diff options
| -rw-r--r-- | drivers/rtc/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/rtc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rtc/rtc-ds1305.c | 847 | ||||
| -rw-r--r-- | include/linux/spi/ds1305.h | 35 |
4 files changed, 893 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index beffb83..90ab738 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -282,6 +282,16 @@ config RTC_DRV_M41T94 This driver can also be built as a module. If so, the module will be called rtc-m41t94. +config RTC_DRV_DS1305 + tristate "Dallas/Maxim DS1305/DS1306" + help + Select this driver to get support for the Dallas/Maxim DS1305 + and DS1306 real time clock chips. These support a trickle + charger, alarms, and NVRAM in addition to the clock. + + This driver can also be built as a module. If so, the module + will be called rtc-ds1305. + config RTC_DRV_MAX6902 tristate "Maxim MAX6902" help diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index b0e1af5..18622ef 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -24,6 +24,7 @@ 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_DS1302) += rtc-ds1302.o +obj-$(CONFIG_RTC_DRV_DS1305) += rtc-ds1305.o obj-$(CONFIG_RTC_DRV_DS1307) += rtc-ds1307.o obj-$(CONFIG_RTC_DRV_DS1374) += rtc-ds1374.o obj-$(CONFIG_RTC_DRV_DS1511) += rtc-ds1511.o diff --git a/drivers/rtc/rtc-ds1305.c b/drivers/rtc/rtc-ds1305.c new file mode 100644 index 0000000..b91d02a --- /dev/null +++ b/drivers/rtc/rtc-ds1305.c @@ -0,0 +1,847 @@ +/* + * rtc-ds1305.c -- driver for DS1305 and DS1306 SPI RTC chips + * + * Copyright (C) 2008 David Brownell + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/bcd.h> +#include <linux/rtc.h> +#include <linux/workqueue.h> + +#include <linux/spi/spi.h> +#include <linux/spi/ds1305.h> + + +/* + * Registers ... mask DS1305_WRITE into register address to write, + * otherwise you're reading it. All non-bitmask values are BCD. + */ +#define DS1305_WRITE 0x80 + + +/* RTC date/time ... the main special cases are that we: + * - Need fancy "hours" encoding in 12hour mode + * - Don't rely on the "day-of-week" field (or tm_wday) + * - Are a 21st-century clock (2000 <= year < 2100) + */ +#define DS1305_RTC_LEN 7 /* bytes for RTC regs */ + +#define DS1305_SEC 0x00 /* register addresses */ +#define DS1305_MIN 0x01 +#define DS1305_HOUR 0x02 +# define DS1305_HR_12 0x40 /* set == 12 hr mode */ +# define DS1305_HR_PM 0x20 /* set == PM (12hr mode) */ +#define DS1305_WDAY 0x03 +#define DS1305_MDAY 0x04 +#define DS1305_MON 0x05 +#define DS1305_YEAR 0x06 + + +/* The two alarms have only sec/min/hour/wday fields (ALM_LEN). + * DS1305_ALM_DISABLE disables a match field (some combos are bad). + * + * NOTE that since we don't use WDAY, we limit ourselves to alarms + * only one day into the future (vs potentially up to a week). + * + * NOTE ALSO that while we could generate once-a-second IRQs (UIE), we + * don't currently support them. We'd either need to do it only when + * no alarm is pending (not the standard model), or to use the second + * alarm (implying that this is a DS1305 not DS1306, *and* that either + * it's wired up a second IRQ we