/* * 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 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); platform_set_drvdata(pdev, priv); priv->rtc = rtc_device_register("m48t35", &pdev->dev, &m48t35_ops, THIS_MODULE); if (IS_ERR(priv->rtc)) { ret = PTR_ERR(priv->rtc); goto out; } return 0; out: 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);