484 lines
12 KiB
C
484 lines
12 KiB
C
/*
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* Copyright (C) ST-Ericsson SA 2010
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*
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* License terms: GNU General Public License (GPL) version 2
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* Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
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*
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* RTC clock driver for the RTC part of the AB8500 Power management chip.
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* Based on RTC clock driver for the AB3100 Analog Baseband Chip by
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* Linus Walleij <linus.walleij@stericsson.com>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#include <linux/mfd/abx500.h>
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#include <linux/mfd/abx500/ab8500.h>
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#include <linux/delay.h>
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#include <linux/of.h>
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#include <linux/pm_wakeirq.h>
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#define AB8500_RTC_SOFF_STAT_REG 0x00
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#define AB8500_RTC_CC_CONF_REG 0x01
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#define AB8500_RTC_READ_REQ_REG 0x02
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#define AB8500_RTC_WATCH_TSECMID_REG 0x03
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#define AB8500_RTC_WATCH_TSECHI_REG 0x04
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#define AB8500_RTC_WATCH_TMIN_LOW_REG 0x05
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#define AB8500_RTC_WATCH_TMIN_MID_REG 0x06
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#define AB8500_RTC_WATCH_TMIN_HI_REG 0x07
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#define AB8500_RTC_ALRM_MIN_LOW_REG 0x08
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#define AB8500_RTC_ALRM_MIN_MID_REG 0x09
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#define AB8500_RTC_ALRM_MIN_HI_REG 0x0A
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#define AB8500_RTC_STAT_REG 0x0B
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#define AB8500_RTC_BKUP_CHG_REG 0x0C
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#define AB8500_RTC_FORCE_BKUP_REG 0x0D
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#define AB8500_RTC_CALIB_REG 0x0E
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#define AB8500_RTC_SWITCH_STAT_REG 0x0F
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/* RtcReadRequest bits */
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#define RTC_READ_REQUEST 0x01
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#define RTC_WRITE_REQUEST 0x02
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/* RtcCtrl bits */
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#define RTC_ALARM_ENA 0x04
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#define RTC_STATUS_DATA 0x01
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#define COUNTS_PER_SEC (0xF000 / 60)
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#define AB8500_RTC_EPOCH 2000
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static const u8 ab8500_rtc_time_regs[] = {
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AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
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AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
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AB8500_RTC_WATCH_TSECMID_REG
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};
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static const u8 ab8500_rtc_alarm_regs[] = {
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AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
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AB8500_RTC_ALRM_MIN_LOW_REG
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};
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/* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */
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static unsigned long get_elapsed_seconds(int year)
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{
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unsigned long secs;
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struct rtc_time tm = {
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.tm_year = year - 1900,
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.tm_mday = 1,
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};
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/*
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* This function calculates secs from 1970 and not from
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* 1900, even if we supply the offset from year 1900.
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*/
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rtc_tm_to_time(&tm, &secs);
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return secs;
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}
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static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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unsigned long timeout = jiffies + HZ;
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int retval, i;
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unsigned long mins, secs;
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unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
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u8 value;
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/* Request a data read */
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retval = abx500_set_register_interruptible(dev,
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AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
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if (retval < 0)
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return retval;
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/* Wait for some cycles after enabling the rtc read in ab8500 */
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while (time_before(jiffies, timeout)) {
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retval = abx500_get_register_interruptible(dev,
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AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
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if (retval < 0)
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return retval;
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if (!(value & RTC_READ_REQUEST))
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break;
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usleep_range(1000, 5000);
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}
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/* Read the Watchtime registers */
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for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
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retval = abx500_get_register_interruptible(dev,
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AB8500_RTC, ab8500_rtc_time_regs[i], &value);
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if (retval < 0)
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return retval;
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buf[i] = value;
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}
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mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
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secs = (buf[3] << 8) | buf[4];
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secs = secs / COUNTS_PER_SEC;
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secs = secs + (mins * 60);
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/* Add back the initially subtracted number of seconds */
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secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
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rtc_time_to_tm(secs, tm);
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return 0;
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}
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static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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int retval, i;
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unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
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unsigned long no_secs, no_mins, secs = 0;
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if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) {
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dev_dbg(dev, "year should be equal to or greater than %d\n",
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AB8500_RTC_EPOCH);
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return -EINVAL;
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}
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/* Get the number of seconds since 1970 */
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rtc_tm_to_time(tm, &secs);
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/*
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* Convert it to the number of seconds since 01-01-2000 00:00:00, since
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* we only have a small counter in the RTC.
