - 100);
  91
  92        /* Stop RTC while updating the RTC time registers */
  93        ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
  94                PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
  95        if (ret < 0) {
  96                dev_err(dev, "RTC stop failed, err = %d\n", ret);
  97                return ret;
  98        }
  99
 100        ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
 101                rtc_data, PALMAS_NUM_TIME_REGS);
 102        if (ret < 0) {
 103                dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret);
 104                return ret;
 105        }
 106
 107        /* Start back RTC */
 108        ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
 109                PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC);
 110        if (ret < 0)
 111                dev_err(dev, "RTC start failed, err = %d\n", ret);
 112        return ret;
 113}
 114
 115static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
 116{
 117        struct palmas *palmas = dev_get_drvdata(dev->parent);
 118        u8 val;
 119
 120        val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0;
 121        return palmas_write(palmas, PALMAS_RTC_BASE,
 122                PALMAS_RTC_INTERRUPTS_REG, val);
 123}
 124
 125static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 126{
 127        unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
 128        u32 int_val;
 129        struct palmas *palmas = dev_get_drvdata(dev->parent);
 130        int ret;
 131
 132        ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE,
 133                        PALMAS_ALARM_SECONDS_REG,
 134                        alarm_data, PALMAS_NUM_TIME_REGS);
 135        if (ret < 0) {
 136                dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret);
 137                return ret;
 138        }
 139
 140        alm->time.tm_sec = bcd2bin(alarm_data[0]);
 141        alm->time.tm_min = bcd2bin(alarm_data[1]);
 142        alm->time.tm_hour = bcd2bin(alarm_data[2]);
 143        alm->time.tm_mday = bcd2bin(alarm_data[3]);
 144        alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
 145        alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
 146
 147        ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
 148                        &int_val);
 149        if (ret < 0) {
 150                dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret);
 151                return ret;
 152        }
 153
 154        if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
 155                alm->enabled = 1;
 156        return ret;
 157}
 158
 159static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 160{
 161        unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
 162        struct palmas *palmas = dev_get_drvdata(dev->parent);
 163        int ret;
 164
 165        ret = palmas_rtc_alarm_irq_enable(dev, 0);
 166        if (ret < 0) {
 167                dev_err(dev, "Disable RTC alarm failed\n");
 168                return ret;
 169        }
 170
 171        alarm_data[0] = bin2bcd(alm->time.tm_sec);
 172        alarm_data[1] = bin2bcd(alm->time.tm_min);
 173        alarm_data[2] = bin2bcd(alm->time.tm_hour);
 174        alarm_data[3] = bin2bcd(alm->time.tm_mday);
 175        alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
 176        alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
 177
 178        ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
 179                PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);
 180        if (ret < 0) {
 181                dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret);
 182                return ret;
 183        }
 184
 185        if (alm->enabled)
 186                ret = palmas_rtc_alarm_irq_enable(dev, 1);
 187        return ret;
 188}
 189
 190static int palmas_clear_interrupts(struct device *dev)
 191{
 192        struct palmas *palmas = dev_get_drvdata(dev->parent);
 193        unsigned int rtc_reg;
 194        int ret;
 195
 196        ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
 197                                &rtc_reg);
 198        if (ret < 0) {
 199                dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret);
 200                return ret;
 201        }
 202
 203        ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
 204                        rtc_reg);
 205        if (ret < 0) {
 206                dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret);
 207                return ret;
 208        }
 209        return 0;
 210}
 211
 212static irqreturn_t palmas_rtc_interrupt(int irq, void *context)
 213{
 214        struct palmas_rtc *palmas_rtc = context;
 215        struct device *dev = palmas_rtc->dev;
 216        int ret;
 217
 218        ret = palmas_clear_interrupts(dev);
 219        if (ret < 0) {
 220                dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret);
 221                return IRQ_NONE;
 222        }
 223
 224        rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 225        return IRQ_HANDLED;
 226}
 227
 228static struct rtc_class_ops palmas_rtc_ops = {
 229        .read_time      = palmas_rtc_read_time,
 230        .set_time       = palmas_rtc_set_time,
 231        .read_alarm     = palmas_rtc_read_alarm,
 232        .set_alarm      = palmas_rtc_set_alarm,
 233        .alarm_irq_enable = palmas_rtc_alarm_irq_enable,
 234};
 235
