mirror of https://gitee.com/openkylin/linux.git
253 lines
6.4 KiB
C
253 lines
6.4 KiB
C
/*
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* Copyright (C) 2007-2009 ST-Ericsson AB
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* License terms: GNU General Public License (GPL) version 2
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* RTC clock driver for the AB3100 Analog Baseband Chip
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* Author: 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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/* Clock rate in Hz */
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#define AB3100_RTC_CLOCK_RATE 32768
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/*
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* The AB3100 RTC registers. These are the same for
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* AB3000 and AB3100.
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* Control register:
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* Bit 0: RTC Monitor cleared=0, active=1, if you set it
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* to 1 it remains active until RTC power is lost.
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* Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass
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* Bit 2: Alarm on, 0 = off, 1 = on
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* Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled
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*/
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#define AB3100_RTC 0x53
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/* default setting, buffer disabled, alarm on */
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#define RTC_SETTING 0x30
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/* Alarm when AL0-AL3 == TI0-TI3 */
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#define AB3100_AL0 0x56
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#define AB3100_AL1 0x57
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#define AB3100_AL2 0x58
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#define AB3100_AL3 0x59
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/* This 48-bit register that counts up at 32768 Hz */
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#define AB3100_TI0 0x5a
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#define AB3100_TI1 0x5b
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#define AB3100_TI2 0x5c
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#define AB3100_TI3 0x5d
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#define AB3100_TI4 0x5e
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#define AB3100_TI5 0x5f
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/*
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* RTC clock functions and device struct declaration
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*/
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static int ab3100_rtc_set_mmss(struct device *dev, time64_t secs)
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{
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u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2,
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AB3100_TI3, AB3100_TI4, AB3100_TI5};
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unsigned char buf[6];
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u64 hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;
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int err = 0;
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int i;
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buf[0] = (hw_counter) & 0xFF;
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buf[1] = (hw_counter >> 8) & 0xFF;
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buf[2] = (hw_counter >> 16) & 0xFF;
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buf[3] = (hw_counter >> 24) & 0xFF;
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buf[4] = (hw_counter >> 32) & 0xFF;
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buf[5] = (hw_counter >> 40) & 0xFF;
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for (i = 0; i < 6; i++) {
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err = abx500_set_register_interruptible(dev, 0,
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regs[i], buf[i]);
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if (err)
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return err;
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}
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/* Set the flag to mark that the clock is now set */
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return abx500_mask_and_set_register_interruptible(dev, 0,
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AB3100_RTC,
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0x01, 0x01);
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}
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static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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time64_t time;
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u8 rtcval;
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int err;
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err = abx500_get_register_interruptible(dev, 0,
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AB3100_RTC, &rtcval);
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if (err)
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return err;
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if (!(rtcval & 0x01)) {
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dev_info(dev, "clock not set (lost power)");
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return -EINVAL;
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} else {
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u64 hw_counter;
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u8 buf[6];
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/* Read out time registers */
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err = abx500_get_register_page_interruptible(dev, 0,
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AB3100_TI0,
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buf, 6);
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if (err != 0)
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return err;
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hw_counter = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) |
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((u64) buf[3] << 24) | ((u64) buf[2] << 16) |
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((u64) buf[1] << 8) | (u64) buf[0];
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time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);
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}
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rtc_time64_to_tm(time, tm);
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return 0;
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}
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static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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time64_t time;
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u64 hw_counter;
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u8 buf[6];
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u8 rtcval;
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int err;
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/* Figure out if alarm is enabled or not */
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err = abx500_get_register_interruptible(dev, 0,
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AB3100_RTC, &rtcval);
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if (err)
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return err;
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if (rtcval & 0x04)
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alarm->enabled = 1;
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else
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alarm->enabled = 0;
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/* No idea how this could be represented */
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alarm->pending = 0;
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/* Read out alarm registers, only 4 bytes */
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err = abx500_get_register_page_interruptible(dev, 0,
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AB3100_AL0, buf, 4);
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if (err)
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return err;
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hw_counter = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) |
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((u64) buf[1] << 24) | ((u64) buf[0] << 16);
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time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2);
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rtc_time64_to_tm(time, &alarm->time);
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return rtc_valid_tm(&alarm->time);
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}
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static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3};
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unsigned char buf[4];
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time64_t secs;
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u64 hw_counter;
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int err;
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int i;
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secs = rtc_tm_to_time64(&alarm->time);
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hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2;
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buf[0] = (hw_counter >> 16) & 0xFF;
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buf[1] = (hw_counter >> 24) & 0xFF;
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buf[2] = (hw_counter >> 32) & 0xFF;
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buf[3] = (hw_counter >> 40) & 0xFF;
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/* Set the alarm */
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for (i = 0; i < 4; i++) {
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err = abx500_set_register_interruptible(dev, 0,
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regs[i], buf[i]);
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if (err)
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return err;
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}
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/* Then enable the alarm */
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return abx500_mask_and_set_register_interruptible(dev, 0,
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AB3100_RTC, (1 << 2),
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alarm->enabled << 2);
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}
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static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled)
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{
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/*
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* It's not possible to enable/disable the alarm IRQ for this RTC.
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* It does not actually trigger any IRQ: instead its only function is
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* to power up the system, if it wasn't on. This will manifest as
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* a "power up cause" in the AB3100 power driver (battery charging etc)
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* and need to be handled there instead.
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*/
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if (enabled)
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return abx500_mask_and_set_register_interruptible(dev, 0,
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AB3100_RTC, (1 << 2),
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1 << 2);
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else
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return abx500_mask_and_set_register_interruptible(dev, 0,
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AB3100_RTC, (1 << 2),
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0);
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}
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static const struct rtc_class_ops ab3100_rtc_ops = {
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.read_time = ab3100_rtc_read_time,
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.set_mmss64 = ab3100_rtc_set_mmss,
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.read_alarm = ab3100_rtc_read_alarm,
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.set_alarm = ab3100_rtc_set_alarm,
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.alarm_irq_enable = ab3100_rtc_irq_enable,
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};
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static int __init ab3100_rtc_probe(struct platform_device *pdev)
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{
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int err;
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u8 regval;
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struct rtc_device *rtc;
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/* The first RTC register needs special treatment */
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err = abx500_get_register_interruptible(&pdev->dev, 0,
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AB3100_RTC, ®val);
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if (err) {
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dev_err(&pdev->dev, "unable to read RTC register\n");
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return -ENODEV;
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}
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if ((regval & 0xFE) != RTC_SETTING) {
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dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n",
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regval);
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}
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if ((regval & 1) == 0) {
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/*
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* Set bit to detect power loss.
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* This bit remains until RTC power is lost.
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*/
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regval = 1 | RTC_SETTING;
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err = abx500_set_register_interruptible(&pdev->dev, 0,
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AB3100_RTC, regval);
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/* Ignore any error on this write */
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}
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rtc = devm_rtc_device_register(&pdev->dev, "ab3100-rtc",
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&ab3100_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc)) {
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err = PTR_ERR(rtc);
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return err;
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}
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platform_set_drvdata(pdev, rtc);
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return 0;
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}
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static struct platform_driver ab3100_rtc_driver = {
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.driver = {
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.name = "ab3100-rtc",
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},
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};
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module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe);
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MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
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MODULE_DESCRIPTION("AB3100 RTC Driver");
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MODULE_LICENSE("GPL");
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