know, or that INTCN is set) + */ +#define DS1305_ALM_LEN 4 /* bytes for ALM regs */ +#define DS1305_ALM_DISABLE 0x80 + +#define DS1305_ALM0(r) (0x07 + (r)) /* register addresses */ +#define DS1305_ALM1(r) (0x0b + (r)) + + +/* three control registers */ +#define DS1305_CONTROL_LEN 3 /* bytes of control regs */ + +#define DS1305_CONTROL 0x0f /* register addresses */ +# define DS1305_nEOSC 0x80 /* low enables oscillator */ +# define DS1305_WP 0x40 /* write protect */ +# define DS1305_INTCN 0x04 /* clear == only int0 used */ +# define DS1306_1HZ 0x04 /* enable 1Hz output */ +# define DS1305_AEI1 0x02 /* enable ALM1 IRQ */ +# define DS1305_AEI0 0x01 /* enable ALM0 IRQ */ +#define DS1305_STATUS 0x10 +/* status has just AEIx bits, mirrored as IRQFx */ +#define DS1305_TRICKLE 0x11 +/* trickle bits are defined in <linux/spi/ds1305.h> */ + +/* a bunch of NVRAM */ +#define DS1305_NVRAM_LEN 96 /* bytes of NVRAM */ + +#define DS1305_NVRAM 0x20 /* register addresses */ + + +struct ds1305 { + struct spi_device *spi; + struct rtc_device *rtc; + + struct work_struct work; + + unsigned long flags; +#define FLAG_EXITING 0 + + bool hr12; + u8 ctrl[DS1305_CONTROL_LEN]; +}; + + +/*----------------------------------------------------------------------*/ + +/* + * Utilities ... tolerate 12-hour AM/PM notation in case of non-Linux + * software (like a bootloader) which may require it. + */ + +static unsigned bcd2hour(u8 bcd) +{ + if (bcd & DS1305_HR_12) { + unsigned hour = 0; + + bcd &= ~DS1305_HR_12; + if (bcd & DS1305_HR_PM) { + hour = 12; + bcd &= ~DS1305_HR_PM; + } + hour += BCD2BIN(bcd); + return hour - 1; + } + return BCD2BIN(bcd); +} + +static u8 hour2bcd(bool hr12, int hour) +{ + if (hr12) { + hour++; + if (hour <= 12) + return DS1305_HR_12 | BIN2BCD(hour); + hour -= 12; + return DS1305_HR_12 | DS1305_HR_PM | BIN2BCD(hour); + } + return BIN2BCD(hour); +} + +/*----------------------------------------------------------------------*/ + +/* + * Interface to RTC framework + */ + +#ifdef CONFIG_RTC_INTF_DEV + +/* + * Context: caller holds rtc->ops_lock (to protect ds1305->ctrl) + */ +static int ds1305_ioctl(struct device *dev, unsigned cmd, unsigned long arg) +{ + struct ds1305 *ds1305 = dev_get_drvdata(dev); + u8 buf[2]; + int status = -ENOIOCTLCMD; + + buf[0] = DS1305_WRITE | DS1305_CONTROL; + buf[1] = ds1305->ctrl[0]; + + switch (cmd) { + case RTC_AIE_OFF: + status = 0; + if (!(buf[1] & DS1305_AEI0)) + goto done; + buf[1] &= ~DS1305_AEI0; + break; + + case RTC_AIE_ON: + status = 0; + if (ds1305->ctrl[0] & DS1305_AEI0) + goto done; + buf[1] |= DS1305_AEI0; + break; + } + if (status == 0) { + status = spi_write_then_read(ds1305->spi, buf, sizeof buf, + NULL, 0); + if (status >= 0) + ds1305->ctrl[0] = buf[1]; + } + +done: + return status; +} + +#else +#define ds1305_ioctl NULL +#endif + +/* + * Get/set of date and time is pretty normal. + */ + +static int ds1305_get_time(struct device *dev, struct rtc_time *time) +{ + struct ds1305 *ds1305 = dev_get_drvdata(dev); + u8 addr = DS1305_SEC; + u8 buf[DS1305_RTC_LEN]; + int status; + + /* Use write-then-read to get all the date/time registers + * since dma