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254 lines
6.5 KiB
254 lines
6.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2007-2009 ST-Ericsson AB |
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* RTC clock driver for the AB3100 Analog Baseband Chip |
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* Author: Linus Walleij <[email protected]> |
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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_time(struct device *dev, struct rtc_time *tm) |
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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 = rtc_tm_to_time64(tm) * 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_time = ab3100_rtc_set_time, |
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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_allocate_device(&pdev->dev); |
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if (IS_ERR(rtc)) |
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return PTR_ERR(rtc); |
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rtc->ops = &ab3100_rtc_ops; |
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/* 48bit counter at (AB3100_RTC_CLOCK_RATE * 2) */ |
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rtc->range_max = U32_MAX; |
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platform_set_drvdata(pdev, rtc); |
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return rtc_register_device(rtc); |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("AB3100 RTC Driver"); |
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MODULE_LICENSE("GPL");
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