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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Real Time Clock driver for Marvell 88PM860x PMIC
0004  *
0005  * Copyright (c) 2010 Marvell International Ltd.
0006  * Author:  Haojian Zhuang <haojian.zhuang@marvell.com>
0007  */
0008 
0009 #include <linux/kernel.h>
0010 #include <linux/module.h>
0011 #include <linux/of.h>
0012 #include <linux/platform_device.h>
0013 #include <linux/slab.h>
0014 #include <linux/mutex.h>
0015 #include <linux/rtc.h>
0016 #include <linux/delay.h>
0017 #include <linux/mfd/core.h>
0018 #include <linux/mfd/88pm860x.h>
0019 
0020 #define VRTC_CALIBRATION
0021 
0022 struct pm860x_rtc_info {
0023     struct pm860x_chip  *chip;
0024     struct i2c_client   *i2c;
0025     struct rtc_device   *rtc_dev;
0026     struct device       *dev;
0027     struct delayed_work calib_work;
0028 
0029     int         irq;
0030     int         vrtc;
0031 };
0032 
0033 #define REG_VRTC_MEAS1      0x7D
0034 
0035 #define REG0_ADDR       0xB0
0036 #define REG1_ADDR       0xB2
0037 #define REG2_ADDR       0xB4
0038 #define REG3_ADDR       0xB6
0039 
0040 #define REG0_DATA       0xB1
0041 #define REG1_DATA       0xB3
0042 #define REG2_DATA       0xB5
0043 #define REG3_DATA       0xB7
0044 
0045 /* bit definitions of Measurement Enable Register 2 (0x51) */
0046 #define MEAS2_VRTC      (1 << 0)
0047 
0048 /* bit definitions of RTC Register 1 (0xA0) */
0049 #define ALARM_EN        (1 << 3)
0050 #define ALARM_WAKEUP        (1 << 4)
0051 #define ALARM           (1 << 5)
0052 #define RTC1_USE_XO     (1 << 7)
0053 
0054 #define VRTC_CALIB_INTERVAL (HZ * 60 * 10)      /* 10 minutes */
0055 
0056 static irqreturn_t rtc_update_handler(int irq, void *data)
0057 {
0058     struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
0059     int mask;
0060 
0061     mask = ALARM | ALARM_WAKEUP;
0062     pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
0063     rtc_update_irq(info->rtc_dev, 1, RTC_AF);
0064     return IRQ_HANDLED;
0065 }
0066 
0067 static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
0068 {
0069     struct pm860x_rtc_info *info = dev_get_drvdata(dev);
0070 
0071     if (enabled)
0072         pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
0073     else
0074         pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
0075     return 0;
0076 }
0077 
0078 static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
0079 {
0080     struct pm860x_rtc_info *info = dev_get_drvdata(dev);
0081     unsigned char buf[8];
0082     unsigned long ticks, base, data;
0083 
0084     pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
0085     dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
0086         buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
0087     base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
0088         (buf[5] << 8) | buf[7];
0089 
0090     /* load 32-bit read-only counter */
0091     pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
0092     data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
0093         (buf[1] << 8) | buf[0];
0094     ticks = base + data;
0095     dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
0096         base, data, ticks);
0097 
0098     rtc_time64_to_tm(ticks, tm);
0099 
0100     return 0;
0101 }
0102 
0103 static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
0104 {
0105     struct pm860x_rtc_info *info = dev_get_drvdata(dev);
0106     unsigned char buf[4];
0107     unsigned long ticks, base, data;
0108 
0109     ticks = rtc_tm_to_time64(tm);
0110 
0111     /* load 32-bit read-only counter */
0112     pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
0113     data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
0114         (buf[1] << 8) | buf[0];
0115     base = ticks - data;
0116     dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
0117         base, data, ticks);
0118 
0119     pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
0120     pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
0121     pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
0122     pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
0123 
0124     return 0;
0125 }
0126 
0127 static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
0128 {
0129     struct pm860x_rtc_info *info = dev_get_drvdata(dev);
0130     unsigned char buf[8];
0131     unsigned long ticks, base, data;
0132     int ret;
0133 
0134     pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