from stack is nonportable + */ + status = spi_write_then_read(ds1305->spi, &addr, sizeof addr, + buf, sizeof buf); + if (status < 0) + return status; + + dev_vdbg(dev, "%s: %02x %02x %02x, %02x %02x %02x %02x\n", + "read", buf[0], buf[1], buf[2], buf[3], + buf[4], buf[5], buf[6]); + + /* Decode the registers */ + time->tm_sec = BCD2BIN(buf[DS1305_SEC]); + time->tm_min = BCD2BIN(buf[DS1305_MIN]); + time->tm_hour = bcd2hour(buf[DS1305_HOUR]); + time->tm_wday = buf[DS1305_WDAY] - 1; + time->tm_mday = BCD2BIN(buf[DS1305_MDAY]); + time->tm_mon = BCD2BIN(buf[DS1305_MON]) - 1; + time->tm_year = BCD2BIN(buf[DS1305_YEAR]) + 100; + + dev_vdbg(dev, "%s secs=%d, mins=%d, " + "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", + "read", time->tm_sec, time->tm_min, + time->tm_hour, time->tm_mday, + time->tm_mon, time->tm_year, time->tm_wday); + + /* Time may not be set */ + return rtc_valid_tm(time); +} + +static int ds1305_set_time(struct device *dev, struct rtc_time *time) +{ + struct ds1305 *ds1305 = dev_get_drvdata(dev); + u8 buf[1 + DS1305_RTC_LEN]; + u8 *bp = buf; + + dev_vdbg(dev, "%s secs=%d, mins=%d, " + "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", + "write", time->tm_sec, time->tm_min, + time->tm_hour, time->tm_mday, + time->tm_mon, time->tm_year, time->tm_wday); + + /* Write registers starting at the first time/date address. */ + *bp++ = DS1305_WRITE | DS1305_SEC; + + *bp++ = BIN2BCD(time->tm_sec); + *bp++ = BIN2BCD(time->tm_min); + *bp++ = hour2bcd(ds1305->hr12, time->tm_hour); + *bp++ = (time->tm_wday < 7) ? (time->tm_wday + 1) : 1; + *bp++ = BIN2BCD(time->tm_mday); + *bp++ = BIN2BCD(time->tm_mon + 1); + *bp++ = BIN2BCD(time->tm_year - 100); + + dev_dbg(dev, "%s: %02x %02x %02x, %02x %02x %02x %02x\n", + "write", buf[1], buf[2], buf[3], + buf[4], buf[5], buf[6], buf[7]); + + /* use write-then-read since dma from stack is nonportable */ + return spi_write_then_read(ds1305->spi, buf, sizeof buf, + NULL, 0); +} + +/* + * Get/set of alarm is a bit funky: + * + * - First there's the inherent raciness of getting the (partitioned) + * status of an alarm that could trigger while we're reading parts + * of that status. + * + * - Second there's its limited range (we could increase it a bit by + * relying on WDAY), which means it will easily roll over. + * + * - Third there's the choice of two alarms and alarm signals. + * Here we use ALM0 and expect that nINT0 (open drain) is used; + * that's the only real option for DS1306 runtime alarms, and is + * natural on DS1305. + * + * - Fourth, there's also ALM1, and a second interrupt signal: + * + On DS1305 ALM1 uses nINT1 (when INTCN=1) else nINT0; + * + On DS1306 ALM1 only uses INT1 (an active high pulse) + * and it won't work when VCC1 is active. + * + * So to be most general, we should probably set both alarms to the + * same value, letting ALM1 be the wakeup event source on DS1306 + * and handling several wiring options on DS1305. + * + * - Fifth, we support the polled mode (as well as possible; why not?) + * even when no interrupt line is wired to an IRQ. + */ + +/* + * Context: caller holds rtc->ops_lock (to protect