/* * 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/abx500.h> #include <linux/mfd/abx500/ab8500.h> #include <linux/delay.h> #include <linux/of.h> #define AB8500_RTC_SOFF_STAT_REG 0x00 #define AB8500_RTC_CC_CONF_REG 0x01 #define AB8500_RTC_READ_REQ_REG 0x02 #define AB8500_RTC_WATCH_TSECMID_REG 0x03 #define AB8500_RTC_WATCH_TSECHI_REG 0x04 #define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05 #define AB8500_RTC_WATCH_TMIN_MID_REG 0x06 #define AB8500_RTC_WATCH_TMIN_HI_REG 0x07 #define AB8500_RTC_ALRM_MIN_LOW_REG 0x08 #define AB8500_RTC_ALRM_MIN_MID_REG 0x09 #define AB8500_RTC_ALRM_MIN_HI_REG 0x0A #define AB8500_RTC_STAT_REG 0x0B #define AB8500_RTC_BKUP_CHG_REG 0x0C #define AB8500_RTC_FORCE_BKUP_REG 0x0D #define AB8500_RTC_CALIB_REG 0x0E #define AB8500_RTC_SWITCH_STAT_REG 0x0F /* 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 u8 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 u8 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) { unsigned long timeout = jiffies + HZ; int retval, i; unsigned long mins, secs; unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; u8 value; /* Request a data read */ retval = abx500_set_register_interruptible(dev, AB8500_RTC, 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 (abx500_get_chip_id(dev) == 0) { usleep_range(1000, 1000); } else { /* Wait for some cycles after enabling the rtc read in ab8500 */ while (time_before(jiffies, timeout)) { retval = abx500_get_register_interruptible(dev, AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value); if (retval < 0) return retval; if (!(value & RTC_READ_REQUEST)) break; usleep_range(1000, 5000); } } /* Read the Watchtime registers */ for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { retval = abx500_get_register_interruptible(dev, AB8500_RTC, ab8500_rtc_time_regs[i], &value); if (retval < 0) return retval; buf[i] = value; } 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) { 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 = abx500_set_register_interruptible(dev, AB8500_RTC, ab8500_rtc_time_regs[i], buf[i]); if (retval < 0) return retval; } /* Request a data write */ return abx500_set_register_interruptible(dev, AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST); } static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) { int retval, i; u8 rtc_ctrl, value; unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; unsigned long secs, mins; /* Check if the alarm is enabled or not */ retval = abx500_get_register_interruptible(dev, AB8500_RTC, AB8500_RTC_STAT_REG, &rtc_ctrl); if (retval < 0) return retval; 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 = abx500_get_register_interruptible(dev, AB8500_RTC, ab8500_rtc_alarm_regs[i], &value); if (retval < 0) return retval; buf[i] = value; } 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) { return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC, 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) { 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 = abx500_set_register_interruptible(dev, AB8500_RTC, ab8500_rtc_alarm_regs[i], buf[i]); if (retval < 0) return retval; } return ab8500_rtc_irq_enable(dev, alarm->enabled); } static int ab8500_rtc_set_calibration(struct device *dev, int calibration) { int retval; u8 rtccal = 0; /* * Check that the calibration value (which is in units of 0.5 * parts-per-million) is in the AB8500's range for RtcCalibration * register. -128 (0x80) is not permitted because the AB8500 uses * a sign-bit rather than two's complement, so 0x80 is just another * representation of zero. */ if ((calibration < -127) || (calibration > 127)) { dev_err(dev, "RtcCalibration value outside permitted range\n"); return -EINVAL; } /* * The AB8500 uses sign (in bit7) and magnitude (in bits0-7) * so need to convert to this sort of representation before writing * into RtcCalibration register... */ if (calibration >= 0) rtccal = 0x7F & calibration; else rtccal = ~(calibration - 1) | 0x80; retval = abx500_set_register_interruptible(dev, AB8500_RTC, AB8500_RTC_CALIB_REG, rtccal); return retval; } static int ab8500_rtc_get_calibration(struct device *dev, int *calibration) { int retval; u8 rtccal = 0; retval = abx500_get_register_interruptible(dev, AB8500_RTC, AB8500_RTC_CALIB_REG, &rtccal); if (retval >= 0) { /* * The AB8500 uses sign (in bit7) and magnitude (in bits0-7) * so need to convert value from RtcCalibration register into * a two's complement signed value... */ if (rtccal & 0x80) *calibration = 0 - (rtccal & 0x7F); else *calibration = 0x7F & rtccal; } return retval; } static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int retval; int calibration = 0; if (sscanf(buf, " %i ", &calibration) != 1) { dev_err(dev, "Failed to store RTC calibration attribute\n"); return -EINVAL; } retval = ab8500_rtc_set_calibration(dev, calibration); return retval ? retval : count; } static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev, struct device_attribute *attr, char *buf) { int retval = 0; int calibration = 0; retval = ab8500_rtc_get_calibration(dev, &calibration); if (retval < 0) { dev_err(dev, "Failed to read RTC calibration attribute\n"); sprintf(buf, "0\n"); return retval; } return sprintf(buf, "%d\n", calibration); } static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR, ab8500_sysfs_show_rtc_calibration, ab8500_sysfs_store_rtc_calibration); static int ab8500_sysfs_rtc_register(struct device *dev) { return device_create_file(dev, &dev_attr_rtc_calibration); } static void ab8500_sysfs_rtc_unregister(struct device *dev) { device_remove_file(dev, &dev_attr_rtc_calibration); } 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) { int err; struct rtc_device *rtc; u8 rtc_ctrl; int irq; irq = platform_get_irq_byname(pdev, "ALARM"); if (irq < 0) return irq; /* For RTC supply test */ err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC, AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA); if (err < 0) return err; /* Wait for reset by the PorRtc */ usleep_range(1000, 5000); err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC, AB8500_RTC_STAT_REG, &rtc_ctrl); if (err < 0) return err; /* Check if the RTC Supply fails */ if (!(rtc_ctrl & RTC_STATUS_DATA)) { dev_err(&pdev->dev, "RTC supply failure\n"); return -ENODEV; } device_init_wakeup(&pdev->dev, true); 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, IRQF_NO_SUSPEND | IRQF_ONESHOT, "ab8500-rtc", rtc); if (err < 0) { rtc_device_unregister(rtc); return err; } platform_set_drvdata(pdev, rtc); err = ab8500_sysfs_rtc_register(&pdev->dev); if (err) { dev_err(&pdev->dev, "sysfs RTC failed to register\n"); return err; } 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"); ab8500_sysfs_rtc_unregister(&pdev->dev); free_irq(irq, rtc); rtc_device_unregister(rtc); platform_set_drvdata(pdev, NULL); return 0; } static const struct of_device_id ab8500_rtc_match[] = { { .compatible = "stericsson,ab8500-rtc", }, {} }; static struct platform_driver ab8500_rtc_driver = { .driver = { .name = "ab8500-rtc", .owner = THIS_MODULE, .of_match_table = ab8500_rtc_match, }, .probe = ab8500_rtc_probe, .remove = __devexit_p(ab8500_rtc_remove), }; module_platform_driver(ab8500_rtc_driver); MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>"); MODULE_DESCRIPTION("AB8500 RTC Driver"); MODULE_LICENSE("GPL v2");