--- /dev/null
+/**
+ * drivers/cbus/retu-rtc.c
+ *
+ * Support for Retu RTC
+ *
+ * Copyright (C) 2004, 2005 Nokia Corporation
+ *
+ * Written by Paul Mundt <paul.mundt@nokia.com> and
+ * Igor Stoppa <igor.stoppa@nokia.com>
+ *
+ * The Retu RTC is essentially a partial read-only RTC that gives us Retu's
+ * idea of what time actually is. It's left as a userspace excercise to map
+ * this back to time in the real world and ensure that calibration settings
+ * are sane to compensate for any horrible drift (on account of not being able
+ * to set the clock to anything).
+ *
+ * Days are semi-writeable. Namely, Retu will only track 255 days for us
+ * consecutively, after which the counter is explicitly stuck at 255 until
+ * someone comes along and clears it with a write. In the event that no one
+ * comes along and clears it, we no longer have any idea what day it is.
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+#include "cbus.h"
+#include "retu.h"
+
+static struct mutex retu_rtc_mutex;
+static u16 retu_rtc_alarm_expired;
+static u16 retu_rtc_reset_occurred;
+
+static DECLARE_COMPLETION(retu_rtc_exited);
+static DECLARE_COMPLETION(retu_rtc_sync);
+
+static void retu_rtc_barrier(void);
+
+static void retu_rtc_device_release(struct device *dev)
+{
+ complete(&retu_rtc_exited);
+}
+
+static ssize_t retu_rtc_time_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ u16 dsr, hmr, dsr2;
+
+ mutex_lock(&retu_rtc_mutex);
+
+ do {
+ u16 dummy;
+
+ /*
+ * Not being in_interrupt() for a retu rtc IRQ, we need to
+ * read twice for consistency..
+ */
+ dummy = retu_read_reg(RETU_REG_RTCDSR);
+ dsr = retu_read_reg(RETU_REG_RTCDSR);
+
+ dummy = retu_read_reg(RETU_REG_RTCHMR);
+ hmr = retu_read_reg(RETU_REG_RTCHMR);
+
+ dummy = retu_read_reg(RETU_REG_RTCDSR);
+ dsr2 = retu_read_reg(RETU_REG_RTCDSR);
+ } while ((dsr != dsr2));
+
+ mutex_unlock(&retu_rtc_mutex);
+
+ /*
+ * Format a 32-bit date-string for userspace
+ *
+ * days | hours | minutes | seconds
+ *
+ * 8 bits for each.
+ *
+ * This mostly sucks because days and seconds are tracked in RTCDSR
+ * while hours and minutes are tracked in RTCHMR. And yes, there
+ * really are no words that can describe an 8 bit day register (or
+ * rather, none that will be reprinted here).
+ */
+ return sprintf(buf, "0x%08x\n", (((dsr >> 8) & 0xff) << 24) |
+ (((hmr >> 8) & 0x1f) << 16) |
+ ((hmr & 0x3f) << 8) | (dsr & 0x3f));
+}
+
+static ssize_t retu_rtc_time_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ mutex_lock(&retu_rtc_mutex);
+ /*
+ * Writing anything to the day counter forces it to 0
+ * The seconds counter would be cleared by resetting the minutes counter,
+ * however this won't happen, since we are using the hh:mm counters as
+ * a set of free running counters and the day counter as a multiple
+ * overflow holder.