ds1305->ctrl) + */ +static int ds1305_get_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct ds1305 *ds1305 = dev_get_drvdata(dev); + struct spi_device *spi = ds1305->spi; + u8 addr; + int status; + u8 buf[DS1305_ALM_LEN]; + + /* Refresh control register cache BEFORE reading ALM0 registers, + * since reading alarm registers acks any pending IRQ. That + * makes returning "pending" status a bit of a lie, but that bit + * of EFI status is at best fragile anyway (given IRQ handlers). + */ + addr = DS1305_CONTROL; + status = spi_write_then_read(spi, &addr, sizeof addr, + ds1305->ctrl, sizeof ds1305->ctrl); + if (status < 0) + return status; + + alm->enabled = !!(ds1305->ctrl[0] & DS1305_AEI0); + alm->pending = !!(ds1305->ctrl[1] & DS1305_AEI0); + + /* get and check ALM0 registers */ + addr = DS1305_ALM0(DS1305_SEC); + status = spi_write_then_read(spi, &addr, sizeof addr, + buf, sizeof buf); + if (status < 0) + return status; + + dev_vdbg(dev, "%s: %02x %02x %02x %02x\n", + "alm0 read", buf[DS1305_SEC], buf[DS1305_MIN], + buf[DS1305_HOUR], buf[DS1305_WDAY]); + + if ((DS1305_ALM_DISABLE & buf[DS1305_SEC]) + || (DS1305_ALM_DISABLE & buf[DS1305_MIN]) + || (DS1305_ALM_DISABLE & buf[DS1305_HOUR])) + return -EIO; + + /* Stuff these values into alm->time and let RTC framework code + * fill in the rest ... and also handle rollover to tomorrow when + * that's needed. + */ + alm->time.tm_sec = BCD2BIN(buf[DS1305_SEC]); + alm->time.tm_min = BCD2BIN(buf[DS1305_MIN]); + alm->time.tm_hour = bcd2hour(buf[DS1305_HOUR]); + alm->time.tm_mday = -1; + alm->time.tm_mon = -1; + alm->time.tm_year = -1; + /* next three fields are unused by Linux */ + alm->time.tm_wday = -1; + alm->time.tm_mday = -1; + alm->time.tm_isdst = -1; + + return 0; +} + +/* + * Context: caller holds rtc->ops_lock (to protect ds1305->ctrl) + */ +static int ds1305_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct ds1305 *ds1305 = dev_get_drvdata(dev); + struct spi_device *spi = ds1305->spi; + unsigned long now, later; + struct rtc_time tm; + int status; + u8 buf[1 + DS1305_ALM_LEN]; + + /* convert desired alarm to time_t */ + status = rtc_tm_to_time(&alm->time, &later); + if (status < 0) + return status; + + /* Read current time as time_t */ + status = ds1305_get_time(dev, &tm); + if (status < 0) + return status; + status = rtc_tm_to_time(&tm, &now); + if (status < 0) + return status; + + /* make sure alarm fires within the next 24 hours */ + if (later <= now) + return -EINVAL; + if ((later - now) > 24 * 60 * 60) + return -EDOM; + + /* disable alarm if needed */ + if (ds1305->ctrl[0] & DS1305_AEI0) { + ds1305->ctrl[0] &= ~DS1305_AEI0; + + buf[0] = DS1305_WRITE | DS1305_CONTROL; + buf[1] = ds1305->ctrl[0]; + status = spi_write_then_read(ds1305->spi, buf, 2, NULL, 0); + if (status < 0) + return status; + } + + /* write alarm */ + buf[0] = DS1305_WRITE | DS1305_ALM0(DS1305_SEC); + buf[1 + DS1305_SEC] = BIN2BCD(alm->time.tm_sec); + buf[1 + DS1305_MIN] = BIN2BCD(alm->time.tm_min); + buf[1 + DS1305_HOUR] = hour2bcd(ds1305->hr12, alm->time.tm_hour); + buf[1 + DS1305_WDAY] = DS1305_ALM_DISABLE; + + dev_dbg(dev, "%s: %02x %02x %02x %02x\n", + "alm0 write", buf[1 + DS1305_SEC], buf[1 + DS1305_MIN], + buf[1 + DS1305_HOUR], buf[1 + DS1305_WDAY]); + + status = spi_write_then_read(spi, buf, sizeof buf, NULL, 0); + if (status < 0) + return status; + + /* enable alarm if requested */ + if (alm->enabled) { + ds1305->ctrl[0] |= DS1305_AEI0; + + buf[0] = DS1305_WRITE | DS1305_CONTROL; + buf[1] = ds1305->ctrl[0]; + status = spi_write_then_read(ds1305->spi, buf, 2, NULL, 0); + } + + return status; +} + +#ifdef CONFIG_PROC_FS + +static int ds1305_proc(struct device *dev, struct seq_file *seq) +{ + struct ds1305 *ds1305 = dev_get_drvdata(dev); + char *diodes = "no"; + char *resistors = ""; + + /* ctrl[2] is treated as read-only; no locking needed */ + if ((ds1305->ctrl[2] & 0xf0) == DS1305_TRICKLE_MAGIC) { + switch (ds1305->ctrl[2] & 0x0c) { + case DS1305_TRICKLE_DS2: + diodes = "2 diodes, "; + break; + case DS1305_TRICKLE_DS1: + diodes = "1 diode, "; + break; + default: + goto done; + } + switch (ds1305->ctrl[2] & 0x03) { + case DS1305_TRICKLE_2K: + resistors = "2k Ohm"; + break; + case DS1305_TRICKLE_4K: + resistors = "4k Ohm"; + break; + case DS1305_TRICKLE_8K: + resistors = "8k Ohm"; + break; + default: + diodes = "no"; + break; + } + } + +done: + return seq_printf(seq, + "trickle_charge\t: %s%s\n", + diodes, resistors); +} + +#else +#define ds1305_proc NULL +#endif + +static const struct rtc_class_ops ds1305_ops = { + .ioctl = ds1305_ioctl, + .read_time = ds1305_get_time, + .set_time = ds1305_set_time, + .read_alarm = ds1305_get_alarm, + .set_alarm = ds1305_set_alarm, + .proc = ds1305_proc, +}; + +static void ds1305_work(struct work_struct *work) +{ + struct ds1305 *ds1305 = container_of(work, struct ds1305, work); + struct mutex *lock = &ds1305->rtc->ops_lock; + struct spi_device *spi = ds1305->spi; + u8 buf[3]; + int status; + + /* lock to protect ds1305->ctrl */ + mutex_lock(lock); + + /* Disable the IRQ, and clear its status ... for now, we "know" + * that if more than one alarm is active, they're in sync. + * Note that reading ALM data registers also clears IRQ status. + */ + ds1305->ctrl[0] &= ~(DS1305_AEI1 | DS1305_AEI0); + ds1305->ctrl[1] = 0; + + buf[0] = DS1305_WRITE | DS1305_CONTROL; + buf[1] = ds1305->ctrl[0]; + buf[2] = 0; + + status = spi_write_then_read(spi, buf, sizeof buf, + NULL, 0); + if (status < 0) + dev_dbg(&spi->dev, "clear irq --> %d\n", status); + + mutex_unlock(lock); + + if (!test_bit(FLAG_EXITING, &ds1305->flags)) + enable_irq(spi->irq); + + /* rtc_update_irq() requires an IRQ-disabled context */ + local_irq_disable(); + rtc_update_irq(ds1305->rtc, 1, RTC_AF | RTC_IRQF); + local_irq_enable(); +} + +/* + * This "real" IRQ handler hands off to a workqueue mostly to allow + * mutex locking for ds1305->ctrl ... unlike I2C, we could issue async + * I/O requests in IRQ context (to clear the IRQ status). + */ +static irqreturn_t ds1305_irq(int irq, void *p) +{ + struct ds1305 *ds1305 = p; + + disable_irq(irq); + schedule_work(&ds1305->work); + return IRQ_HANDLED; +} + +/*----------------------------------------------------------------------*/ + +/* + * Interface for NVRAM + */ + +static