Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / rtc / rtc-rs5c372.c
diff --git a/kernel/drivers/rtc/rtc-rs5c372.c b/kernel/drivers/rtc/rtc-rs5c372.c
new file mode 100644 (file)
index 0000000..28871cd
--- /dev/null
@@ -0,0 +1,699 @@
+/*
+ * An I2C driver for Ricoh RS5C372, R2025S/D and RV5C38[67] RTCs
+ *
+ * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
+ * Copyright (C) 2006 Tower Technologies
+ * Copyright (C) 2008 Paul Mundt
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#define DRV_VERSION "0.6"
+
+
+/*
+ * Ricoh has a family of I2C based RTCs, which differ only slightly from
+ * each other.  Differences center on pinout (e.g. how many interrupts,
+ * output clock, etc) and how the control registers are used.  The '372
+ * is significant only because that's the one this driver first supported.
+ */
+#define RS5C372_REG_SECS       0
+#define RS5C372_REG_MINS       1
+#define RS5C372_REG_HOURS      2
+#define RS5C372_REG_WDAY       3
+#define RS5C372_REG_DAY                4
+#define RS5C372_REG_MONTH      5
+#define RS5C372_REG_YEAR       6
+#define RS5C372_REG_TRIM       7
+#      define RS5C372_TRIM_XSL         0x80
+#      define RS5C372_TRIM_MASK        0x7F
+
+#define RS5C_REG_ALARM_A_MIN   8                       /* or ALARM_W */
+#define RS5C_REG_ALARM_A_HOURS 9
+#define RS5C_REG_ALARM_A_WDAY  10
+
+#define RS5C_REG_ALARM_B_MIN   11                      /* or ALARM_D */
+#define RS5C_REG_ALARM_B_HOURS 12
+#define RS5C_REG_ALARM_B_WDAY  13                      /* (ALARM_B only) */
+
+#define RS5C_REG_CTRL1         14
+#      define RS5C_CTRL1_AALE          (1 << 7)        /* or WALE */
+#      define RS5C_CTRL1_BALE          (1 << 6)        /* or DALE */
+#      define RV5C387_CTRL1_24         (1 << 5)
+#      define RS5C372A_CTRL1_SL1       (1 << 5)
+#      define RS5C_CTRL1_CT_MASK       (7 << 0)
+#      define RS5C_CTRL1_CT0           (0 << 0)        /* no periodic irq */
+#      define RS5C_CTRL1_CT4           (4 << 0)        /* 1 Hz level irq */
+#define RS5C_REG_CTRL2         15
+#      define RS5C372_CTRL2_24         (1 << 5)
+#      define R2025_CTRL2_XST          (1 << 5)
+#      define RS5C_CTRL2_XSTP          (1 << 4)        /* only if !R2025S/D */
+#      define RS5C_CTRL2_CTFG          (1 << 2)
+#      define RS5C_CTRL2_AAFG          (1 << 1)        /* or WAFG */
+#      define RS5C_CTRL2_BAFG          (1 << 0)        /* or DAFG */
+
+
+/* to read (style 1) or write registers starting at R */
+#define RS5C_ADDR(R)           (((R) << 4) | 0)
+
+
+enum rtc_type {
+       rtc_undef = 0,
+       rtc_r2025sd,
+       rtc_r2221tl,
+       rtc_rs5c372a,
+       rtc_rs5c372b,
+       rtc_rv5c386,
+       rtc_rv5c387a,
+};
+
+static const struct i2c_device_id rs5c372_id[] = {
+       { "r2025sd", rtc_r2025sd },
+       { "r2221tl", rtc_r2221tl },
+       { "rs5c372a", rtc_rs5c372a },
+       { "rs5c372b", rtc_rs5c372b },
+       { "rv5c386", rtc_rv5c386 },
+       { "rv5c387a", rtc_rv5c387a },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, rs5c372_id);
+
+/* REVISIT:  this assumes that:
+ *  - we're in the 21st century, so it's safe to ignore the century
+ *    bit for rv5c38[67] (REG_MONTH bit 7);
+ *  - we should use ALARM_A not ALARM_B (may be wrong on some boards)
+ */
+struct rs5c372 {
+       struct i2c_client       *client;
+       struct rtc_device       *rtc;
+       enum rtc_type           type;
+       unsigned                time24:1;
+       unsigned                has_irq:1;
+       unsigned                smbus:1;
+       char                    buf[17];
+       char                    *regs;
+};
+
+static int rs5c_get_regs(struct rs5c372 *rs5c)
+{
+       struct i2c_client       *client = rs5c->client;
+       struct i2c_msg          msgs[] = {
+               {
+                       .addr = client->addr,
+                       .flags = I2C_M_RD,
+                       .len = sizeof(rs5c->buf),
+                       .buf = rs5c->buf
+               },
+       };
+
+       /* This implements the third reading method from the datasheet, using
+        * an internal address that's reset after each transaction (by STOP)
+        * to 0x0f ... so we read extra registers, and skip the first one.