+ */
+
+ /* Reset day counter, but keep Temperature Shutdown state */
+ retu_write_reg(RETU_REG_RTCDSR,
+ retu_read_reg(RETU_REG_RTCDSR) & (1 << 6));
+
+ mutex_unlock(&retu_rtc_mutex);
+
+ return count;
+}
+
+static DEVICE_ATTR(time, S_IRUGO | S_IWUSR, retu_rtc_time_show,
+ retu_rtc_time_store);
+
+
+static ssize_t retu_rtc_reset_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ /*
+ * Returns the status of the rtc
+ *
+ * 0: no reset has occurred or the status has been cleared
+ * 1: a reset has occurred
+ *
+ * RTC needs to be reset only when both main battery
+ * _AND_ backup battery are discharged
+ */
+ return sprintf(buf, "%u\n", retu_rtc_reset_occurred);
+}
+
+static void retu_rtc_do_reset(void)
+{
+ u16 ccr1;
+
+ ccr1 = retu_read_reg(RETU_REG_CC1);
+ /* RTC in reset */
+ retu_write_reg(RETU_REG_CC1, ccr1 | 0x0001);
+ /* RTC in normal operating mode */
+ retu_write_reg(RETU_REG_CC1, ccr1 & ~0x0001);
+
+ retu_rtc_barrier();
+ /* Disable alarm and RTC WD */
+ retu_write_reg(RETU_REG_RTCHMAR, 0x7f3f);
+ /* Set Calibration register to default value */
+ retu_write_reg(RETU_REG_RTCCALR, 0x00c0);
+
+ retu_rtc_alarm_expired = 0;
+ retu_rtc_reset_occurred = 1;
+}
+
+static ssize_t retu_rtc_reset_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned choice;
+
+ if(sscanf(buf, "%u", &choice) != 1)
+ return count;
+ mutex_lock(&retu_rtc_mutex);
+ if (choice == 0)
+ retu_rtc_reset_occurred = 0;
+ else if (choice == 1)
+ retu_rtc_do_reset();
+ mutex_unlock(&retu_rtc_mutex);
+ return count;
+}
+
+static DEVICE_ATTR(reset, S_IRUGO | S_IWUSR, retu_rtc_reset_show,
+ retu_rtc_reset_store);
+
+static ssize_t retu_rtc_alarm_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ u16 chmar;
+ ssize_t retval;
+
+ mutex_lock(&retu_rtc_mutex);
+ /*
+ * Format a 16-bit date-string for userspace
+ *
+ * hours | minutes
+ * 8 bits for each.
+ */
+ chmar = retu_read_reg(RETU_REG_RTCHMAR);
+ /* No shifting needed, only masking unrelated bits */
+ retval = sprintf(buf, "0x%04x\n", chmar & 0x1f3f);
+ mutex_unlock(&retu_rtc_mutex);
+
+ return retval;
+}
+
+static ssize_t retu_rtc_alarm_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ u16 chmar;
+ unsigned alrm;
+ unsigned hours;
+ unsigned minutes;
+
+ mutex_lock(&retu_rtc_mutex);
+
+ if(sscanf(buf, "%x", &alrm) != 1)
+ return count;
+ hours = (alrm >> 8) & 0x001f;
+ minutes = (alrm >> 0) & 0x003f;
+ if ((hours < 24 && minutes < 60) || (hours == 24 && minutes == 60)) {
+ /*
+ * OK, the time format for the alarm is valid (including the
+ * disabling values)
+ */
+ /* Keeps the RTC watchdog status */
+ chmar = retu_read_reg(RETU_REG_RTCHMAR) & 0x6000;
+ chmar |= alrm & 0x1f3f; /* Stores the requested alarm */
+ retu_rtc_barrier();
+ retu_write_reg(RETU_REG_RTCHMAR, chmar);
+ /* If the alarm is being disabled */
+ if (hours == 24 && minutes == 60) {
+ /* disable the interrupt */
+ retu_disable_irq(RETU_INT_RTCA);
+ retu_rtc_alarm_expired = 0;
+ } else
+ /* enable the interrupt */
+ retu_enable_irq(RETU_INT_RTCA);
+ }
+ mutex_unlock(&retu_rtc_mutex);
+
+ return count;
+}
+
+static DEVICE_ATTR(alarm, S_IRUGO | S_IWUSR, retu_rtc_alarm_show,
+ retu_rtc_alarm_store);
+
+static ssize_t retu_rtc_alarm_expired_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ ssize_t retval;
+
+ retval = sprintf(buf, "%u\n", retu_rtc_alarm_expired);
+
+ return retval;
+}
+
+static ssize_t retu_rtc_alarm_expired_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ retu_rtc_alarm_expired = 0;
+
+ return count;
+}
+
+static DEVICE_ATTR(alarm_expired, S_IRUGO | S_IWUSR, retu_rtc_alarm_expired_show,
+ retu_rtc_alarm_expired_store);
+
+
+static ssize_t retu_rtc_cal_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ u16 rtccalr1;
+
+ mutex_lock(&retu_rtc_mutex);
+ rtccalr1 = retu_read_reg(RETU_REG_RTCCALR);
+ mutex_unlock(&retu_rtc_mutex);
+
+ /*
+ * Shows the status of the Calibration Register.
