--- /dev/null
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ * Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
+ *
+ * RTC clock driver for the RTC part of the AB8500 Power management chip.
+ * Based on RTC clock driver for the AB3100 Analog Baseband Chip by
+ * Linus Walleij <linus.walleij@stericsson.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/mfd/ab8500.h>
+#include <linux/delay.h>
+
+#define AB8500_RTC_SOFF_STAT_REG 0x0F00
+#define AB8500_RTC_CC_CONF_REG 0x0F01
+#define AB8500_RTC_READ_REQ_REG 0x0F02
+#define AB8500_RTC_WATCH_TSECMID_REG 0x0F03
+#define AB8500_RTC_WATCH_TSECHI_REG 0x0F04
+#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x0F05
+#define AB8500_RTC_WATCH_TMIN_MID_REG 0x0F06
+#define AB8500_RTC_WATCH_TMIN_HI_REG 0x0F07
+#define AB8500_RTC_ALRM_MIN_LOW_REG 0x0F08
+#define AB8500_RTC_ALRM_MIN_MID_REG 0x0F09
+#define AB8500_RTC_ALRM_MIN_HI_REG 0x0F0A
+#define AB8500_RTC_STAT_REG 0x0F0B
+#define AB8500_RTC_BKUP_CHG_REG 0x0F0C
+#define AB8500_RTC_FORCE_BKUP_REG 0x0F0D
+#define AB8500_RTC_CALIB_REG 0x0F0E
+#define AB8500_RTC_SWITCH_STAT_REG 0x0F0F
+#define AB8500_REV_REG 0x1080
+
+/* RtcReadRequest bits */
+#define RTC_READ_REQUEST 0x01
+#define RTC_WRITE_REQUEST 0x02
+
+/* RtcCtrl bits */
+#define RTC_ALARM_ENA 0x04
+#define RTC_STATUS_DATA 0x01
+
+#define COUNTS_PER_SEC (0xF000 / 60)
+#define AB8500_RTC_EPOCH 2000
+
+static const unsigned long ab8500_rtc_time_regs[] = {
+ AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
+ AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
+ AB8500_RTC_WATCH_TSECMID_REG
+};
+
+static const unsigned long ab8500_rtc_alarm_regs[] = {
+ AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
+ AB8500_RTC_ALRM_MIN_LOW_REG
+};
+
+/* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
+static unsigned long get_elapsed_seconds(int year)
+{
+ unsigned long secs;
+ struct rtc_time tm = {
+ .tm_year = year - 1900,
+ .tm_mday = 1,
+ };
+
+ /*
+ * This function calculates secs from 1970 and not from
+ * 1900, even if we supply the offset from year 1900.
+ */
+ rtc_tm_to_time(&tm, &secs);
+ return secs;
+}
+
+static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
+ unsigned long timeout = jiffies + HZ;
+ int retval, i;
+ unsigned long mins, secs;
+ unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
+
+ /* Request a data read */
+ retval = ab8500_write(ab8500, AB8500_RTC_READ_REQ_REG,
+ RTC_READ_REQUEST);
+ if (retval < 0)
+ return retval;
+
+ /* Early AB8500 chips will not clear the rtc read request bit */
+ if (ab8500->revision == 0) {
+ msleep(1);
+ } else {
+ /* Wait for some cycles after enabling the rtc read in ab8500 */
+ while (time_before(jiffies, timeout)) {
+ retval = ab8500_read(ab8500, AB8500_RTC_READ_REQ_REG);
+ if (retval < 0)
+ return retval;
+
+ if (!(retval & RTC_READ_REQUEST))
+ break;
+
+ msleep(1);
+ }
+ }
+
+ /* Read the Watchtime registers */
+ for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
+ retval = ab8500_read(ab8500, ab8500_rtc_time_regs[i]);
+ if (retval < 0)
+ return retval;
+ buf[i] = retval;
+ }
+
+ mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
+
+ secs = (buf[3] << 8) | buf[4];
+ secs = secs / COUNTS_PER_SEC;
+ secs = secs + (mins * 60);
+
+ /* Add back the initially subtracted number of seconds */
+ secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
+
+ rtc_time_to_tm(secs, tm);
+ return rtc_valid_tm(tm);
+}
+
+static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
+ int retval, i;
+ unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
+ unsigned long no_secs, no_mins, secs = 0;
+
+ if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
+ dev_dbg(dev, "year should be equal to or greater than %d\n",
+ AB8500_RTC_EPOCH);
+ return -EINVAL;
+ }
+
+ /* Get the number of seconds since 1970 */
+ rtc_tm_to_time(tm, &secs);
+
+ /*
+ * Convert it to the number of seconds since 01-01-2000 00:00:00, since
+ * we only have a small counter in the RTC.