+        *
+        * The first method doesn't work with the iop3xx adapter driver, on at
+        * least 80219 chips; this works around that bug.
+        *
+        * The third method on the other hand doesn't work for the SMBus-only
+        * configurations, so we use the the first method there, stripping off
+        * the extra register in the process.
+        */
+       if (rs5c->smbus) {
+               int addr = RS5C_ADDR(RS5C372_REG_SECS);
+               int size = sizeof(rs5c->buf) - 1;
+
+               if (i2c_smbus_read_i2c_block_data(client, addr, size,
+                                                 rs5c->buf + 1) != size) {
+                       dev_warn(&client->dev, "can't read registers\n");
+                       return -EIO;
+               }
+       } else {
+               if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
+                       dev_warn(&client->dev, "can't read registers\n");
+                       return -EIO;
+               }
+       }
+
+       dev_dbg(&client->dev,
+               "%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
+               rs5c->regs + 0, rs5c->regs[3],
+               rs5c->regs + 4, rs5c->regs[7],
+               rs5c->regs + 8, rs5c->regs + 11,
+               rs5c->regs[14], rs5c->regs[15]);
+
+       return 0;
+}
+
+static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
+{
+       unsigned        hour;
+
+       if (rs5c->time24)
+               return bcd2bin(reg & 0x3f);
+
+       hour = bcd2bin(reg & 0x1f);
+       if (hour == 12)
+               hour = 0;
+       if (reg & 0x20)
+               hour += 12;
+       return hour;
+}
+
+static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
+{
+       if (rs5c->time24)
+               return bin2bcd(hour);
+
+       if (hour > 12)
+               return 0x20 | bin2bcd(hour - 12);
+       if (hour == 12)
+               return 0x20 | bin2bcd(12);
+       if (hour == 0)
+               return bin2bcd(12);
+       return bin2bcd(hour);
+}
+
+static int rs5c372_get_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+       struct rs5c372  *rs5c = i2c_get_clientdata(client);
+       int             status = rs5c_get_regs(rs5c);
+
+       if (status < 0)
+               return status;
+
+       tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
+       tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
+       tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
+
+       tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
+       tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
+
+       /* tm->tm_mon is zero-based */
+       tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
+
+       /* year is 1900 + tm->tm_year */
+       tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
+
+       dev_dbg(&client->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);
+
+       /* rtc might need initialization */
+       return rtc_valid_tm(tm);
+}
+
+static int rs5c372_set_datetime(struct i2c_client *client, struct rtc_time *tm)
+{
+       struct rs5c372  *rs5c = i2c_get_clientdata(client);
+       unsigned char   buf[7];
+       int             addr;
+
+       dev_dbg(&client->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);
+
+       addr   = RS5C_ADDR(RS5C372_REG_SECS);
+       buf[0] = bin2bcd(tm->tm_sec);
+       buf[1] = bin2bcd(tm->tm_min);
+       buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
+       buf[3] = bin2bcd(tm->tm_wday);
+       buf[4] = bin2bcd(tm->tm_mday);
+       buf[5] = bin2bcd(tm->tm_mon + 1);
+       buf[6] = bin2bcd(tm->tm_year - 100);
+
+       if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
+               dev_err(&client->dev, "%s: write error\n", __func__);
+               return -EIO;
+       }
+
+       return 0;
+}
+
+#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
+#define        NEED_TRIM
+#endif
+
+#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
+#define        NEED_TRIM
+#endif
+
+#ifdef NEED_TRIM
+static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
+{
+       struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
+       u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
+
+       if (osc)
+               *osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
+
+       if (trim) {
+               dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
+               tmp &= RS5C372_TRIM_MASK;
+               if (tmp & 0x3e) {
+                       int t = tmp & 0x3f;
+
+                       if (tmp & 0x40)
+                               t = (~t | (s8)0xc0) + 1;