+ *
+ * Default, after power loss: 0x0000
+ * Default, for R&D: 0x00C0
+ * Default, for factory: 0x00??
+ *
+ */
+ return sprintf(buf, "0x%04x\n", rtccalr1 & 0x00ff);
+}
+
+static ssize_t retu_rtc_cal_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned calibration_value;
+
+ if (sscanf(buf, "%x", &calibration_value) != 1)
+ return count;
+
+ mutex_lock(&retu_rtc_mutex);
+ retu_rtc_barrier();
+ retu_write_reg(RETU_REG_RTCCALR, calibration_value & 0x00ff);
+ mutex_unlock(&retu_rtc_mutex);
+
+ return count;
+}
+
+static DEVICE_ATTR(cal, S_IRUGO | S_IWUSR, retu_rtc_cal_show,
+ retu_rtc_cal_store);
+
+static struct platform_device retu_rtc_device;
+
+static void retu_rtca_disable(void)
+{
+ retu_disable_irq(RETU_INT_RTCA);
+ retu_rtc_alarm_expired = 1;
+ retu_rtc_barrier();
+ retu_write_reg(RETU_REG_RTCHMAR, (24 << 8) | 60);
+}
+
+static void retu_rtca_expired(struct work_struct *unused)
+{
+ retu_rtca_disable();
+ sysfs_notify(&retu_rtc_device.dev.kobj, NULL, "alarm_expired");
+}
+
+DECLARE_WORK(retu_rtca_work, retu_rtca_expired);
+
+/*
+ * RTCHMR RTCHMAR RTCCAL must be accessed within 0.9 s since the seconds
+ * interrupt has been signaled in the IDR register
+ */
+static void retu_rtcs_interrupt(unsigned long unused)
+{
+ retu_ack_irq(RETU_INT_RTCS);
+ complete_all(&retu_rtc_sync);
+}
+
+static void retu_rtca_interrupt(unsigned long unused)
+{
+ retu_ack_irq(RETU_INT_RTCA);
+ schedule_work(&retu_rtca_work);
+}
+
+static int retu_rtc_init_irq(void)
+{
+ int ret;
+
+ ret = retu_request_irq(RETU_INT_RTCS, retu_rtcs_interrupt, 0, "RTCS");
+ if (ret != 0)
+ return ret;
+ /*
+ * We will take care of enabling and disabling the interrupt
+ * elsewhere, so leave it off by default..
