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[PATCH v2] DS1286: new RTC driver

To: rtc-linux@googlegroups.com, linux-mips@linux-mips.org
Subject: [PATCH v2] DS1286: new RTC driver
From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Date: Sat, 9 Aug 2008 12:25:28 +0200 (CEST)
Cc: a.zummo@towertech.it, ralf@linux-mips.org
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
This driver replaces the broken DS1286 driver in drivers/char and
gives back RTC support for SGI IP22 and IP28 machines.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
---

Changes in v2:

- switch to bcd2bin/bin2bcd
- do kzalloc with sizeof(struct ds1286_priv)
- don't depend on SGI_HAS_DS1286
- use rtc_valid_tm() for tm validation


 drivers/rtc/Kconfig      |    5 +
 drivers/rtc/Makefile     |    1 +
 drivers/rtc/rtc-ds1286.c |  413 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 419 insertions(+), 0 deletions(-)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 90ab738..ad4539a 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -352,6 +352,11 @@ config RTC_DRV_DS1216
        help
          If you say yes here you get support for the Dallas DS1216 RTC chips.
 
+config RTC_DRV_DS1286
+       tristate "Dallas DS1286"
+       help
+         If you say yes here you get support for the Dallas DS1286 RTC chips.
+
 config RTC_DRV_DS1302
        tristate "Dallas DS1302"
        depends on SH_SECUREEDGE5410
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 18622ef..e060802 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_RTC_DRV_AT91SAM9)        += rtc-at91sam9.o
 obj-$(CONFIG_RTC_DRV_BFIN)     += rtc-bfin.o
 obj-$(CONFIG_RTC_DRV_CMOS)     += rtc-cmos.o
 obj-$(CONFIG_RTC_DRV_DS1216)   += rtc-ds1216.o
+obj-$(CONFIG_RTC_DRV_DS1286)   += rtc-ds1286.o
 obj-$(CONFIG_RTC_DRV_DS1302)   += rtc-ds1302.o
 obj-$(CONFIG_RTC_DRV_DS1305)   += rtc-ds1305.o
 obj-$(CONFIG_RTC_DRV_DS1307)   += rtc-ds1307.o
diff --git a/drivers/rtc/rtc-ds1286.c b/drivers/rtc/rtc-ds1286.c
new file mode 100644
index 0000000..8a47855
--- /dev/null
+++ b/drivers/rtc/rtc-ds1286.c
@@ -0,0 +1,413 @@
+/*
+ * DS1286 Real Time Clock interface for Linux
+ *
+ * Copyright (C) 1998, 1999, 2000 Ralf Baechle
+ * Copyright (C) 2008 Thomas Bogendoerfer
+ *
+ * Based on code written by Paul Gortmaker.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/bcd.h>
+#include <linux/ds1286.h>
+
+#define DRV_VERSION            "1.0"
+
+struct ds1286_priv {
+       struct rtc_device *rtc;
+       u32 __iomem *rtcregs;
+       size_t size;
+       unsigned long baseaddr;
+       spinlock_t lock;
+};
+
+static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
+{
+       return __raw_readl(&priv->rtcregs[reg]) & 0xff;
+}
+
+static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
+{
+       __raw_writel(data, &priv->rtcregs[reg]);
+}
+
+#ifdef CONFIG_RTC_INTF_DEV
+
+static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long 
arg)
+{
+       struct ds1286_priv *priv = dev_get_drvdata(dev);
+       unsigned long flags;
+       unsigned char val;
+
+       switch (cmd) {
+       case RTC_AIE_OFF:
+               /* Mask alarm int. enab. bit    */
+               spin_lock_irqsave(&priv->lock, flags);
+               val = ds1286_rtc_read(priv, RTC_CMD);
+               val |=  RTC_TDM;
+               ds1286_rtc_write(priv, val, RTC_CMD);
+               spin_unlock_irqrestore(&priv->lock, flags);
+               break;
+       case RTC_AIE_ON:
+               /* Allow alarm interrupts.      */
+               spin_lock_irqsave(&priv->lock, flags);
+               val = ds1286_rtc_read(priv, RTC_CMD);
+               val &=  ~RTC_TDM;
+               ds1286_rtc_write(priv, val, RTC_CMD);
+               spin_unlock_irqrestore(&priv->lock, flags);
+               break;
+       case RTC_WIE_OFF:
+               /* Mask watchdog int. enab. bit */
+               spin_lock_irqsave(&priv->lock, flags);
+               val = ds1286_rtc_read(priv, RTC_CMD);
+               val |= RTC_WAM;
+               ds1286_rtc_write(priv, val, RTC_CMD);
+               spin_unlock_irqrestore(&priv->lock, flags);
+               break;
+       case RTC_WIE_ON:
+               /* Allow watchdog interrupts.   */
+               spin_lock_irqsave(&priv->lock, flags);
+               val = ds1286_rtc_read(priv, RTC_CMD);
+               val &= ~RTC_WAM;
+               ds1286_rtc_write(priv, val, RTC_CMD);
+               spin_unlock_irqrestore(&priv->lock, flags);
+               break;
+       default:
+               return -ENOIOCTLCMD;
+       }
+       return 0;
+}
+
+#else
+#define ds1286_ioctl    NULL
+#endif
+
+#ifdef CONFIG_PROC_FS
+
+static int ds1286_proc(struct device *dev, struct seq_file *seq)
+{
+       struct ds1286_priv *priv = dev_get_drvdata(dev);
+       unsigned char month, cmd, amode;
+       const char *s;
+
+       month = ds1286_rtc_read(priv, RTC_MONTH);
+       seq_printf(seq,
+                  "oscillator\t: %s\n"
+                  "square_wave\t: %s\n",
