diff options
Diffstat (limited to 'drivers/rtc/rtc-ab8500.c')
| -rw-r--r-- | drivers/rtc/rtc-ab8500.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ab8500.c b/drivers/rtc/rtc-ab8500.c new file mode 100644 index 000000000..75bb2ac90 --- /dev/null +++ b/drivers/rtc/rtc-ab8500.c @@ -0,0 +1,414 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) ST-Ericsson SA 2010 + * + * 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> +#include <linux/pm_wakeirq.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) + +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 +}; + +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; + + /* 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); + + rtc_time64_to_tm(secs, tm); + return 0; +} + +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; + + secs = rtc_tm_to_time64(tm); + + 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; + + rtc_time64_to_tm(secs, &alarm->time); + + return 0; +} + +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; + + mins = (unsigned long)rtc_tm_to_time64(&alarm->time) / 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 struct attribute *ab8500_rtc_attrs[] = { + &dev_attr_rtc_calibration.attr, + NULL +}; + +static const struct attribute_group ab8500_rtc_sysfs_files = { + .attrs = ab8500_rtc_attrs, +}; + +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 const struct platform_device_id ab85xx_rtc_ids[] = { + { "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids); + +static int ab8500_rtc_probe(struct platform_device *pdev) +{ + const struct platform_device_id *platid = platform_get_device_id(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 = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + rtc->ops = (struct rtc_class_ops *)platid->driver_data; + + err = devm_request_threaded_irq(&pdev->dev, irq, NULL, + rtc_alarm_handler, IRQF_ONESHOT, + "ab8500-rtc", rtc); + if (err < 0) + return err; + + dev_pm_set_wake_irq(&pdev->dev, irq); + platform_set_drvdata(pdev, rtc); + + set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features); + clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features); + + rtc->range_max = (1ULL << 24) * 60 - 1; // 24-bit minutes + 59 secs + rtc->start_secs = RTC_TIMESTAMP_BEGIN_2000; + rtc->set_start_time = true; + + err = rtc_add_group(rtc, &ab8500_rtc_sysfs_files); + if (err) + return err; + + return devm_rtc_register_device(rtc); +} + +static void ab8500_rtc_remove(struct platform_device *pdev) +{ + dev_pm_clear_wake_irq(&pdev->dev); + device_init_wakeup(&pdev->dev, false); +} + +static struct platform_driver ab8500_rtc_driver = { + .driver = { + .name = "ab8500-rtc", + }, + .probe = ab8500_rtc_probe, + .remove_new = ab8500_rtc_remove, + .id_table = ab85xx_rtc_ids, +}; + +module_platform_driver(ab8500_rtc_driver); + +MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>"); +MODULE_DESCRIPTION("AB8500 RTC Driver"); +MODULE_LICENSE("GPL v2"); |