// SPDX-License-Identifier: GPL-2.0-only
/*
 * An I2C and SPI driver for the NXP PCF2127/29 RTC
 * Copyright 2013 Til-Technologies
 *
 * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
 *
 * Watchdog and tamper functions
 * Author: Bruno Thomsen <bruno.thomsen@gmail.com>
 *
 * based on the other drivers in this same directory.
 *
 * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf
 */

#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>

/* Control register 1 */
#define PCF2127_REG_CTRL1               0x00
#define PCF2127_BIT_CTRL1_TSF1                  BIT(4)
/* Control register 2 */
#define PCF2127_REG_CTRL2               0x01
#define PCF2127_BIT_CTRL2_TSIE                  BIT(2)
#define PCF2127_BIT_CTRL2_TSF2                  BIT(5)
/* Control register 3 */
#define PCF2127_REG_CTRL3               0x02
#define PCF2127_BIT_CTRL3_BLIE                  BIT(0)
#define PCF2127_BIT_CTRL3_BIE                   BIT(1)
#define PCF2127_BIT_CTRL3_BLF                   BIT(2)
#define PCF2127_BIT_CTRL3_BF                    BIT(3)
#define PCF2127_BIT_CTRL3_BTSE                  BIT(4)
/* Time and date registers */
#define PCF2127_REG_SC                  0x03
#define PCF2127_BIT_SC_OSF                      BIT(7)
#define PCF2127_REG_MN                  0x04
#define PCF2127_REG_HR                  0x05
#define PCF2127_REG_DM                  0x06
#define PCF2127_REG_DW                  0x07
#define PCF2127_REG_MO                  0x08
#define PCF2127_REG_YR                  0x09
/* Watchdog registers */
#define PCF2127_REG_WD_CTL              0x10
#define PCF2127_BIT_WD_CTL_TF0                  BIT(0)
#define PCF2127_BIT_WD_CTL_TF1                  BIT(1)
#define PCF2127_BIT_WD_CTL_CD0                  BIT(6)
#define PCF2127_BIT_WD_CTL_CD1                  BIT(7)
#define PCF2127_REG_WD_VAL              0x11
/* Tamper timestamp registers */
#define PCF2127_REG_TS_CTRL             0x12
#define PCF2127_BIT_TS_CTRL_TSOFF               BIT(6)
#define PCF2127_BIT_TS_CTRL_TSM                 BIT(7)
#define PCF2127_REG_TS_SC               0x13
#define PCF2127_REG_TS_MN               0x14
#define PCF2127_REG_TS_HR               0x15
#define PCF2127_REG_TS_DM               0x16
#define PCF2127_REG_TS_MO               0x17
#define PCF2127_REG_TS_YR               0x18
/*
 * RAM registers
 * PCF2127 has 512 bytes general-purpose static RAM (SRAM) that is
 * battery backed and can survive a power outage.
 * PCF2129 doesn't have this feature.
 */
#define PCF2127_REG_RAM_ADDR_MSB        0x1A
#define PCF2127_REG_RAM_WRT_CMD         0x1C
#define PCF2127_REG_RAM_RD_CMD          0x1D

/* Watchdog timer value constants */
#define PCF2127_WD_VAL_STOP             0
#define PCF2127_WD_VAL_MIN              2
#define PCF2127_WD_VAL_MAX              255
#define PCF2127_WD_VAL_DEFAULT          60

struct pcf2127 {
        struct rtc_device *rtc;
        struct watchdog_device wdd;
        struct regmap *regmap;
};

/*
 * In the routines that deal directly with the pcf2127 hardware, we use
 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 */
static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
        struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
        unsigned char buf[10];
        int ret;

        /*
         * Avoid reading CTRL2 register as it causes WD_VAL register
         * value to reset to 0 which means watchdog is stopped.
         */
        ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL3,
                               (buf + PCF2127_REG_CTRL3),
                               ARRAY_SIZE(buf) - PCF2127_REG_CTRL3);
        if (ret) {
                dev_err(dev, "%s: read error\n", __func__);
                return ret;
        }

        if (buf[PCF2127_REG_CTRL3] & PCF2127_BIT_CTRL3_BLF)
                dev_info(dev,
                        "low voltage detected, check/replace RTC battery.\n");

