rtc: AB8500 RTC driver
Virupax Sadashivpetimath [Wed, 26 May 2010 21:42:14 +0000 (14:42 -0700)]
Add a driver for the RTC on the AB8500 power management chip.  This is a
client of the AB8500 MFD driver.

Signed-off-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-ab8500.c [new file with mode: 0644]

index f159832..10ba12c 100644 (file)
@@ -611,6 +611,13 @@ config RTC_DRV_AB3100
          Select this to enable the ST-Ericsson AB3100 Mixed Signal IC RTC
          support. This chip contains a battery- and capacitor-backed RTC.
 
+config RTC_DRV_AB8500
+       tristate "ST-Ericsson AB8500 RTC"
+       depends on AB8500_CORE
+       help
+         Select this to enable the ST-Ericsson AB8500 power management IC RTC
+         support. This chip contains a battery- and capacitor-backed RTC.
+
 config RTC_DRV_NUC900
        tristate "NUC910/NUC920 RTC driver"
        depends on RTC_CLASS && ARCH_W90X900
index 245311a..5adbba7 100644 (file)
@@ -18,6 +18,7 @@ rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
 # Keep the list ordered.
 
 obj-$(CONFIG_RTC_DRV_AB3100)   += rtc-ab3100.o
+obj-$(CONFIG_RTC_DRV_AB8500)   += rtc-ab8500.o
 obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_AT91SAM9) += rtc-at91sam9.o
diff --git a/drivers/rtc/rtc-ab8500.c b/drivers/rtc/rtc-ab8500.c
new file mode 100644 (file)
index 0000000..2fda031
--- /dev/null
@@ -0,0 +1,363 @@
+/*
+ * 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");