0135     dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
0136         buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
0137     base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
0138         (buf[5] << 8) | buf[7];
0139 
0140     pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
0141     data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
0142         (buf[1] << 8) | buf[0];
0143     ticks = base + data;
0144     dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
0145         base, data, ticks);
0146 
0147     rtc_time64_to_tm(ticks, &alrm->time);
0148     ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
0149     alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
0150     alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
0151     return 0;
0152 }
0153 
0154 static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
0155 {
0156     struct pm860x_rtc_info *info = dev_get_drvdata(dev);
0157     unsigned long ticks, base, data;
0158     unsigned char buf[8];
0159     int mask;
0160 
0161     pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
0162 
0163     pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
0164     dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
0165         buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
0166     base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
0167         (buf[5] << 8) | buf[7];
0168 
0169     ticks = rtc_tm_to_time64(&alrm->time);
0170     data = ticks - base;
0171 
0172     buf[0] = data & 0xff;
0173     buf[1] = (data >> 8) & 0xff;
0174     buf[2] = (data >> 16) & 0xff;
0175     buf[3] = (data >> 24) & 0xff;
0176     pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
0177     if (alrm->enabled) {
0178         mask = ALARM | ALARM_WAKEUP | ALARM_EN;
0179         pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
0180     } else {
0181         mask = ALARM | ALARM_WAKEUP | ALARM_EN;
0182         pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
0183                 ALARM | ALARM_WAKEUP);
0184     }
0185     return 0;
0186 }
0187 
0188 static const struct rtc_class_ops pm860x_rtc_ops = {
0189     .read_time  = pm860x_rtc_read_time,
0190     .set_time   = pm860x_rtc_set_time,
0191     .read_alarm = pm860x_rtc_read_alarm,
0192     .set_alarm  = pm860x_rtc_set_alarm,
0193     .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
0194 };
0195 
0196 #ifdef VRTC_CALIBRATION
0197 static void calibrate_vrtc_work(struct work_struct *work)
0198 {
0199     struct pm860x_rtc_info *info = container_of(work,
0200         struct pm860x_rtc_info, calib_work.work);
0201     unsigned char buf[2];
0202     unsigned int sum, data, mean, vrtc_set;
0203     int i;
0204 
0205     for (i = 0, sum = 0; i < 16; i++) {
0206         msleep(100);
0207         pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
0208         data = (buf[0] << 4) | buf[1];
0209         data = (data * 5400) >> 12; /* convert to mv */
0210         sum += data;
0211     }
0212     mean = sum >> 4;
0213     vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
0214     dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
0215 
0216     sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
0217     data = sum & 0x3;
0218     if ((mean + 200) < vrtc_set) {
0219         /* try higher voltage */
0220         if (++data == 4)
0221             goto out;
0222         data = (sum & 0xf8) | (data & 0x3);
0223         pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
0224     } else if ((mean - 200) > vrtc_set) {
0225         /* try lower voltage */
0226         if (data-- == 0)
0227             goto out;
0228         data = (sum & 0xf8) | (data & 0x3);
0229         pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
0230     } else
0231         goto out;
0232     dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
0233     /* trigger next calibration since VRTC is updated */
0234     schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
0235     return;
0236 out:
0237     /* disable measurement */
0238     pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
0239     dev_dbg(info->dev, "finish VRTC calibration\n");
0240     return;
0241 }
0242 #endif
0243 
0244 #ifdef CONFIG_OF
0245 static int pm860x_rtc_dt_init(struct platform_device *pdev,
0246                   struct pm860x_rtc_info *info)
0247 {
0248     struct device_node *np = pdev->dev.parent->of_node;
0249     int ret;
0250     if (!np)
0251         return -ENODEV;