 236static int palmas_rtc_probe(struct platform_device *pdev)
 237{
 238        struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
 239        struct palmas_rtc *palmas_rtc = NULL;
 240        int ret;
 241        bool enable_bb_charging = false;
 242        bool high_bb_charging;
 243
 244        if (pdev->dev.of_node) {
 245                enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
 246                                        "ti,backup-battery-chargeable");
 247                high_bb_charging = of_property_read_bool(pdev->dev.of_node,
 248                                        "ti,backup-battery-charge-high-current");
 249        }
 250
 251        palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
 252                        GFP_KERNEL);
 253        if (!palmas_rtc)
 254                return -ENOMEM;
 255
 256        /* Clear pending interrupts */
 257        ret = palmas_clear_interrupts(&pdev->dev);
 258        if (ret < 0) {
 259                dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret);
 260                return ret;
 261        }
 262
 263        palmas_rtc->dev = &pdev->dev;
 264        platform_set_drvdata(pdev, palmas_rtc);
 265
 266        if (enable_bb_charging) {
 267                unsigned reg = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
 268
 269                if (high_bb_charging)
 270                        reg = 0;
 271
 272                ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
 273                        PALMAS_BACKUP_BATTERY_CTRL,
 274                        PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
 275                if (ret < 0) {
 276                        dev_err(&pdev->dev,
 277                                "BACKUP_BATTERY_CTRL update failed, %d\n", ret);
 278                        return ret;
 279                }
 280
 281                ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
 282                        PALMAS_BACKUP_BATTERY_CTRL,
 283                        PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
 284                        PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
 285                if (ret < 0) {
 286                        dev_err(&pdev->dev,
 287                                "BACKUP_BATTERY_CTRL update failed, %d\n", ret);
 288                        return ret;
 289                }
 290        }
 291
 292        /* Start RTC */
 293        ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
 294                        PALMAS_RTC_CTRL_REG_STOP_RTC,
 295                        PALMAS_RTC_CTRL_REG_STOP_RTC);
 296        if (ret < 0) {
 297                dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret);
 298                return ret;
 299        }
 300
 301        palmas_rtc->irq = platform_get_irq(pdev, 0);
 302
 303        device_init_wakeup(&pdev->dev, 1);
 304        palmas_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 305                                &palmas_rtc_ops, THIS_MODULE);
 306        if (IS_ERR(palmas_rtc->rtc)) {
 307                ret = PTR_ERR(palmas_rtc->rtc);
 308                dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret);
 309                return ret;
 310        }
 311
 312        ret = devm_request_threaded_irq(&pdev->dev, palmas_rtc->irq, NULL,
 313                        palmas_rtc_interrupt,
 314                        IRQF_TRIGGER_LOW | IRQF_ONESHOT |
 315                        IRQF_EARLY_RESUME,
 316                        dev_name(&pdev->dev), palmas_rtc);
 317        if (ret < 0) {
 318                dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret);
 319                return ret;
 320        }
 321
 322        return 0;
 323}
 324
 325static int palmas_rtc_remove(struct platform_device *pdev)
 326{
 327        palmas_rtc_alarm_irq_enable(&pdev->dev, 0);
 328        return 0;
 329}
 330
 331#ifdef CONFIG_PM_SLEEP
 332static int palmas_rtc_suspend(struct device *dev)
 333{
 334        struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
 335
 336        if (device_may_wakeup(dev))
 337                enable_irq_wake(palmas_rtc->irq);
 338        return 0;
 339}
 340
 341static int palmas_rtc_resume(struct device *dev)
 342{
 343        struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
 344
 345        if (device_may_wakeup(dev))
 346                disable_irq_wake(palmas_rtc->irq);
 347        return 0;
 348}
 349#endif
 350
 351static const struct dev_pm_ops palmas_rtc_pm_ops = {
 352        SET_SYSTEM_SLEEP_PM_OPS(palmas_rtc_suspend, palmas_rtc_resume)
 353};
 354
 355#ifdef CONFIG_OF
 356static struct of_device_id of_palmas_rtc_match[] = {
 357        { .compatible = "ti,palmas-rtc"},
 358        { },
 359};
 360MODULE_DEVICE_TABLE(of, of_palmas_rtc_match);
 361#endif
 362
 363static struct platform_driver palmas_rtc_driver = {
 364        .probe          = palmas_rtc_probe,
 365        .remove         = palmas_rtc_remove,
 366        .driver         = {
 367                .owner  = THIS_MODULE,
 368                .name   = "palmas-rtc",
 369                .pm     = &palmas_rtc_pm_ops,
 370                .of_match_table = of_match_ptr(of_palmas_rtc_match),
 371        },
 372};
 373
 374module_platform_driver(palmas_rtc_driver);
 375
 376MODULE_ALIAS("platform:palmas_rtc");
 377MODULE_DESCRIPTION("TI PALMAS series RTC driver");
 378MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 379MODULE_LICENSE("GPL v2");
 380
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