diff options
Diffstat (limited to 'drivers/rtc/rtc-m48t35.c')
| -rw-r--r-- | drivers/rtc/rtc-m48t35.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-m48t35.c b/drivers/rtc/rtc-m48t35.c new file mode 100644 index 00000000000..0b219755994 --- /dev/null +++ b/drivers/rtc/rtc-m48t35.c @@ -0,0 +1,235 @@ +/* + * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip + * + * Copyright (C) 2000 Silicon Graphics, Inc. + * Written by Ulf Carlsson (ulfc@engr.sgi.com) + * + * 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/io.h> + +#define DRV_VERSION "1.0" + +struct m48t35_rtc { + u8 pad[0x7ff8]; /* starts at 0x7ff8 */ + u8 control; + u8 sec; + u8 min; + u8 hour; + u8 day; + u8 date; + u8 month; + u8 year; +}; + +#define M48T35_RTC_SET 0x80 +#define M48T35_RTC_READ 0x40 + +struct m48t35_priv { + struct rtc_device *rtc; + struct m48t35_rtc __iomem *reg; + size_t size; + unsigned long baseaddr; + spinlock_t lock; +}; + +static int m48t35_read_time(struct device *dev, struct rtc_time *tm) +{ + struct m48t35_priv *priv = dev_get_drvdata(dev); + u8 control; + + /* + * 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_irq(&priv->lock); + control = readb(&priv->reg->control); + writeb(control | M48T35_RTC_READ, &priv->reg->control); + tm->tm_sec = readb(&priv->reg->sec); + tm->tm_min = readb(&priv->reg->min); + tm->tm_hour = readb(&priv->reg->hour); + tm->tm_mday = readb(&priv->reg->date); + tm->tm_mon = readb(&priv->reg->month); + tm->tm_year = readb(&priv->reg->year); + writeb(control, &priv->reg->control); + spin_unlock_irq(&priv->lock); + + 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; + */ + tm->tm_year += 70; + if (tm->tm_year <= 69) + tm->tm_year += 100; + + tm->tm_mon--; + return rtc_valid_tm(tm); +} + +static int m48t35_set_time(struct device *dev, struct rtc_time *tm) +{ + struct m48t35_priv *priv = dev_get_drvdata(dev); + unsigned char mon, day, hrs, min, sec; + unsigned int yrs; + u8 control; + + 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 -= 1970; + if (yrs > 255) /* They are unsigned */ + return -EINVAL; + + if (yrs > 169) + 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_irq(&priv->lock); + control = readb(&priv->reg->control); + writeb(control | M48T35_RTC_SET, &priv->reg->control); + writeb(yrs, &priv->reg->year); + writeb(mon, &priv->reg->month); + writeb(day, &priv->reg->date); + writeb(hrs, &priv->reg->hour); + writeb(min, &priv->reg->min); + writeb(sec, &priv->reg->sec); + writeb(control, &priv->reg->control); + spin_unlock_irq(&priv->lock); + return 0; +} + +static const struct rtc_class_ops m48t35_ops = { + .read_time = m48t35_read_time, + .set_time = m48t35_set_time, +}; + +static int __devinit m48t35_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + struct resource *res; + struct m48t35_priv *priv; + int ret = 0; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + priv = kzalloc(sizeof(struct m48t35_priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->size = res->end - res->start + 1; + /* + * kludge: remove the #ifndef after ioc3 resource + * conflicts are resolved + */ +#ifndef CONFIG_SGI_IP27 + if (!request_mem_region(res->start, priv->size, pdev->name)) { + ret = -EBUSY; + goto out; + } +#endif + priv->baseaddr = res->start; + priv->reg = ioremap(priv->baseaddr, priv->size); + if (!priv->reg) { + ret = -ENOMEM; + goto out; + } + spin_lock_init(&priv->lock); + rtc = rtc_device_register("m48t35", &pdev->dev, + &m48t35_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->reg) + iounmap(priv->reg); + if (priv->baseaddr) + release_mem_region(priv->baseaddr, priv->size); + kfree(priv); + return ret; +} + +static int __devexit m48t35_remove(struct platform_device *pdev) +{ + struct m48t35_priv *priv = platform_get_drvdata(pdev); + + rtc_device_unregister(priv->rtc); + iounmap(priv->reg); +#ifndef CONFIG_SGI_IP27 + release_mem_region(priv->baseaddr, priv->size); +#endif + kfree(priv); + return 0; +} + +static struct platform_driver m48t35_platform_driver = { + .driver = { + .name = "rtc-m48t35", + .owner = THIS_MODULE, + }, + .probe = m48t35_probe, + .remove = __devexit_p(m48t35_remove), +}; + +static int __init m48t35_init(void) +{ + return platform_driver_register(&m48t35_platform_driver); +} + +static void __exit m48t35_exit(void) +{ + platform_driver_unregister(&m48t35_platform_driver); +} + +MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); +MODULE_DESCRIPTION("M48T35 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); +MODULE_ALIAS("platform:rtc-m48t35"); + +module_init(m48t35_init); +module_exit(m48t35_exit); |