0252     np = of_get_child_by_name(np, "rtc");
0253     if (!np) {
0254         dev_err(&pdev->dev, "failed to find rtc node\n");
0255         return -ENODEV;
0256     }
0257     ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
0258     if (ret)
0259         info->vrtc = 0;
0260     of_node_put(np);
0261     return 0;
0262 }
0263 #else
0264 #define pm860x_rtc_dt_init(x, y)    do { } while (0)
0265 #endif
0266 
0267 static int pm860x_rtc_probe(struct platform_device *pdev)
0268 {
0269     struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
0270     struct pm860x_rtc_info *info;
0271     int ret;
0272 
0273     info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
0274                 GFP_KERNEL);
0275     if (!info)
0276         return -ENOMEM;
0277     info->irq = platform_get_irq(pdev, 0);
0278     if (info->irq < 0)
0279         return info->irq;
0280 
0281     info->chip = chip;
0282     info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
0283     info->dev = &pdev->dev;
0284     dev_set_drvdata(&pdev->dev, info);
0285 
0286     info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
0287     if (IS_ERR(info->rtc_dev))
0288         return PTR_ERR(info->rtc_dev);
0289 
0290     ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
0291                     rtc_update_handler, IRQF_ONESHOT, "rtc",
0292                     info);
0293     if (ret < 0) {
0294         dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
0295             info->irq, ret);
0296         return ret;
0297     }
0298 
0299     /* set addresses of 32-bit base value for RTC time */
0300     pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
0301     pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
0302     pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
0303     pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
0304 
0305     pm860x_rtc_dt_init(pdev, info);
0306 
0307     info->rtc_dev->ops = &pm860x_rtc_ops;
0308     info->rtc_dev->range_max = U32_MAX;
0309 
0310     ret = devm_rtc_register_device(info->rtc_dev);
0311     if (ret)
0312         return ret;
0313 
0314     /*
0315      * enable internal XO instead of internal 3.25MHz clock since it can
0316      * free running in PMIC power-down state.
0317      */
0318     pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
0319 
0320 #ifdef VRTC_CALIBRATION
0321     /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
0322     pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
0323 
0324     /* calibrate VRTC */
0325     INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
0326     schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
0327 #endif  /* VRTC_CALIBRATION */
0328 
0329     device_init_wakeup(&pdev->dev, 1);
0330 
0331     return 0;
0332 }
0333 
0334 static int pm860x_rtc_remove(struct platform_device *pdev)
0335 {
0336     struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
0337 
0338 #ifdef VRTC_CALIBRATION
0339     cancel_delayed_work_sync(&info->calib_work);
0340     /* disable measurement */
0341     pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
0342 #endif  /* VRTC_CALIBRATION */
0343 
0344     return 0;
0345 }
0346 
0347 #ifdef CONFIG_PM_SLEEP
0348 static int pm860x_rtc_suspend(struct device *dev)
0349 {
0350     struct platform_device *pdev = to_platform_device(dev);
0351     struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
0352 
0353     if (device_may_wakeup(dev))
0354         chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
0355     return 0;
0356 }
0357 static int pm860x_rtc_resume(struct device *dev)
0358 {
0359     struct platform_device *pdev = to_platform_device(dev);
0360     struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
0361 
0362     if (device_may_wakeup(dev))
0363         chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
0364     return 0;
0365 }
0366 #endif
0367 
0368 static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
0369 
0370 static struct platform_driver pm860x_rtc_driver = {
0371     .driver     = {
0372         .name   = "88pm860x-rtc",
0373         .pm = &pm860x_rtc_pm_ops,
0374     },
0375     .probe      = pm860x_rtc_probe,
0376     .remove     = pm860x_rtc_remove,
0377 };
0378 
0379 module_platform_driver(pm860x_rtc_driver);
0380 
0381 MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
0382 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
0383 MODULE_LICENSE("GPL");
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