diff options
Diffstat (limited to 'drivers/rtc/rtc-ab8500.c')
| -rw-r--r-- | drivers/rtc/rtc-ab8500.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ab8500.c b/drivers/rtc/rtc-ab8500.c new file mode 100644 index 000000000000..2fda03125e55 --- /dev/null +++ b/drivers/rtc/rtc-ab8500.c @@ -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"); |