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*/
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secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
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no_mins = secs / 60;
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no_secs = secs % 60;
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/* Make the seconds count as per the RTC resolution */
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no_secs = no_secs * COUNTS_PER_SEC;
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buf[4] = no_secs & 0xFF;
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buf[3] = (no_secs >> 8) & 0xFF;
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buf[2] = no_mins & 0xFF;
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buf[1] = (no_mins >> 8) & 0xFF;
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buf[0] = (no_mins >> 16) & 0xFF;
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for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
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retval = abx500_set_register_interruptible(dev, AB8500_RTC,
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ab8500_rtc_time_regs[i], buf[i]);
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if (retval < 0)
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return retval;
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}
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/* Request a data write */
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return abx500_set_register_interruptible(dev, AB8500_RTC,
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AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
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}
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static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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int retval, i;
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u8 rtc_ctrl, value;
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unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
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unsigned long secs, mins;
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/* Check if the alarm is enabled or not */
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retval = abx500_get_register_interruptible(dev, AB8500_RTC,
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AB8500_RTC_STAT_REG, &rtc_ctrl);
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if (retval < 0)
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return retval;
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if (rtc_ctrl & RTC_ALARM_ENA)
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alarm->enabled = 1;
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else
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alarm->enabled = 0;
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alarm->pending = 0;
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for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
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retval = abx500_get_register_interruptible(dev, AB8500_RTC,
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ab8500_rtc_alarm_regs[i], &value);
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if (retval < 0)
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return retval;
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buf[i] = value;
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}
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mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
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secs = mins * 60;
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/* Add back the initially subtracted number of seconds */
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secs += get_elapsed_seconds(AB8500_RTC_EPOCH);
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rtc_time_to_tm(secs, &alarm->time);
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return rtc_valid_tm(&alarm->time);
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}
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static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
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{
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return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
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AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
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enabled ? RTC_ALARM_ENA : 0);
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}
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static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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int retval, i;
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unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
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unsigned long mins, secs = 0, cursec = 0;
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struct rtc_time curtm;
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if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) {
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dev_dbg(dev, "year should be equal to or greater than %d\n",
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AB8500_RTC_EPOCH);
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return -EINVAL;
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}
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/* Get the number of seconds since 1970 */
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rtc_tm_to_time(&alarm->time, &secs);
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/*
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* Check whether alarm is set less than 1min.
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* Since our RTC doesn't support alarm resolution less than 1min,
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* return -EINVAL, so UIE EMUL can take it up, incase of UIE_ON
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*/
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ab8500_rtc_read_time(dev, &curtm); /* Read current time */
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rtc_tm_to_time(&curtm, &cursec);
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if ((secs - cursec) < 59) {
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dev_dbg(dev, "Alarm less than 1 minute not supported\r\n");
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return -EINVAL;
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}
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/*
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* Convert it to the number of seconds since 01-01-2000 00:00:00, since
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* we only have a small counter in the RTC.
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*/
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secs -= get_elapsed_seconds(AB8500_RTC_EPOCH);
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mins = secs / 60;
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buf[2] = mins & 0xFF;
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buf[1] = (mins >> 8) & 0xFF;
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buf[0] = (mins >> 16) & 0xFF;
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/* Set the alarm time */
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for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
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retval = abx500_set_register_interruptible(dev, AB8500_RTC,
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ab8500_rtc_alarm_regs[i], buf[i]);
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if (retval < 0)
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return retval;
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}
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return ab8500_rtc_irq_enable(dev, alarm->enabled);
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}
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static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
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{
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int retval;
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u8 rtccal = 0;
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/*
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* Check that the calibration value (which is in units of 0.5
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* parts-per-million) is in the AB8500's range for RtcCalibration
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* register. -128 (0x80) is not permitted because the AB8500 uses
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* a sign-bit rather than two's complement, so 0x80 is just another
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* representation of zero.
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*/
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if ((calibration < -127) || (calibration > 127)) {
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dev_err(dev, "RtcCalibration value outside permitted range\n");
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return -EINVAL;
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}
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/*
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* The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
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* so need to convert to this sort of representation before writing
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* into RtcCalibration register...
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*/
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if (calibration >= 0)
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rtccal = 0x7F & calibration;
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else
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rtccal = ~(calibration - 1) | 0x80;
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retval = abx500_set_register_interruptible(dev, AB8500_RTC,
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AB8500_RTC_CALIB_REG, rtccal);
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return retval;
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}
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static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
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{
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int retval;
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u8 rtccal = 0;
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retval = abx500_get_register_interruptible(dev, AB8500_RTC,
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AB8500_RTC_CALIB_REG, &rtccal);
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if (retval >= 0) {
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/*
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* The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
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* so need to convert value from RtcCalibration register into
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* a two's complement signed value...