        /* Clock integrity is not guaranteed when OSF flag is set. */
        if (buf[PCF2127_REG_SC] & PCF2127_BIT_SC_OSF) {
                /*
                 * no need clear the flag here,
                 * it will be cleared once the new date is saved
                 */
                dev_warn(dev,
                         "oscillator stop detected, date/time is not reliable\n");
                return -EINVAL;
        }

        dev_dbg(dev,
                "%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, "
                "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
                __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
                buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
                buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
                buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);

        tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
        tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
        tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
        tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
        tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
        tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
        tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
        if (tm->tm_year < 70)
                tm->tm_year += 100;     /* assume we are in 1970...2069 */

        dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
                "mday=%d, mon=%d, year=%d, wday=%d\n",
                __func__,
                tm->tm_sec, tm->tm_min, tm->tm_hour,
                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

        return 0;
}

static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
        struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
        unsigned char buf[7];
        int i = 0, err;

        dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
                "mday=%d, mon=%d, year=%d, wday=%d\n",
                __func__,
                tm->tm_sec, tm->tm_min, tm->tm_hour,
                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

        /* hours, minutes and seconds */
        buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
        buf[i++] = bin2bcd(tm->tm_min);
        buf[i++] = bin2bcd(tm->tm_hour);
        buf[i++] = bin2bcd(tm->tm_mday);
        buf[i++] = tm->tm_wday & 0x07;

        /* month, 1 - 12 */
        buf[i++] = bin2bcd(tm->tm_mon + 1);

        /* year */
        buf[i++] = bin2bcd(tm->tm_year % 100);

        /* write register's data */
        err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
        if (err) {
                dev_err(dev,
                        "%s: err=%d", __func__, err);
                return err;
        }

        return 0;
}

#ifdef CONFIG_RTC_INTF_DEV
static int pcf2127_rtc_ioctl(struct device *dev,
                                unsigned int cmd, unsigned long arg)
{
        struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
        int touser;
        int ret;

        switch (cmd) {
        case RTC_VL_READ:
                ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
                if (ret)
                        return ret;

                touser = touser & PCF2127_BIT_CTRL3_BLF ? RTC_VL_BACKUP_LOW : 0;

                return put_user(touser, (unsigned int __user *)arg);
        default:
                return -ENOIOCTLCMD;
        }
}
#else
#define pcf2127_rtc_ioctl NULL
#endif

static const struct rtc_class_ops pcf2127_rtc_ops = {
        .ioctl          = pcf2127_rtc_ioctl,
        .read_time      = pcf2127_rtc_read_time,
        .set_time       = pcf2127_rtc_set_time,
};

static int pcf2127_nvmem_read(void *priv, unsigned int offset,
                              void *val, size_t bytes)
{
        struct pcf2127 *pcf2127 = priv;
        int ret;
        unsigned char offsetbuf[] = { offset >> 8, offset };

        ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
                                offsetbuf, 2);
        if (ret)
                return ret;

        ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
                               val, bytes);

        return ret ?: bytes;
}

static int pcf2127_nvmem_write(void *priv, unsigned int offset,
                               void *val, size_t bytes)
{
        struct pcf2127 *pcf2127 = priv;
        int ret;
        unsigned char offsetbuf[] = { offset >> 8, offset };

        ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
                                offsetbuf, 2);
        if (ret)
                return ret;

        ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
                                val, bytes);

        return ret ?: bytes;
}

/* watchdog driver */

static int pcf2127_wdt_ping(struct watchdog_device *wdd)
{
        struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);

        return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL, wdd->timeout);
}

/*
 * Restart watchdog timer if feature is active.
 *
 * Note: Reading CTRL2 register causes watchdog to stop which is unfortunate,
 * since register also contain control/status flags for other features.
 * Always call this function after reading CTRL2 register.
 */
static int pcf2127_wdt_active_ping(struct watchdog_device *wdd)
{
        int ret = 0;

        if (watchdog_active(wdd)) {
                ret = pcf2127_wdt_ping(wdd);
                if (ret)
                        dev_err(wdd->parent,
                                "%s: watchdog restart failed, ret=%d\n",
                                __func__, ret);
        }

        return ret;
}

static int pcf2127_wdt_start(struct watchdog_device *wdd)
{
        return pcf2127_wdt_ping(wdd);
}

static int pcf2127_wdt_stop(struct watchdog_device *wdd)
{
        struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);

        return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL,
                            PCF2127_WD_VAL_STOP);
}

static int pcf2127_wdt_set_timeout(struct watchdog_device *wdd,
                                   unsigned int new_timeout)
{
        dev_dbg(wdd->parent, "new watchdog timeout: %is (old: %is)\n",
                new_timeout, wdd->timeout);

        wdd->timeout = new_timeout;

        return pcf2127_wdt_active_ping(wdd);
}

static const struct watchdog_info pcf2127_wdt_info = {
        .identity = "NXP PCF2127/PCF2129 Watchdog",
        .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
};

static const struct watchdog_ops pcf2127_watchdog_ops = {
        .owner = THIS_MODULE,
        .start = pcf2127_wdt_start,
        .stop = pcf2127_wdt_stop,
        .ping = pcf2127_wdt_ping,
        .set_timeout = pcf2127_wdt_set_timeout,
};