void msg_init(struct spi_message *m, struct spi_transfer *x, + u8 *addr, size_t count, char *tx, char *rx) +{ + spi_message_init(m); + memset(x, 0, 2 * sizeof(*x)); + + x->tx_buf = addr; + x->len = 1; + spi_message_add_tail(x, m); + + x++; + + x->tx_buf = tx; + x->rx_buf = rx; + x->len = count; + spi_message_add_tail(x, m); +} + +static ssize_t +ds1305_nvram_read(struct kobject *kobj, struct bin_attribute *attr, + char *buf, loff_t off, size_t count) +{ + struct spi_device *spi; + u8 addr; + struct spi_message m; + struct spi_transfer x[2]; + int status; + + spi = container_of(kobj, struct spi_device, dev.kobj); + + if (unlikely(off >= DS1305_NVRAM_LEN)) + return 0; + if (count >= DS1305_NVRAM_LEN) + count = DS1305_NVRAM_LEN; + if ((off + count) > DS1305_NVRAM_LEN) + count = DS1305_NVRAM_LEN - off; + if (unlikely(!count)) + return count; + + addr = DS1305_NVRAM + off; + msg_init(&m, x, &addr, count, NULL, buf); + + status = spi_sync(spi, &m); + if (status < 0) + dev_err(&spi->dev, "nvram %s error %d\n", "read", status); + return (status < 0) ? status : count; +} + +static ssize_t +ds1305_nvram_write(struct kobject *kobj, struct bin_attribute *attr, + char *buf, loff_t off, size_t count) +{ + struct spi_device *spi; + u8 addr; + struct spi_message m; + struct spi_transfer x[2]; + int status; + + spi = container_of(kobj, struct spi_device, dev.kobj); + + if (unlikely(off >= DS1305_NVRAM_LEN)) + return -EFBIG; + if (count >= DS1305_NVRAM_LEN) + count = DS1305_NVRAM_LEN; + if ((off + count) > DS1305_NVRAM_LEN) + count = DS1305_NVRAM_LEN - off; + if (unlikely(!count)) + return count; + + addr = (DS1305_WRITE | DS1305_NVRAM) + off; + msg_init(&m, x, &addr, count, buf, NULL); + + status = spi_sync(spi, &m); + if (status < 0) + dev_err(&spi->dev, "nvram %s error %d\n", "write", status); + return (status < 0) ? status : count; +} + +static struct bin_attribute nvram = { + .attr.name = "nvram", + .attr.mode = S_IRUGO | S_IWUSR, + .attr.owner = THIS_MODULE, + .read = ds1305_nvram_read, + .write = ds1305_nvram_write, + .size = DS1305_NVRAM_LEN, +}; + +/*----------------------------------------------------------------------*/ + +/* + * Interface to SPI stack + */ + +static int __devinit ds1305_probe(struct spi_device *spi) +{ + struct ds1305 *ds1305; + struct rtc_device *rtc; + int status; + u8 addr, value; + struct ds1305_platform_data *pdata = spi->dev.platform_data; + bool write_ctrl = false; + + /* Sanity check board setup data. This may be hooked up + * in 3wire mode, but we don't care. Note that unless + * there's an inverter in place, this needs SPI_CS_HIGH! + */ + if ((spi->bits_per_word && spi->bits_per_word != 8) + || (spi->max_speed_hz > 2000000) + || !