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*/
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if (rtccal & 0x80)
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*calibration = 0 - (rtccal & 0x7F);
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else
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*calibration = 0x7F & rtccal;
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}
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return retval;
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}
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static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int retval;
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int calibration = 0;
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if (sscanf(buf, " %i ", &calibration) != 1) {
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dev_err(dev, "Failed to store RTC calibration attribute\n");
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return -EINVAL;
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}
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retval = ab8500_rtc_set_calibration(dev, calibration);
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return retval ? retval : count;
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}
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static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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int retval = 0;
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int calibration = 0;
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retval = ab8500_rtc_get_calibration(dev, &calibration);
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if (retval < 0) {
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dev_err(dev, "Failed to read RTC calibration attribute\n");
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sprintf(buf, "0\n");
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return retval;
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}
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return sprintf(buf, "%d\n", calibration);
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}
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static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
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ab8500_sysfs_show_rtc_calibration,
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ab8500_sysfs_store_rtc_calibration);
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static int ab8500_sysfs_rtc_register(struct device *dev)
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{
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return device_create_file(dev, &dev_attr_rtc_calibration);
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}
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static void ab8500_sysfs_rtc_unregister(struct device *dev)
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{
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device_remove_file(dev, &dev_attr_rtc_calibration);
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}
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static irqreturn_t rtc_alarm_handler(int irq, void *data)
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{
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struct rtc_device *rtc = data;
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unsigned long events = RTC_IRQF | RTC_AF;
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dev_dbg(&rtc->dev, "%s\n", __func__);
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rtc_update_irq(rtc, 1, events);
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return IRQ_HANDLED;
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}
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static const struct rtc_class_ops ab8500_rtc_ops = {
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.read_time = ab8500_rtc_read_time,
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.set_time = ab8500_rtc_set_time,
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.read_alarm = ab8500_rtc_read_alarm,
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.set_alarm = ab8500_rtc_set_alarm,
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.alarm_irq_enable = ab8500_rtc_irq_enable,
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};
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static const struct platform_device_id ab85xx_rtc_ids[] = {
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{ "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
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static int ab8500_rtc_probe(struct platform_device *pdev)
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{
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const struct platform_device_id *platid = platform_get_device_id(pdev);
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int err;
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struct rtc_device *rtc;
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u8 rtc_ctrl;
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int irq;
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irq = platform_get_irq_byname(pdev, "ALARM");
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if (irq < 0)
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return irq;
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/* For RTC supply test */
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err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
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AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
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if (err < 0)
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return err;
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/* Wait for reset by the PorRtc */
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usleep_range(1000, 5000);
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err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
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AB8500_RTC_STAT_REG, &rtc_ctrl);
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if (err < 0)
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return err;
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/* Check if the RTC Supply fails */
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if (!(rtc_ctrl & RTC_STATUS_DATA)) {
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dev_err(&pdev->dev, "RTC supply failure\n");
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return -ENODEV;
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}
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device_init_wakeup(&pdev->dev, true);
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rtc = devm_rtc_device_register(&pdev->dev, "ab8500-rtc",
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(struct rtc_class_ops *)platid->driver_data,
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THIS_MODULE);
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if (IS_ERR(rtc)) {
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dev_err(&pdev->dev, "Registration failed\n");
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err = PTR_ERR(rtc);
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return err;
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}
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err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
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rtc_alarm_handler, IRQF_ONESHOT,
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"ab8500-rtc", rtc);
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if (err < 0)
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return err;
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dev_pm_set_wake_irq(&pdev->dev, irq);
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platform_set_drvdata(pdev, rtc);
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err = ab8500_sysfs_rtc_register(&pdev->dev);
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if (err) {
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dev_err(&pdev->dev, "sysfs RTC failed to register\n");
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return err;
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}
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rtc->uie_unsupported = 1;
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return 0;
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}
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static int ab8500_rtc_remove(struct platform_device *pdev)
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{
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dev_pm_clear_wake_irq(&pdev->dev);
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device_init_wakeup(&pdev->dev, false);
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ab8500_sysfs_rtc_unregister(&pdev->dev);
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return 0;
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}
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static struct platform_driver ab8500_rtc_driver = {
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.driver = {
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.name = "ab8500-rtc",
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},
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.probe = ab8500_rtc_probe,
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.remove = ab8500_rtc_remove,
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.id_table = ab85xx_rtc_ids,
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};
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module_platform_driver(ab8500_rtc_driver);
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MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
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MODULE_DESCRIPTION("AB8500 RTC Driver");
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MODULE_LICENSE("GPL v2");
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