/* sysfs interface */

static ssize_t timestamp0_store(struct device *dev,
                                struct device_attribute *attr,
                                const char *buf, size_t count)
{
        struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
        int ret;

        ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
                                 PCF2127_BIT_CTRL1_TSF1, 0);
        if (ret) {
                dev_err(dev, "%s: update ctrl1 ret=%d\n", __func__, ret);
                return ret;
        }

        ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
                                 PCF2127_BIT_CTRL2_TSF2, 0);
        if (ret) {
                dev_err(dev, "%s: update ctrl2 ret=%d\n", __func__, ret);
                return ret;
        }

        ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
        if (ret)
                return ret;

        return count;
};

static ssize_t timestamp0_show(struct device *dev,
                               struct device_attribute *attr, char *buf)
{
        struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
        struct rtc_time tm;
        int ret;
        unsigned char data[25];

        ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL1, data,
                               sizeof(data));
        if (ret) {
                dev_err(dev, "%s: read error ret=%d\n", __func__, ret);
                return ret;
        }

        dev_dbg(dev,
                "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, ts_sc=%02x, "
                "ts_mn=%02x, ts_hr=%02x, ts_dm=%02x, ts_mo=%02x, ts_yr=%02x\n",
                __func__, data[PCF2127_REG_CTRL1], data[PCF2127_REG_CTRL2],
                data[PCF2127_REG_CTRL3], data[PCF2127_REG_TS_SC],
                data[PCF2127_REG_TS_MN], data[PCF2127_REG_TS_HR],
                data[PCF2127_REG_TS_DM], data[PCF2127_REG_TS_MO],
                data[PCF2127_REG_TS_YR]);

        ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
        if (ret)
                return ret;

        if (!(data[PCF2127_REG_CTRL1] & PCF2127_BIT_CTRL1_TSF1) &&
            !(data[PCF2127_REG_CTRL2] & PCF2127_BIT_CTRL2_TSF2))
                return 0;

        tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
        tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
        tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);
        tm.tm_mday = bcd2bin(data[PCF2127_REG_TS_DM] & 0x3F);
        /* TS_MO register (month) value range: 1-12 */
        tm.tm_mon = bcd2bin(data[PCF2127_REG_TS_MO] & 0x1F) - 1;
        tm.tm_year = bcd2bin(data[PCF2127_REG_TS_YR]);
        if (tm.tm_year < 70)
                tm.tm_year += 100; /* assume we are in 1970...2069 */

        ret = rtc_valid_tm(&tm);
        if (ret)
                return ret;

        return sprintf(buf, "%llu\n",
                       (unsigned long long)rtc_tm_to_time64(&tm));
};

static DEVICE_ATTR_RW(timestamp0);

static struct attribute *pcf2127_attrs[] = {
        &dev_attr_timestamp0.attr,
        NULL
};

static const struct attribute_group pcf2127_attr_group = {
        .attrs  = pcf2127_attrs,
};

static int pcf2127_probe(struct device *dev, struct regmap *regmap,
                        const char *name, bool has_nvmem)
{
        struct pcf2127 *pcf2127;
        u32 wdd_timeout;
        int ret = 0;

        dev_dbg(dev, "%s\n", __func__);

        pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
        if (!pcf2127)
                return -ENOMEM;

        pcf2127->regmap = regmap;

        dev_set_drvdata(dev, pcf2127);

        pcf2127->rtc = devm_rtc_allocate_device(dev);
        if (IS_ERR(pcf2127->rtc))
                return PTR_ERR(pcf2127->rtc);

        pcf2127->rtc->ops = &pcf2127_rtc_ops;

        pcf2127->wdd.parent = dev;
        pcf2127->wdd.info = &pcf2127_wdt_info;
        pcf2127->wdd.ops = &pcf2127_watchdog_ops;
        pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
        pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
        pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
        pcf2127->wdd.min_hw_heartbeat_ms = 500;

        watchdog_set_drvdata(&pcf2127->wdd, pcf2127);

        if (has_nvmem) {
                struct nvmem_config nvmem_cfg = {
                        .priv = pcf2127,
                        .reg_read = pcf2127_nvmem_read,
                        .reg_write = pcf2127_nvmem_write,
                        .size = 512,
                };

                ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
        }

        /*
         * Watchdog timer enabled and reset pin /RST activated when timed out.
         * Select 1Hz clock source for watchdog timer.
         * Note: Countdown timer disabled and not available.
         */
        ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_WD_CTL,
                                 PCF2127_BIT_WD_CTL_CD1 |
                                 PCF2127_BIT_WD_CTL_CD0 |
                                 PCF2127_BIT_WD_CTL_TF1 |
                                 PCF2127_BIT_WD_CTL_TF0,
                                 PCF2127_BIT_WD_CTL_CD1 |
                                 PCF2127_BIT_WD_CTL_CD0 |
                                 PCF2127_BIT_WD_CTL_TF1);
        if (ret) {
                dev_err(dev, "%s: watchdog config (wd_ctl) failed\n", __func__);
                return ret;
        }

        /* Test if watchdog timer is started by bootloader */
        ret = regmap_read(pcf2127->regmap, PCF2127_REG_WD_VAL, &wdd_timeout);
        if (ret)
                return ret;

        if (wdd_timeout)
                set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);

#ifdef CONFIG_WATCHDOG
        ret = devm_watchdog_register_device(dev, &pcf2127->wdd);
        if (ret)
                return ret;
#endif /* CONFIG_WATCHDOG */

        /*
         * Disable battery low/switch-over timestamp and interrupts.
         * Clear battery interrupt flags which can block new trigger events.
         * Note: This is the default chip behaviour but added to ensure
         * correct tamper timestamp and interrupt function.
         */
        ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
                                 PCF2127_BIT_CTRL3_BTSE |
                                 PCF2127_BIT_CTRL3_BF |
                                 PCF2127_BIT_CTRL3_BIE |
                                 PCF2127_BIT_CTRL3_BLIE, 0);
        if (ret) {
                dev_err(dev, "%s: interrupt config (ctrl3) failed\n",
                        __func__);
                return ret;
        }

        /*
         * Enable timestamp function and store timestamp of first trigger
         * event until TSF1 and TFS2 interrupt flags are cleared.
         */
        ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_TS_CTRL,
                                 PCF2127_BIT_TS_CTRL_TSOFF |
                                 PCF2127_BIT_TS_CTRL_TSM,
                                 PCF2127_BIT_TS_CTRL_TSM);
        if (ret) {
                dev_err(dev, "%s: tamper detection config (ts_ctrl) failed\n",
                        __func__);
                return ret;
        }

        /*
         * Enable interrupt generation when TSF1 or TSF2 timestamp flags
         * are set. Interrupt signal is an open-drain output and can be
         * left floating if unused.
         */
        ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
                                 PCF2127_BIT_CTRL2_TSIE,
                                 PCF2127_BIT_CTRL2_TSIE);
        if (ret) {
                dev_err(dev, "%s: tamper detection config (ctrl2) failed\n",
                        __func__);
                return ret;
        }

        ret = rtc_add_group(pcf2127->rtc, &pcf2127_attr_group);
        if (ret) {
                dev_err(dev, "%s: tamper sysfs registering failed\n",
                        __func__);
                return ret;
        }

        return rtc_register_device(pcf2127->rtc);
}

#ifdef CONFIG_OF
static const struct of_device_id pcf2127_of_match[] = {
        { .compatible = "nxp,pcf2127" },
        { .compatible = "nxp,pcf2129" },
        {}
};
MODULE_DEVICE_TABLE(of, pcf2127_of_match);
#endif

#if IS_ENABLED(CONFIG_I2C)

static int pcf2127_i2c_write(void *context, const void *data, size_t count)
{
        struct device *dev = context;
        struct i2c_client *client = to_i2c_client(dev);
        int ret;

        ret = i2c_master_send(client, data, count);
        if (ret != count)
                return ret < 0 ? ret : -EIO;

        return 0;
}

static int pcf2127_i2c_gather_write(void *context,
                                const void *reg, size_t reg_size,
                                const void *val, size_t val_size)
{
        struct device *dev = context;
        struct i2c_client *client = to_i2c_client(dev);
        int ret;
        void *buf;

        if (WARN_ON(reg_size != 1))
                return -EINVAL;

        buf = kmalloc(val_size + 1, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        memcpy(buf, reg, 1);
        memcpy(buf + 1, val, val_size);

        ret = i2c_master_send(client, buf, val_size + 1);

        kfree(buf);