+                  (month & RTC_EOSC) ? "disabled" : "enabled",
+                  (month & RTC_ESQW) ? "disabled" : "enabled");
+
+       amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
+               ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
+               ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
+       switch (amode) {
+       case 7:
+               s = "each minute";
+               break;
+       case 3:
+               s = "minutes match";
+               break;
+       case 1:
+               s = "hours and minutes match";
+               break;
+       case 0:
+               s = "days, hours and minutes match";
+               break;
+       default:
+               s = "invalid";
+               break;
+       }
+       seq_printf(seq, "alarm_mode\t: %s\n", s);
+
+       cmd = ds1286_rtc_read(priv, RTC_CMD);
+       seq_printf(seq,
+                  "alarm_enable\t: %s\n"
+                  "wdog_alarm\t: %s\n"
+                  "alarm_mask\t: %s\n"
+                  "wdog_alarm_mask\t: %s\n"
+                  "interrupt_mode\t: %s\n"
+                  "INTB_mode\t: %s_active\n"
+                  "interrupt_pins\t: %s\n",
+                  (cmd & RTC_TDF) ? "yes" : "no",
+                  (cmd & RTC_WAF) ? "yes" : "no",
+                  (cmd & RTC_TDM) ? "disabled" : "enabled",
+                  (cmd & RTC_WAM) ? "disabled" : "enabled",
+                  (cmd & RTC_PU_LVL) ? "pulse" : "level",
+                  (cmd & RTC_IBH_LO) ? "low" : "high",
+                  (cmd & RTC_IPSW) ? "unswapped" : "swapped");
+       return 0;
+}
+
+#else
+#define ds1286_proc     NULL
+#endif
+
+static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
+{
+       struct ds1286_priv *priv = dev_get_drvdata(dev);
+       unsigned char save_control;
+       unsigned long flags;
+       unsigned long uip_watchdog = jiffies;
+
+       /*
+        * read RTC once any update in progress is done. The update
+        * can take just over 2ms. We wait 10 to 20ms. There is no need to
+        * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
+        * If you need to know *exactly* when a second has started, enable
+        * periodic update complete interrupts, (via ioctl) and then
+        * immediately read /dev/rtc which will block until you get the IRQ.
+        * Once the read clears, read the RTC time (again via ioctl). Easy.
+        */
+
+       if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
+               while (time_before(jiffies, uip_watchdog + 2*HZ/100))
+                       barrier();
+
+       /*
+        * Only the values that we read from the RTC are set. We leave
+        * tm_wday, tm_yday and tm_isdst untouched. Even though the
+        * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
+        * by the RTC when initially set to a non-zero value.
+        */
+       spin_lock_irqsave(&priv->lock, flags);
+       save_control = ds1286_rtc_read(priv, RTC_CMD);
+       ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
+
+       tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
+       tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
+       tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
+       tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
+       tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
+       tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
+
+       ds1286_rtc_write(priv, save_control, RTC_CMD);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       tm->tm_sec = bcd2bin(tm->tm_sec);
+       tm->tm_min = bcd2bin(tm->tm_min);
+       tm->tm_hour = bcd2bin(tm->tm_hour);
+       tm->tm_mday = bcd2bin(tm->tm_mday);
+       tm->tm_mon = bcd2bin(tm->tm_mon);
+       tm->tm_year = bcd2bin(tm->tm_year);
+
+       /*
+        * Account for differences between how the RTC uses the values
+        * and how they are defined in a struct rtc_time;
+        */
+       if (tm->tm_year < 45)
+               tm->tm_year += 30;
+       tm->tm_year += 40;
+       if (tm->tm_year < 70)
+               tm->tm_year += 100;
+
+       tm->tm_mon--;
+
+       return rtc_valid_tm(tm);
+}
+
+static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
+{
+       struct ds1286_priv *priv = dev_get_drvdata(dev);
+       unsigned char mon, day, hrs, min, sec;
+       unsigned char save_control;
+       unsigned int yrs;
+       unsigned long flags;
+
+
+       if (!rtc_valid_tm(tm))
+               return -EINVAL;
+
+       yrs = tm->tm_year + 1900;
+       mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
+       day = tm->tm_mday;
+       hrs = tm->tm_hour;
+       min = tm->tm_min;
+       sec = tm->tm_sec;
+
+       if (yrs < 1970)
+               return -EINVAL;
+
+       yrs -= 1940;
+       if (yrs > 255)    /* They are unsigned */
+               return -EINVAL;
+
+       if (yrs >= 100)
+               yrs -= 100;
+
+       sec = bin2bcd(sec);
+       min = bin2bcd(min);
