/* * Copyright (C) 2007-2009 ST-Ericsson AB * License terms: GNU General Public License (GPL) version 2 * RTC clock driver for the AB3100 Analog Baseband Chip * Author: 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> /* Clock rate in Hz */ #define AB3100_RTC_CLOCK_RATE 32768 /* * The AB3100 RTC registers. These are the same for * AB3000 and AB3100. * Control register: * Bit 0: RTC Monitor cleared=0, active=1, if you set it * to 1 it remains active until RTC power is lost. * Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass * Bit 2: Alarm on, 0 = off, 1 = on * Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled */ #define AB3100_RTC 0x53 /* default setting, buffer disabled, alarm on */ #define RTC_SETTING 0x30 /* Alarm when AL0-AL3 == TI0-TI3 */ #define AB3100_AL0 0x56 #define AB3100_AL1 0x57 #define AB3100_AL2 0x58 #define AB3100_AL3 0x59 /* This 48-bit register that counts up at 32768 Hz */ #define AB3100_TI0 0x5a #define AB3100_TI1 0x5b #define AB3100_TI2 0x5c #define AB3100_TI3 0x5d #define AB3100_TI4 0x5e #define AB3100_TI5 0x5f /* * RTC clock functions and device struct declaration */ static int ab3100_rtc_set_mmss(struct device *dev, unsigned long secs) { u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2, AB3100_TI3, AB3100_TI4, AB3100_TI5}; unsigned char buf[6]; u64 fat_time = (u64) secs * AB3100_RTC_CLOCK_RATE * 2; int err = 0; int i; buf[0] = (fat_time) & 0xFF; buf[1] = (fat_time >> 8) & 0xFF; buf[2] = (fat_time >> 16) & 0xFF; buf[3] = (fat_time >> 24) & 0xFF; buf[4] = (fat_time >> 32) & 0xFF; buf[5] = (fat_time >> 40) & 0xFF; for (i = 0; i < 6; i++) { err = abx500_set_register_interruptible(dev, 0, regs[i], buf[i]); if (err) return err; } /* Set the flag to mark that the clock is now set */ return abx500_mask_and_set_register_interruptible(dev, 0, AB3100_RTC, 0x01, 0x01); } static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm) { unsigned long time; u8 rtcval; int err; err = abx500_get_register_interruptible(dev, 0, AB3100_RTC, &rtcval); if (err) return err; if (!(rtcval & 0x01)) { dev_info(dev, "clock not set (lost power)"); return -EINVAL; } else { u64 fat_time; u8 buf[6]; /* Read out time registers */ err = abx500_get_register_page_interruptible(dev, 0, AB3100_TI0, buf, 6); if (err != 0) return err; fat_time = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) | ((u64) buf[3] << 24) | ((u64) buf[2] << 16) | ((u64) buf[1] << 8) | (u64) buf[0]; time = (unsigned long) (fat_time / (u64) (AB3100_RTC_CLOCK_RATE * 2)); } rtc_time_to_tm(time, tm); return rtc_valid_tm(tm); } static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) { unsigned long time; u64 fat_time; u8 buf[6]; u8 rtcval; int err; /* Figure out if alarm is enabled or not */ err = abx500_get_register_interruptible(dev, 0, AB3100_RTC, &rtcval); if (err) return err; if (rtcval & 0x04) alarm->enabled = 1; else alarm->enabled = 0; /* No idea how this could be represented */ alarm->pending = 0; /* Read out alarm registers, only 4 bytes */ err = abx500_get_register_page_interruptible(dev, 0, AB3100_AL0, buf, 4); if (err) return err; fat_time = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) | ((u64) buf[1] << 24) | ((u64) buf[0] << 16); time = (unsigned long) (fat_time / (u64) (AB3100_RTC_CLOCK_RATE * 2)); rtc_time_to_tm(time, &alarm->time); return rtc_valid_tm(&alarm->time); } static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) { u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3}; unsigned char buf[4]; unsigned long secs; u64 fat_time; int err; int i; rtc_tm_to_time(&alarm->time, &secs); fat_time = (u64) secs * AB3100_RTC_CLOCK_RATE * 2; buf[0] = (fat_time >> 16) & 0xFF; buf[1] = (fat_time >> 24) & 0xFF; buf[2] = (fat_time >> 32) & 0xFF; buf[3] = (fat_time >> 40) & 0xFF; /* Set the alarm */ for (i = 0; i < 4; i++) { err = abx500_set_register_interruptible(dev, 0, regs[i], buf[i]); if (err) return err; } /* Then enable the alarm */ return abx500_mask_and_set_register_interruptible(dev, 0, AB3100_RTC, (1 << 2), alarm->enabled << 2); } static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled) { /* * It's not possible to enable/disable the alarm IRQ for this RTC. * It does not actually trigger any IRQ: instead its only function is * to power up the system, if it wasn't on. This will manifest as * a "power up cause" in the AB3100 power driver (battery charging etc) * and need to be handled there instead. */ if (enabled) return abx500_mask_and_set_register_interruptible(dev, 0, AB3100_RTC, (1 << 2), 1 << 2); else return abx500_mask_and_set_register_interruptible(dev, 0, AB3100_RTC, (1 << 2), 0); } static const struct rtc_class_ops ab3100_rtc_ops = { .read_time = ab3100_rtc_read_time, .set_mmss = ab3100_rtc_set_mmss, .read_alarm = ab3100_rtc_read_alarm, .set_alarm = ab3100_rtc_set_alarm, .alarm_irq_enable = ab3100_rtc_irq_enable, }; static int __init ab3100_rtc_probe(struct platform_device *pdev) { int err; u8 regval; struct rtc_device *rtc; /* The first RTC register needs special treatment */ err = abx500_get_register_interruptible(&pdev->dev, 0, AB3100_RTC, ®val); if (err) { dev_err(&pdev->dev, "unable to read RTC register\n"); return -ENODEV; } if ((regval & 0xFE) != RTC_SETTING) { dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n", regval); } if ((regval & 1) == 0) { /* * Set bit to detect power loss. * This bit remains until RTC power is lost. */ regval = 1 | RTC_SETTING; err = abx500_set_register_interruptible(&pdev->dev, 0, AB3100_RTC, regval); /* Ignore any error on this write */ } rtc = rtc_device_register("ab3100-rtc", &pdev->dev, &ab3100_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) { err = PTR_ERR(rtc); return err; } return 0; } static int __exit ab3100_rtc_remove(struct platform_device *pdev) { struct rtc_device *rtc = platform_get_drvdata(pdev); rtc_device_unregister(rtc); return 0; } static struct platform_driver ab3100_rtc_driver = { .driver = { .name = "ab3100-rtc", .owner = THIS_MODULE, }, .remove = __exit_p(ab3100_rtc_remove), }; static int __init ab3100_rtc_init(void) { return platform_driver_probe(&ab3100_rtc_driver, ab3100_rtc_probe); } static void __exit ab3100_rtc_exit(void) { platform_driver_unregister(&ab3100_rtc_driver); } module_init(ab3100_rtc_init); module_exit(ab3100_rtc_exit); MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); MODULE_DESCRIPTION("AB3100 RTC Driver"); MODULE_LICENSE("GPL");