(spi->mode & SPI_CPHA)) + return -EINVAL; + + /* set up driver data */ + ds1305 = kzalloc(sizeof *ds1305, GFP_KERNEL); + if (!ds1305) + return -ENOMEM; + ds1305->spi = spi; + spi_set_drvdata(spi, ds1305); + + /* read and cache control registers */ + addr = DS1305_CONTROL; + status = spi_write_then_read(spi, &addr, sizeof addr, + ds1305->ctrl, sizeof ds1305->ctrl); + if (status < 0) { + dev_dbg(&spi->dev, "can't %s, %d\n", + "read", status); + goto fail0; + } + + dev_dbg(&spi->dev, "ctrl %s: %02x %02x %02x\n", + "read", ds1305->ctrl[0], + ds1305->ctrl[1], ds1305->ctrl[2]); + + /* Sanity check register values ... partially compensating for the + * fact that SPI has no device handshake. A pullup on MISO would + * make these tests fail; but not all systems will have one. If + * some register is neither 0x00 nor 0xff, a chip is likely there. + */ + if ((ds1305->ctrl[0] & 0x38) != 0 || (ds1305->ctrl[1] & 0xfc) != 0) { + dev_dbg(&spi->dev, "RTC chip is not present\n"); + status = -ENODEV; + goto fail0; + } + if (ds1305->ctrl[2] == 0) + dev_dbg(&spi->dev, "chip may not be present\n"); + + /* enable writes if needed ... if we were paranoid it would + * make sense to enable them only when absolutely necessary. + */ + if (ds1305->ctrl[0] & DS1305_WP) { + u8 buf[2]; + + ds1305->ctrl[0] &= ~DS1305_WP; + + buf[0] = DS1305_WRITE | DS1305_CONTROL; + buf[1] = ds1305->ctrl[0]; + status = spi_write_then_read(spi, buf, sizeof buf, NULL, 0); + + dev_dbg(&spi->dev, "clear WP --> %d\n", status); + if (status < 0) + goto fail0; + } + + /* on DS1305, maybe start oscillator; like most low power + * oscillators, it may take a second to stabilize + */ + if (ds1305->ctrl[0] & DS1305_nEOSC) { + ds1305->ctrl[0] &= ~DS1305_nEOSC; + write_ctrl = true; + dev_warn(&spi->dev, "SET TIME!\n"); + } + + /* ack any pending IRQs */ + if (ds1305->ctrl[1]) { + ds1305->ctrl[1] = 0; + write_ctrl = true; + } + + /* this may need one-time (re)init */ + if (pdata) { + /* maybe enable trickle charge */ + if (((ds1305->ctrl[2] & 0xf0) != DS1305_TRICKLE_MAGIC)) { + ds1305->ctrl[2] = DS1305_TRICKLE_MAGIC + | pdata->trickle; + write_ctrl = true; + } + + /* on DS1306, configure 1 Hz signal */ + if (pdata->is_ds1306) { + if (pdata->en_1hz) { + if (!(ds1305->ctrl[0] & DS1306_1HZ)) { + ds1305->ctrl[0] |= DS1306_1HZ; + write_ctrl = true; + } + } else { + if (ds1305->ctrl[0] & DS1306_1HZ) { + ds1305->ctrl[0] &= ~DS1306_1HZ; + write_ctrl = true; + } + } + } + } + + if (write_ctrl) { + u8 buf[4]; + + buf[0] = DS1305_WRITE | DS1305_CONTROL; + buf[1] = ds1305->ctrl[0]; + buf[2] = ds1305->ctrl[1]; + buf[3] = ds1305->ctrl[2]; + status = spi_write_then_read(spi, buf, sizeof buf, NULL, 0); + if (status < 0) { + dev_dbg(&spi->dev, "can't %s, %d\n", + "write", status); + goto fail0; + } + + dev_dbg(&spi->dev, "ctrl %s: %02x %02x %02x\n", + "write", ds1305->ctrl[0], + ds1305->ctrl[1], ds1305->ctrl[2]); + } + + /* see if non-Linux software set up AM/PM mode */ + addr = DS1305_HOUR; + status = spi_write_then_read(spi, &addr, sizeof addr, + &value, sizeof value); + if (status < 0) { + dev_dbg(&spi->dev, "read HOUR --> %d\n", status); + goto fail0; + } + + ds1305->hr12 = (DS1305_HR_12 & value) != 0; + if (ds1305->hr12) + dev_dbg(&spi->dev, "AM/PM\n"); + + /* register RTC ... from here on, ds1305->ctrl needs locking */ + rtc = rtc_device_register("ds1305", &spi->dev, + &ds1305_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + status = PTR_ERR(rtc); + dev_dbg(&spi->dev, "register rtc --> %d\n", status); + goto fail0; + } + ds1305->rtc = rtc; + + /* Maybe set up alarm