+       hrs = bin2bcd(hrs);
+       day = bin2bcd(day);
+       mon = bin2bcd(mon);
+       yrs = bin2bcd(yrs);
+
+       spin_lock_irqsave(&priv->lock, flags);
+       save_control = ds1286_rtc_read(priv, RTC_CMD);
+       ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
+
+       ds1286_rtc_write(priv, yrs, RTC_YEAR);
+       ds1286_rtc_write(priv, mon, RTC_MONTH);
+       ds1286_rtc_write(priv, day, RTC_DATE);
+       ds1286_rtc_write(priv, hrs, RTC_HOURS);
+       ds1286_rtc_write(priv, min, RTC_MINUTES);
+       ds1286_rtc_write(priv, sec, RTC_SECONDS);
+       ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
+
+       ds1286_rtc_write(priv, save_control, RTC_CMD);
+       spin_unlock_irqrestore(&priv->lock, flags);
+       return 0;
+}
+
+static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+       struct ds1286_priv *priv = dev_get_drvdata(dev);
+       unsigned char cmd;
+       unsigned long flags;
+
+       /*
+        * Only the values that we read from the RTC are set. That
+        * means only tm_wday, tm_hour, tm_min.
+        */
+       spin_lock_irqsave(&priv->lock, flags);
+       alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
+       alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
+       alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
+       cmd = ds1286_rtc_read(priv, RTC_CMD);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       alm->time.tm_min = bcd2bin(alm->time.tm_min);
+       alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
+       alm->time.tm_sec = 0;
+       return 0;
+}
+
+static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+       struct ds1286_priv *priv = dev_get_drvdata(dev);
+       unsigned char hrs, min, sec;
+
+       hrs = alm->time.tm_hour;
+       min = alm->time.tm_min;
+       sec = alm->time.tm_sec;
+
+       if (hrs >= 24)
+               hrs = 0xff;
+
+       if (min >= 60)
+               min = 0xff;
+
+       if (sec != 0)
+               return -EINVAL;
+
+       min = bin2bcd(min);
+       hrs = bin2bcd(hrs);
+
+       spin_lock(&priv->lock);
+       ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
+       ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
+       spin_unlock(&priv->lock);
+
+       return 0;
+}
+
+static const struct rtc_class_ops ds1286_ops = {
+       .ioctl          = ds1286_ioctl,
+       .proc           = ds1286_proc,
+       .read_time      = ds1286_read_time,
+       .set_time       = ds1286_set_time,
+       .read_alarm     = ds1286_read_alarm,
+       .set_alarm      = ds1286_set_alarm,
+};
+
+static int __devinit ds1286_probe(struct platform_device *pdev)
+{
+       struct rtc_device *rtc;
+       struct resource *res;
+       struct ds1286_priv *priv;
+       int ret = 0;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -ENODEV;
+       priv = kzalloc(sizeof(struct ds1286_priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       priv->size = res->end - res->start + 1;
+       if (!request_mem_region(res->start, priv->size, pdev->name)) {
+               ret = -EBUSY;
+               goto out;
+       }
+       priv->baseaddr = res->start;
+       priv->rtcregs = ioremap(priv->baseaddr, priv->size);
+       if (!priv->rtcregs) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       spin_lock_init(&priv->lock);
+       rtc = rtc_device_register("ds1286", &pdev->dev,
+                                 &ds1286_ops, THIS_MODULE);
+       if (IS_ERR(rtc)) {
+               ret = PTR_ERR(rtc);
+               goto out;
+       }
+       priv->rtc = rtc;
+       platform_set_drvdata(pdev, priv);
+       return 0;
+
+out:
+       if (priv->rtc)
+               rtc_device_unregister(priv->rtc);
+       if (priv->rtcregs)
+               iounmap(priv->rtcregs);
+       if (priv->baseaddr)
+               release_mem_region(priv->baseaddr, priv->size);
+       kfree(priv);
+       return ret;
+}
+
+static int __devexit ds1286_remove(struct platform_device *pdev)
+{
+       struct ds1286_priv *priv = platform_get_drvdata(pdev);
+
+       rtc_device_unregister(priv->rtc);
+       iounmap(priv->rtcregs);
+       release_mem_region(priv->baseaddr, priv->size);
+       kfree(priv);
+       return 0;
+}
+
+static struct platform_driver ds1286_platform_driver = {
+       .driver         = {
+               .name   = "rtc-ds1286",
+               .owner  = THIS_MODULE,
+       },
+       .probe          = ds1286_probe,
+       .remove         = __devexit_p(ds1286_remove),
+};
+
+static int __init ds1286_init(void)
+{
+       return platform_driver_register(&ds1286_platform_driver);
+}
+
+static void __exit ds1286_exit(void)
+{
+       platform_driver_unregister(&ds1286_platform_driver);
+}
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
+MODULE_DESCRIPTION("DS1286 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("platform:rtc-ds1286");
+
+module_init(ds1286_init);
+module_exit(ds1286_exit);

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