+ */
+ retu_disable_irq(RETU_INT_RTCS);
+
+ ret = retu_request_irq(RETU_INT_RTCA, retu_rtca_interrupt, 0, "RTCA");
+ if (ret != 0) {
+ retu_free_irq(RETU_INT_RTCS);
+ return ret;
+ }
+ retu_disable_irq(RETU_INT_RTCA);
+
+ return 0;
+}
+
+
+static int __devinit retu_rtc_probe(struct device *dev)
+{
+ int r;
+
+ retu_rtc_alarm_expired = retu_read_reg(RETU_REG_IDR) &
+ (0x1 << RETU_INT_RTCA);
+
+ if ((r = retu_rtc_init_irq()) != 0)
+ return r;
+
+ mutex_init(&retu_rtc_mutex);
+
+ /* If the calibration register is zero, we've probably lost
+ * power */
+ if (retu_read_reg(RETU_REG_RTCCALR) & 0x00ff)
+ retu_rtc_reset_occurred = 0;
+ else
+ retu_rtc_do_reset();
+
+ if ((r = device_create_file(dev, &dev_attr_time)) != 0)
+ return r;
+ else if ((r = device_create_file(dev, &dev_attr_reset)) != 0)
+ goto err_unregister_time;
+ else if ((r = device_create_file(dev, &dev_attr_alarm)) != 0)
+ goto err_unregister_reset;
+ else if ((r = device_create_file(dev, &dev_attr_alarm_expired)) != 0)
+ goto err_unregister_alarm;
+ else if ((r = device_create_file(dev, &dev_attr_cal)) != 0)
+ goto err_unregister_alarm_expired;
+ else
+ return r;
+
+err_unregister_alarm_expired:
+ device_remove_file(dev, &dev_attr_alarm_expired);
+err_unregister_alarm:
+ device_remove_file(dev, &dev_attr_alarm);
+err_unregister_reset:
+ device_remove_file(dev, &dev_attr_reset);
+err_unregister_time:
+ device_remove_file(dev, &dev_attr_time);
+ return r;
+}
+
+static int __devexit retu_rtc_remove(struct device *dev)
+{
+ retu_disable_irq(RETU_INT_RTCS);
+ retu_free_irq(RETU_INT_RTCS);
+ retu_free_irq(RETU_INT_RTCA);
+ device_remove_file(dev, &dev_attr_cal);
+ device_remove_file(dev, &dev_attr_alarm_expired);
+ device_remove_file(dev, &dev_attr_alarm);
+ device_remove_file(dev, &dev_attr_reset);
+ device_remove_file(dev, &dev_attr_time);
+ return 0;
+}
+
+static struct device_driver retu_rtc_driver = {
+ .name = "retu-rtc",
+ .bus = &platform_bus_type,
+ .probe = retu_rtc_probe,
+ .remove = __devexit_p(retu_rtc_remove),
+};
+
+static struct platform_device retu_rtc_device = {
+ .name = "retu-rtc",
+ .id = -1,
+ .dev = {
+ .release = retu_rtc_device_release,
+ },
+};
+
+/* This function provides syncronization with the RTCS interrupt handler */
+static void retu_rtc_barrier(void)
+{
+ INIT_COMPLETION(retu_rtc_sync);
+ retu_ack_irq(RETU_INT_RTCS);
+ retu_enable_irq(RETU_INT_RTCS);
+ wait_for_completion(&retu_rtc_sync);
+ retu_disable_irq(RETU_INT_RTCS);
+}
+
+static int __init retu_rtc_init(void)
+{
+ int ret;
+
+ init_completion(&retu_rtc_exited);
+
+ if ((ret = driver_register(&retu_rtc_driver)) != 0)
+ return ret;
+
+ if ((ret = platform_device_register(&retu_rtc_device)) != 0)
+ goto err_unregister_driver;
+
+ return 0;
+
+err_unregister_driver:
+ driver_unregister(&retu_rtc_driver);
+ return ret;
+}
+
+static void __exit retu_rtc_exit(void)
+{
+ platform_device_unregister(&retu_rtc_device);
+ driver_unregister(&retu_rtc_driver);
+
+ wait_for_completion(&retu_rtc_exited);
+}
+
+module_init(retu_rtc_init);
+module_exit(retu_rtc_exit);
+
+MODULE_DESCRIPTION("Retu RTC");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul Mundt and Igor Stoppa");
projects / linux-2.6-omap-h63xx.git / blobdiff