diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1216.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1216.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1216.c b/drivers/rtc/rtc-ds1216.c new file mode 100644 index 00000000000..83efb88f8f2 --- /dev/null +++ b/drivers/rtc/rtc-ds1216.c @@ -0,0 +1,226 @@ +/* + * 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> + +#define DRV_VERSION "0.1" + +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; + size_t size; + unsigned long baseaddr; +}; + +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 0; +} + +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 __devinit ds1216_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + struct resource *res; + struct ds1216_priv *priv; + int ret = 0; + u8 dummy[8]; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + priv = kzalloc(sizeof *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->ioaddr = ioremap(priv->baseaddr, priv->size); + if (!priv->ioaddr) { + ret = -ENOMEM; + goto out; + } + rtc = rtc_device_register("ds1216", &pdev->dev, + &ds1216_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + ret = PTR_ERR(rtc); + goto out; + } + priv->rtc = rtc; + platform_set_drvdata(pdev, priv); + + /* dummy read to get clock into a known state */ + ds1216_read(priv->ioaddr, dummy); + return 0; + +out: + if (priv->rtc) + rtc_device_unregister(priv->rtc); + if (priv->ioaddr) + iounmap(priv->ioaddr); + if (priv->baseaddr) + release_mem_region(priv->baseaddr, priv->size); + kfree(priv); + return ret; +} + +static int __devexit ds1216_rtc_remove(struct platform_device *pdev) +{ + struct ds1216_priv *priv = platform_get_drvdata(pdev); + + rtc_device_unregister(priv->rtc); + iounmap(priv->ioaddr); + release_mem_region(priv->baseaddr, priv->size); + kfree(priv); + return 0; +} + +static struct platform_driver ds1216_rtc_platform_driver = { + .driver = { + .name = "rtc-ds1216", + .owner = THIS_MODULE, + }, + .probe = ds1216_rtc_probe, + .remove = __devexit_p(ds1216_rtc_remove), +}; + +static int __init ds1216_rtc_init(void) +{ + return platform_driver_register(&ds1216_rtc_platform_driver); +} + +static void __exit ds1216_rtc_exit(void) +{ + platform_driver_unregister(&ds1216_rtc_platform_driver); +} + +MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); +MODULE_DESCRIPTION("DS1216 RTC driver"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(DRV_VERSION); + +module_init(ds1216_rtc_init); +module_exit(ds1216_rtc_exit); |