+                       else
+                               t = t - 1;
+
+                       tmp = t * 2;
+               } else
+                       tmp = 0;
+               *trim = tmp;
+       }
+
+       return 0;
+}
+#endif
+
+static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+       return rs5c372_get_datetime(to_i2c_client(dev), tm);
+}
+
+static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+       return rs5c372_set_datetime(to_i2c_client(dev), tm);
+}
+
+
+static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+       struct i2c_client       *client = to_i2c_client(dev);
+       struct rs5c372          *rs5c = i2c_get_clientdata(client);
+       unsigned char           buf;
+       int                     status, addr;
+
+       buf = rs5c->regs[RS5C_REG_CTRL1];
+
+       if (!rs5c->has_irq)
+               return -EINVAL;
+
+       status = rs5c_get_regs(rs5c);
+       if (status < 0)
+               return status;
+
+       addr = RS5C_ADDR(RS5C_REG_CTRL1);
+       if (enabled)
+               buf |= RS5C_CTRL1_AALE;
+       else
+               buf &= ~RS5C_CTRL1_AALE;
+
+       if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
+               dev_warn(dev, "can't update alarm\n");
+               status = -EIO;
+       } else
+               rs5c->regs[RS5C_REG_CTRL1] = buf;
+
+       return status;
+}
+
+
+/* NOTE:  Since RTC_WKALM_{RD,SET} were originally defined for EFI,
+ * which only exposes a polled programming interface; and since
+ * these calls map directly to those EFI requests; we don't demand
+ * we have an IRQ for this chip when we go through this API.
+ *
+ * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
+ * though, managed through RTC_AIE_{ON,OFF} requests.
+ */
+
+static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+       struct i2c_client       *client = to_i2c_client(dev);
+       struct rs5c372          *rs5c = i2c_get_clientdata(client);
+       int                     status;
+
+       status = rs5c_get_regs(rs5c);
+       if (status < 0)
+               return status;
+
+       /* report alarm time */
+       t->time.tm_sec = 0;
+       t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
+       t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
+       t->time.tm_mday = -1;
+       t->time.tm_mon = -1;
+       t->time.tm_year = -1;
+       t->time.tm_wday = -1;
+       t->time.tm_yday = -1;
+       t->time.tm_isdst = -1;
+
+       /* ... and status */
+       t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
+       t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
+
+       return 0;
+}
+
+static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+       struct i2c_client       *client = to_i2c_client(dev);
+       struct rs5c372          *rs5c = i2c_get_clientdata(client);
+       int                     status, addr, i;
+       unsigned char           buf[3];
+
+       /* only handle up to 24 hours in the future, like RTC_ALM_SET */
+       if (t->time.tm_mday != -1
+                       || t->time.tm_mon != -1
+                       || t->time.tm_year != -1)
+               return -EINVAL;
+
+       /* REVISIT: round up tm_sec */
+
+       /* if needed, disable irq (clears pending status) */
+       status = rs5c_get_regs(rs5c);
+       if (status < 0)
+               return status;
+       if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
+               addr = RS5C_ADDR(RS5C_REG_CTRL1);
+               buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
+               if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
+                       dev_dbg(dev, "can't disable alarm\n");
+                       return -EIO;
+               }
+               rs5c->regs[RS5C_REG_CTRL1] = buf[0];
+       }
+
+       /* set alarm */
+       buf[0] = bin2bcd(t->time.tm_min);
+       buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
+       buf[2] = 0x7f;  /* any/all days */
+
+       for (i = 0; i < sizeof(buf); i++) {
+               addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
+               if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
+                       dev_dbg(dev, "can't set alarm time\n");
+                       return -EIO;
+               }
+       }
+
+       /* ... and maybe enable its irq */
+       if (t->enabled) {
+               addr = RS5C_ADDR(RS5C_REG_CTRL1);
+               buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
+               if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
+                       dev_warn(dev, "can't enable alarm\n");
