| /* |
| * 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, time64_t secs) |
| { |
| u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2, |
| AB3100_TI3, AB3100_TI4, AB3100_TI5}; |
| unsigned char buf[6]; |
| u64 hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2; |
| int err = 0; |
| int i; |
| |
| buf[0] = (hw_counter) & 0xFF; |
| buf[1] = (hw_counter >> 8) & 0xFF; |
| buf[2] = (hw_counter >> 16) & 0xFF; |
| buf[3] = (hw_counter >> 24) & 0xFF; |
| buf[4] = (hw_counter >> 32) & 0xFF; |
| buf[5] = (hw_counter >> 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) |
| { |
| time64_t 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 hw_counter; |
| u8 buf[6]; |
| |
| /* Read out time registers */ |
| err = abx500_get_register_page_interruptible(dev, 0, |
| AB3100_TI0, |
| buf, 6); |
| if (err != 0) |
| return err; |
| |
| hw_counter = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) | |
| ((u64) buf[3] << 24) | ((u64) buf[2] << 16) | |
| ((u64) buf[1] << 8) | (u64) buf[0]; |
| time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2); |
| } |
| |
| rtc_time64_to_tm(time, tm); |
| |
| return rtc_valid_tm(tm); |
| } |
| |
| static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
| { |
| time64_t time; |
| u64 hw_counter; |
| 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; |
| hw_counter = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) | |
| ((u64) buf[1] << 24) | ((u64) buf[0] << 16); |
| time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2); |
| |
| rtc_time64_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]; |
| time64_t secs; |
| u64 hw_counter; |
| int err; |
| int i; |
| |
| secs = rtc_tm_to_time64(&alarm->time); |
| hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2; |
| buf[0] = (hw_counter >> 16) & 0xFF; |
| buf[1] = (hw_counter >> 24) & 0xFF; |
| buf[2] = (hw_counter >> 32) & 0xFF; |
| buf[3] = (hw_counter >> 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_mmss64 = 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 = devm_rtc_device_register(&pdev->dev, "ab3100-rtc", |
| &ab3100_rtc_ops, THIS_MODULE); |
| if (IS_ERR(rtc)) { |
| err = PTR_ERR(rtc); |
| return err; |
| } |
| platform_set_drvdata(pdev, rtc); |
| |
| return 0; |
| } |
| |
| static struct platform_driver ab3100_rtc_driver = { |
| .driver = { |
| .name = "ab3100-rtc", |
| }, |
| }; |
| |
| module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe); |
| |
| MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); |
| MODULE_DESCRIPTION("AB3100 RTC Driver"); |
| MODULE_LICENSE("GPL"); |