        if (ret != val_size + 1)
                return ret < 0 ? ret : -EIO;

        return 0;
}

static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
                                void *val, size_t val_size)
{
        struct device *dev = context;
        struct i2c_client *client = to_i2c_client(dev);
        int ret;

        if (WARN_ON(reg_size != 1))
                return -EINVAL;

        ret = i2c_master_send(client, reg, 1);
        if (ret != 1)
                return ret < 0 ? ret : -EIO;

        ret = i2c_master_recv(client, val, val_size);
        if (ret != val_size)
                return ret < 0 ? ret : -EIO;

        return 0;
}

/*
 * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 * is that the STOP condition is required between set register address and
 * read register data when reading from registers.
 */
static const struct regmap_bus pcf2127_i2c_regmap = {
        .write = pcf2127_i2c_write,
        .gather_write = pcf2127_i2c_gather_write,
        .read = pcf2127_i2c_read,
};

static struct i2c_driver pcf2127_i2c_driver;

static int pcf2127_i2c_probe(struct i2c_client *client,
                                const struct i2c_device_id *id)
{
        struct regmap *regmap;
        static const struct regmap_config config = {
                .reg_bits = 8,
                .val_bits = 8,
        };

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
                return -ENODEV;

        regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
                                        &client->dev, &config);
        if (IS_ERR(regmap)) {
                dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
                        __func__, PTR_ERR(regmap));
                return PTR_ERR(regmap);
        }

        return pcf2127_probe(&client->dev, regmap,
                             pcf2127_i2c_driver.driver.name, id->driver_data);
}

static const struct i2c_device_id pcf2127_i2c_id[] = {
        { "pcf2127", 1 },
        { "pcf2129", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);

static struct i2c_driver pcf2127_i2c_driver = {
        .driver         = {
                .name   = "rtc-pcf2127-i2c",
                .of_match_table = of_match_ptr(pcf2127_of_match),
        },
        .probe          = pcf2127_i2c_probe,
        .id_table       = pcf2127_i2c_id,
};

static int pcf2127_i2c_register_driver(void)
{
        return i2c_add_driver(&pcf2127_i2c_driver);
}

static void pcf2127_i2c_unregister_driver(void)
{
        i2c_del_driver(&pcf2127_i2c_driver);
}

#else

static int pcf2127_i2c_register_driver(void)
{
        return 0;
}

static void pcf2127_i2c_unregister_driver(void)
{
}

#endif

#if IS_ENABLED(CONFIG_SPI_MASTER)

static struct spi_driver pcf2127_spi_driver;

static int pcf2127_spi_probe(struct spi_device *spi)
{
        static const struct regmap_config config = {
                .reg_bits = 8,
                .val_bits = 8,
                .read_flag_mask = 0xa0,
                .write_flag_mask = 0x20,
        };
        struct regmap *regmap;

        regmap = devm_regmap_init_spi(spi, &config);
        if (IS_ERR(regmap)) {
                dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
                        __func__, PTR_ERR(regmap));
                return PTR_ERR(regmap);
        }

        return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
                             spi_get_device_id(spi)->driver_data);
}

static const struct spi_device_id pcf2127_spi_id[] = {
        { "pcf2127", 1 },
        { "pcf2129", 0 },
        { }
};
MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);

static struct spi_driver pcf2127_spi_driver = {
        .driver         = {
                .name   = "rtc-pcf2127-spi",
                .of_match_table = of_match_ptr(pcf2127_of_match),
        },
        .probe          = pcf2127_spi_probe,
        .id_table       = pcf2127_spi_id,
};

static int pcf2127_spi_register_driver(void)
{
        return spi_register_driver(&pcf2127_spi_driver);
}

static void pcf2127_spi_unregister_driver(void)
{
        spi_unregister_driver(&pcf2127_spi_driver);
}

#else

static int pcf2127_spi_register_driver(void)
{
        return 0;
}

static void pcf2127_spi_unregister_driver(void)
{
}

#endif

static int __init pcf2127_init(void)
{
        int ret;

        ret = pcf2127_i2c_register_driver();
        if (ret) {
                pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
                return ret;
        }

        ret = pcf2127_spi_register_driver();
        if (ret) {
                pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
                pcf2127_i2c_unregister_driver();
        }

        return ret;
}
module_init(pcf2127_init)

static void __exit pcf2127_exit(void)
{
        pcf2127_spi_unregister_driver();
        pcf2127_i2c_unregister_driver();
}
module_exit(pcf2127_exit)

MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
MODULE_LICENSE("GPL v2");