+ */
+ secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
+
+ no_mins = secs / 60;
+
+ no_secs = secs % 60;
+ /* Make the seconds count as per the RTC resolution */
+ no_secs = no_secs * COUNTS_PER_SEC;
+
+ buf[4] = no_secs & 0xFF;
+ buf[3] = (no_secs >> 8) & 0xFF;
+
+ buf[2] = no_mins & 0xFF;
+ buf[1] = (no_mins >> 8) & 0xFF;
+ buf[0] = (no_mins >> 16) & 0xFF;
+
+ for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
+ retval = ab8500_write(ab8500, ab8500_rtc_time_regs[i], buf[i]);
+ if (retval < 0)
+ return retval;
+ }
+
+ /* Request a data write */
+ return ab8500_write(ab8500, AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
+}
+
+static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
+ int retval, i;
+ int rtc_ctrl;
+ unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
+ unsigned long secs, mins;
+
+ /* Check if the alarm is enabled or not */
+ rtc_ctrl = ab8500_read(ab8500, AB8500_RTC_STAT_REG);
+ if (rtc_ctrl < 0)
+ return rtc_ctrl;
+
+ if (rtc_ctrl & RTC_ALARM_ENA)
+ alarm->enabled = 1;
+ else
+ alarm->enabled = 0;
+
+ alarm->pending = 0;
+
+ for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
+ retval = ab8500_read(ab8500, ab8500_rtc_alarm_regs[i]);
+ if (retval < 0)
+ return retval;
+ buf[i] = retval;
+ }
+
+ mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
+ secs = mins * 60;
+
+ /* Add back the initially subtracted number of seconds */
+ secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
+
+ rtc_time_to_tm(secs, &alarm->time);
+
+ return rtc_valid_tm(&alarm->time);
+}
+
+static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
+
+ return ab8500_set_bits(ab8500, AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
+ enabled ? RTC_ALARM_ENA : 0);
+}
+
+static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct ab8500 *ab8500 = dev_get_drvdata(dev->parent);
+ int retval, i;
+ unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
+ unsigned long mins, secs = 0;
+
+ if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
+ dev_dbg(dev, "year should be equal to or greater than %d\n",
+ AB8500_RTC_EPOCH);
+ return -EINVAL;
+ }
+
+ /* Get the number of seconds since 1970 */
+ rtc_tm_to_time(&alarm->time, &secs);
+
+ /*
+ * Convert it to the number of seconds since 01-01-2000 00:00:00, since
+ * we only have a small counter in the RTC.
+ */
+ secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
+
+ mins = secs / 60;
+
+ buf[2] = mins & 0xFF;
+ buf[1] = (mins >> 8) & 0xFF;
+ buf[0] = (mins >> 16) & 0xFF;
+
+ /* Set the alarm time */
+ for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
+ retval = ab8500_write(ab8500, ab8500_rtc_alarm_regs[i], buf[i]);
+ if (retval < 0)
+ return retval;
+ }
+
+ return ab8500_rtc_irq_enable(dev, alarm->enabled);
+}
+
+static irqreturn_t rtc_alarm_handler(int irq, void *data)
+{
+ struct rtc_device *rtc = data;
+ unsigned long events = RTC_IRQF | RTC_AF;
+
+ dev_dbg(&rtc->dev, "%s\n", __func__);
+ rtc_update_irq(rtc, 1, events);
+
+ return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops ab8500_rtc_ops = {
+ .read_time = ab8500_rtc_read_time,
+ .set_time = ab8500_rtc_set_time,
+ .read_alarm = ab8500_rtc_read_alarm,
+ .set_alarm = ab8500_rtc_set_alarm,
+ .alarm_irq_enable = ab8500_rtc_irq_enable,
+};
+
+static int __devinit ab8500_rtc_probe(struct platform_device *pdev)
+{
+ struct ab8500 *ab8500 = dev_get_drvdata(pdev->dev.parent);
+ int err;
+ struct rtc_device *rtc;
+ int rtc_ctrl;
+ int irq;
+
+ irq = platform_get_irq_byname(pdev, "ALARM");
+ if (irq < 0)
+ return irq;
+
+ /* For RTC supply test */
+ err = ab8500_set_bits(ab8500, AB8500_RTC_STAT_REG, RTC_STATUS_DATA,
+ RTC_STATUS_DATA);
+ if (err < 0)
+ return err;
+
+ /* Wait for reset by the PorRtc */
+ msleep(1);
+
+ rtc_ctrl = ab8500_read(ab8500, AB8500_RTC_STAT_REG);
+ if (rtc_ctrl < 0)
+ return rtc_ctrl;
+
+ /* Check if the RTC Supply fails */
+ if (!(rtc_ctrl & RTC_STATUS_DATA)) {
+ dev_err(&pdev->dev, "RTC supply failure\n");
+ return -ENODEV;
+ }
+
+ rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops,
+ THIS_MODULE);
+ if (IS_ERR(rtc)) {
+ dev_err(&pdev->dev, "Registration failed\n");
+ err = PTR_ERR(rtc);
+ return err;
+ }
+
+ err = request_threaded_irq(irq, NULL, rtc_alarm_handler, 0,
+ "ab8500-rtc", rtc);
+ if (err < 0) {
+ rtc_device_unregister(rtc);
+ return err;
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ return 0;
+}
+
+static int __devexit ab8500_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_device *rtc = platform_get_drvdata(pdev);
+ int irq = platform_get_irq_byname(pdev, "ALARM");
+
+ free_irq(irq, rtc);
+ rtc_device_unregister(rtc);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver ab8500_rtc_driver = {
+ .driver = {
+ .name = "ab8500-rtc",
+ .owner = THIS_MODULE,
+ },
+ .probe = ab8500_rtc_probe,
+ .remove = __devexit_p(ab8500_rtc_remove),
+};
+
+static int __init ab8500_rtc_init(void)
+{
+ return platform_driver_register(&ab8500_rtc_driver);
+}
+
+static void __exit ab8500_rtc_exit(void)
+{
+ platform_driver_unregister(&ab8500_rtc_driver);
+}
+
+module_init(ab8500_rtc_init);
+module_exit(ab8500_rtc_exit);
+MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
+MODULE_DESCRIPTION("AB8500 RTC Driver");
+MODULE_LICENSE("GPL v2");
projects / kernel / kernel-generic.git / commitdiff