+               rs5c->regs[RS5C_REG_CTRL1] = buf[0];
+       }
+
+       return 0;
+}
+
+#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
+
+static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+       int err, osc, trim;
+
+       err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
+       if (err == 0) {
+               seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
+                               osc / 1000, osc % 1000);
+               seq_printf(seq, "trim\t\t: %d\n", trim);
+       }
+
+       return 0;
+}
+
+#else
+#define        rs5c372_rtc_proc        NULL
+#endif
+
+static const struct rtc_class_ops rs5c372_rtc_ops = {
+       .proc           = rs5c372_rtc_proc,
+       .read_time      = rs5c372_rtc_read_time,
+       .set_time       = rs5c372_rtc_set_time,
+       .read_alarm     = rs5c_read_alarm,
+       .set_alarm      = rs5c_set_alarm,
+       .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
+};
+
+#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
+
+static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       int err, trim;
+
+       err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
+       if (err)
+               return err;
+
+       return sprintf(buf, "%d\n", trim);
+}
+static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
+
+static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       int err, osc;
+
+       err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
+       if (err)
+               return err;
+
+       return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
+}
+static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
+
+static int rs5c_sysfs_register(struct device *dev)
+{
+       int err;
+
+       err = device_create_file(dev, &dev_attr_trim);
+       if (err)
+               return err;
+       err = device_create_file(dev, &dev_attr_osc);
+       if (err)
+               device_remove_file(dev, &dev_attr_trim);
+
+       return err;
+}
+
+static void rs5c_sysfs_unregister(struct device *dev)
+{
+       device_remove_file(dev, &dev_attr_trim);
+       device_remove_file(dev, &dev_attr_osc);
+}
+
+#else
+static int rs5c_sysfs_register(struct device *dev)
+{
+       return 0;
+}
+
+static void rs5c_sysfs_unregister(struct device *dev)
+{
+       /* nothing */
+}
+#endif /* SYSFS */
+
+static struct i2c_driver rs5c372_driver;
+
+static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
+{
+       unsigned char buf[2];
+       int addr, i, ret = 0;
+
+       if (rs5c372->type == rtc_r2025sd) {
+               if (!(rs5c372->regs[RS5C_REG_CTRL2] & R2025_CTRL2_XST))
+                       return ret;
+               rs5c372->regs[RS5C_REG_CTRL2] &= ~R2025_CTRL2_XST;
+       } else {
+               if (!(rs5c372->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_XSTP))
+                       return ret;
+               rs5c372->regs[RS5C_REG_CTRL2] &= ~RS5C_CTRL2_XSTP;
+       }
+
+       addr   = RS5C_ADDR(RS5C_REG_CTRL1);
+       buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
+       buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
+
+       /* use 24hr mode */
+       switch (rs5c372->type) {
+       case rtc_rs5c372a:
+       case rtc_rs5c372b:
+               buf[1] |= RS5C372_CTRL2_24;
+               rs5c372->time24 = 1;
+               break;
+       case rtc_r2025sd:
+       case rtc_r2221tl:
+       case rtc_rv5c386:
+       case rtc_rv5c387a:
+               buf[0] |= RV5C387_CTRL1_24;
+               rs5c372->time24 = 1;
+               break;
+       default:
+               /* impossible */
+               break;
+       }
+
+       for (i = 0; i < sizeof(buf); i++) {
+               addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
+               ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
+               if (unlikely(ret < 0))
+                       return ret;
+       }
+
+       rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
+       rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
+
+       return 0;
+}
+
+static int rs5c372_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+       int err = 0;
+       int smbus_mode = 0;
+       struct rs5c372 *rs5c372;
+       struct rtc_time tm;
+
+       dev_dbg(&client->dev, "%s\n", __func__);
+
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
+                       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
+               /*
+                * If we don't have any master mode adapter, try breaking
+                * it down in to the barest of capabilities.
