/* * Dallas DS1216 RTC driver * * Copyright (c) 2007 Thomas Bogendoerfer * */ #include <linux/module.h> #include <linux/rtc.h> #include <linux/platform_device.h> #include <linux/bcd.h> #include <linux/slab.h> struct ds1216_regs { u8 tsec; u8 sec; u8 min; u8 hour; u8 wday; u8 mday; u8 month; u8 year; }; #define DS1216_HOUR_1224 (1 << 7) #define DS1216_HOUR_AMPM (1 << 5) struct ds1216_priv { struct rtc_device *rtc; void __iomem *ioaddr; }; static const u8 magic[] = { 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c }; /* * Read the 64 bit we'd like to have - It a series * of 64 bits showing up in the LSB of the base register. * */ static void ds1216_read(u8 __iomem *ioaddr, u8 *buf) { unsigned char c; int i, j; for (i = 0; i < 8; i++) { c = 0; for (j = 0; j < 8; j++) c |= (readb(ioaddr) & 0x1) << j; buf[i] = c; } } static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf) { unsigned char c; int i, j; for (i = 0; i < 8; i++) { c = buf[i]; for (j = 0; j < 8; j++) { writeb(c, ioaddr); c = c >> 1; } } } static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr) { /* Reset magic pointer */ readb(ioaddr); /* Write 64 bit magic to DS1216 */ ds1216_write(ioaddr, magic); } static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct platform_device *pdev = to_platform_device(dev); struct ds1216_priv *priv = platform_get_drvdata(pdev); struct ds1216_regs regs; ds1216_switch_ds_to_clock(priv->ioaddr); ds1216_read(priv->ioaddr, (u8 *)®s); tm->tm_sec = bcd2bin(regs.sec); tm->tm_min = bcd2bin(regs.min); if (regs.hour & DS1216_HOUR_1224) { /* AM/PM mode */ tm->tm_hour = bcd2bin(regs.hour & 0x1f); if (regs.hour & DS1216_HOUR_AMPM) tm->tm_hour += 12; } else tm->tm_hour = bcd2bin(regs.hour & 0x3f); tm->tm_wday = (regs.wday & 7) - 1; tm->tm_mday = bcd2bin(regs.mday & 0x3f); tm->tm_mon = bcd2bin(regs.month & 0x1f); tm->tm_year = bcd2bin(regs.year); if (tm->tm_year < 70) tm->tm_year += 100; return rtc_valid_tm(tm); } static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct platform_device *pdev = to_platform_device(dev); struct ds1216_priv *priv = platform_get_drvdata(pdev); struct ds1216_regs regs; ds1216_switch_ds_to_clock(priv->ioaddr); ds1216_read(priv->ioaddr, (u8 *)®s); regs.tsec = 0; /* clear 0.1 and 0.01 seconds */ regs.sec = bin2bcd(tm->tm_sec); regs.min = bin2bcd(tm->tm_min); regs.hour &= DS1216_HOUR_1224; if (regs.hour && tm->tm_hour > 12) { regs.hour |= DS1216_HOUR_AMPM; tm->tm_hour -= 12; } regs.hour |= bin2bcd(tm->tm_hour); regs.wday &= ~7; regs.wday |= tm->tm_wday; regs.mday = bin2bcd(tm->tm_mday); regs.month = bin2bcd(tm->tm_mon); regs.year = bin2bcd(tm->tm_year % 100); ds1216_switch_ds_to_clock(priv->ioaddr); ds1216_write(priv->ioaddr, (u8 *)®s); return 0; } static const struct rtc_class_ops ds1216_rtc_ops = { .read_time = ds1216_rtc_read_time, .set_time = ds1216_rtc_set_time, }; static int __init ds1216_rtc_probe(struct platform_device *pdev) { struct resource *res; struct ds1216_priv *priv; u8 dummy[8]; priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; platform_set_drvdata(pdev, priv); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); priv->ioaddr = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(priv->ioaddr)) return PTR_ERR(priv->ioaddr); priv->rtc = devm_rtc_device_register(&pdev->dev, "ds1216", &ds1216_rtc_ops, THIS_MODULE); if (IS_ERR(priv->rtc)) return PTR_ERR(priv->rtc); /* dummy read to get clock into a known state */ ds1216_read(priv->ioaddr, dummy); return 0; } static struct platform_driver ds1216_rtc_platform_driver = { .driver = { .name = "rtc-ds1216", }, }; module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe); MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); MODULE_DESCRIPTION("DS1216 RTC driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:rtc-ds1216");