--- /dev/null
+/*
+ * 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");
projects / linux-2.6 / commitdiff