+                */
+               if (i2c_check_functionality(client->adapter,
+                               I2C_FUNC_SMBUS_BYTE_DATA |
+                               I2C_FUNC_SMBUS_I2C_BLOCK))
+                       smbus_mode = 1;
+               else {
+                       /* Still no good, give up */
+                       err = -ENODEV;
+                       goto exit;
+               }
+       }
+
+       rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
+                               GFP_KERNEL);
+       if (!rs5c372) {
+               err = -ENOMEM;
+               goto exit;
+       }
+
+       rs5c372->client = client;
+       i2c_set_clientdata(client, rs5c372);
+       rs5c372->type = id->driver_data;
+
+       /* we read registers 0x0f then 0x00-0x0f; skip the first one */
+       rs5c372->regs = &rs5c372->buf[1];
+       rs5c372->smbus = smbus_mode;
+
+       err = rs5c_get_regs(rs5c372);
+       if (err < 0)
+               goto exit;
+
+       /* clock may be set for am/pm or 24 hr time */
+       switch (rs5c372->type) {
+       case rtc_rs5c372a:
+       case rtc_rs5c372b:
+               /* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
+                * so does periodic irq, except some 327a modes.
+                */
+               if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
+                       rs5c372->time24 = 1;
+               break;
+       case rtc_r2025sd:
+       case rtc_r2221tl:
+       case rtc_rv5c386:
+       case rtc_rv5c387a:
+               if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
+                       rs5c372->time24 = 1;
+               /* alarm uses ALARM_W; and nINTRB for alarm and periodic
+                * irq, on both 386 and 387
+                */
+               break;
+       default:
+               dev_err(&client->dev, "unknown RTC type\n");
+               goto exit;
+       }
+
+       /* if the oscillator lost power and no other software (like
+        * the bootloader) set it up, do it here.
+        *
+        * The R2025S/D does this a little differently than the other
+        * parts, so we special case that..
+        */
+       err = rs5c_oscillator_setup(rs5c372);
+       if (unlikely(err < 0)) {
+               dev_err(&client->dev, "setup error\n");
+               goto exit;
+       }
+
+       if (rs5c372_get_datetime(client, &tm) < 0)
+               dev_warn(&client->dev, "clock needs to be set\n");
+
+       dev_info(&client->dev, "%s found, %s, driver version " DRV_VERSION "\n",
+                       ({ char *s; switch (rs5c372->type) {
+                       case rtc_r2025sd:       s = "r2025sd"; break;
+                       case rtc_r2221tl:       s = "r2221tl"; break;
+                       case rtc_rs5c372a:      s = "rs5c372a"; break;
+                       case rtc_rs5c372b:      s = "rs5c372b"; break;
+                       case rtc_rv5c386:       s = "rv5c386"; break;
+                       case rtc_rv5c387a:      s = "rv5c387a"; break;
+                       default:                s = "chip"; break;
+                       }; s;}),
+                       rs5c372->time24 ? "24hr" : "am/pm"
+                       );
+
+       /* REVISIT use client->irq to register alarm irq ... */
+       rs5c372->rtc = devm_rtc_device_register(&client->dev,
+                                       rs5c372_driver.driver.name,
+                                       &rs5c372_rtc_ops, THIS_MODULE);
+
+       if (IS_ERR(rs5c372->rtc)) {
+               err = PTR_ERR(rs5c372->rtc);
+               goto exit;
+       }
+
+       err = rs5c_sysfs_register(&client->dev);
+       if (err)
+               goto exit;
+
+       return 0;
+
+exit:
+       return err;
+}
+
+static int rs5c372_remove(struct i2c_client *client)
+{
+       rs5c_sysfs_unregister(&client->dev);
+       return 0;
+}
+
+static struct i2c_driver rs5c372_driver = {
+       .driver         = {
+               .name   = "rtc-rs5c372",
+       },
+       .probe          = rs5c372_probe,
+       .remove         = rs5c372_remove,
+       .id_table       = rs5c372_id,
+};
+
+module_i2c_driver(rs5c372_driver);
+
+MODULE_AUTHOR(
+               "Pavel Mironchik <pmironchik@optifacio.net>, "
+               "Alessandro Zummo <a.zummo@towertech.it>, "
+               "Paul Mundt <lethal@linux-sh.org>");
+MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);