IRQ; be ready to handle it triggering right + * away. NOTE that we don't share this. The signal is active low, + * and we can't ack it before a SPI message delay. We temporarily + * disable the IRQ until it's acked, which lets us work with more + * IRQ trigger modes (not all IRQ controllers can do falling edge). + */ + if (spi->irq) { + INIT_WORK(&ds1305->work, ds1305_work); + status = request_irq(spi->irq, ds1305_irq, + 0, dev_name(&rtc->dev), ds1305); + if (status < 0) { + dev_dbg(&spi->dev, "request_irq %d --> %d\n", + spi->irq, status); + goto fail1; + } + } + + /* export NVRAM */ + status = sysfs_create_bin_file(&spi->dev.kobj, &nvram); + if (status < 0) { + dev_dbg(&spi->dev, "register nvram --> %d\n", status); + goto fail2; + } + + return 0; + +fail2: + free_irq(spi->irq, ds1305); +fail1: + rtc_device_unregister(rtc); +fail0: + kfree(ds1305); + return status; +} + +static int __devexit ds1305_remove(struct spi_device *spi) +{ + struct ds1305 *ds1305 = spi_get_drvdata(spi); + + sysfs_remove_bin_file(&spi->dev.kobj, &nvram); + + /* carefully shut down irq and workqueue, if present */ + if (spi->irq) { + set_bit(FLAG_EXITING, &ds1305->flags); + free_irq(spi->irq, ds1305); + flush_scheduled_work(); + } + + rtc_device_unregister(ds1305->rtc); + spi_set_drvdata(spi, NULL); + kfree(ds1305); + return 0; +} + +static struct spi_driver ds1305_driver = { + .driver.name = "rtc-ds1305", + .driver.owner = THIS_MODULE, + .probe = ds1305_probe, + .remove = __devexit_p(ds1305_remove), + /* REVISIT add suspend/resume */ +}; + +static int __init ds1305_init(void) +{ + return spi_register_driver(&ds1305_driver); +} +module_init(ds1305_init); + +static void __exit ds1305_exit(void) +{ + spi_unregister_driver(&ds1305_driver); +} +module_exit(ds1305_exit); + +MODULE_DESCRIPTION("RTC driver for DS1305 and DS1306 chips"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/spi/ds1305.h b/include/linux/spi/ds1305.h new file mode 100644 index 0000000..287ec83 --- /dev/null +++ b/include/linux/spi/ds1305.h @@ -0,0 +1,35 @@ +#ifndef __LINUX_SPI_DS1305_H +#define __LINUX_SPI_DS1305_H + +/* + * One-time configuration for ds1305 and ds1306 RTC chips. + * + * Put a pointer to this in spi_board_info.platform_data if you want to + * be sure that Linux (re)initializes this as needed ... after losing + * backup power, and potentially on the first boot. + */ +struct ds1305_platform_data { + + /* Trickle charge configuration: it's OK to leave out the MAGIC + * bitmask; mask in either DS1 or DS2, and then one of 2K/4k/8K. + */ +#define DS1305_TRICKLE_MAGIC 0xa0 +#define DS1305_TRICKLE_DS2 0x08 /* two diodes */ +#define DS1305_TRICKLE_DS1 0x04 /* one diode */ +#define DS1305_TRICKLE_2K 0x01 /* 2 KOhm resistance */ +#define DS1305_TRICKLE_4K 0x02 /* 4 KOhm resistance */ +#define DS1305_TRICKLE_8K 0x03 /* 8 KOhm resistance */ + u8 trickle; + + /* set only on ds1306 parts */ + bool is_ds1306; + + /* ds1306 only: enable 1 Hz output */ + bool en_1hz; + + /* REVISIT: the driver currently expects nINT0 to be wired + * as the alarm IRQ. ALM1 may also need to be set up ... + */ +}; + +#endif /* __LINUX_SPI_DS1305_H */ |
