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224 lines
5.2 KiB
224 lines
5.2 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Real Time Clock driver for Conexant Digicolor |
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* |
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* Copyright (C) 2015 Paradox Innovation Ltd. |
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* |
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* Author: Baruch Siach <[email protected]> |
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*/ |
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#include <linux/io.h> |
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#include <linux/iopoll.h> |
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#include <linux/delay.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/rtc.h> |
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#include <linux/of.h> |
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#define DC_RTC_CONTROL 0x0 |
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#define DC_RTC_TIME 0x8 |
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#define DC_RTC_REFERENCE 0xc |
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#define DC_RTC_ALARM 0x10 |
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#define DC_RTC_INTFLAG_CLEAR 0x14 |
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#define DC_RTC_INTENABLE 0x16 |
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#define DC_RTC_CMD_MASK 0xf |
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#define DC_RTC_GO_BUSY BIT(7) |
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#define CMD_NOP 0 |
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#define CMD_RESET 1 |
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#define CMD_WRITE 3 |
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#define CMD_READ 4 |
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#define CMD_DELAY_US (10*1000) |
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#define CMD_TIMEOUT_US (500*CMD_DELAY_US) |
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struct dc_rtc { |
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struct rtc_device *rtc_dev; |
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void __iomem *regs; |
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}; |
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static int dc_rtc_cmds(struct dc_rtc *rtc, const u8 *cmds, int len) |
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{ |
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u8 val; |
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int i, ret; |
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for (i = 0; i < len; i++) { |
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writeb_relaxed((cmds[i] & DC_RTC_CMD_MASK) | DC_RTC_GO_BUSY, |
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rtc->regs + DC_RTC_CONTROL); |
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ret = readb_relaxed_poll_timeout( |
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rtc->regs + DC_RTC_CONTROL, val, |
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!(val & DC_RTC_GO_BUSY), CMD_DELAY_US, CMD_TIMEOUT_US); |
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if (ret < 0) |
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return ret; |
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} |
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return 0; |
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} |
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static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val) |
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{ |
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static const u8 read_cmds[] = {CMD_READ, CMD_NOP}; |
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u32 reference, time1, time2; |
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int ret; |
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ret = dc_rtc_cmds(rtc, read_cmds, ARRAY_SIZE(read_cmds)); |
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if (ret < 0) |
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return ret; |
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reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE); |
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time1 = readl_relaxed(rtc->regs + DC_RTC_TIME); |
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/* Read twice to ensure consistency */ |
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while (1) { |
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time2 = readl_relaxed(rtc->regs + DC_RTC_TIME); |
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if (time1 == time2) |
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break; |
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time1 = time2; |
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} |
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*val = reference + time1; |
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return 0; |
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} |
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static int dc_rtc_write(struct dc_rtc *rtc, u32 val) |
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{ |
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static const u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP}; |
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writel_relaxed(val, rtc->regs + DC_RTC_REFERENCE); |
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return dc_rtc_cmds(rtc, write_cmds, ARRAY_SIZE(write_cmds)); |
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} |
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static int dc_rtc_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct dc_rtc *rtc = dev_get_drvdata(dev); |
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unsigned long now; |
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int ret; |
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ret = dc_rtc_read(rtc, &now); |
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if (ret < 0) |
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return ret; |
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rtc_time64_to_tm(now, tm); |
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return 0; |
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} |
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static int dc_rtc_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct dc_rtc *rtc = dev_get_drvdata(dev); |
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return dc_rtc_write(rtc, rtc_tm_to_time64(tm)); |
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} |
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static int dc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
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{ |
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struct dc_rtc *rtc = dev_get_drvdata(dev); |
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u32 alarm_reg, reference; |
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unsigned long now; |
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int ret; |
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alarm_reg = readl_relaxed(rtc->regs + DC_RTC_ALARM); |
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reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE); |
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rtc_time64_to_tm(reference + alarm_reg, &alarm->time); |
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ret = dc_rtc_read(rtc, &now); |
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if (ret < 0) |
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return ret; |
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alarm->pending = alarm_reg + reference > now; |
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alarm->enabled = readl_relaxed(rtc->regs + DC_RTC_INTENABLE); |
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return 0; |
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} |
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static int dc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) |
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{ |
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struct dc_rtc *rtc = dev_get_drvdata(dev); |
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time64_t alarm_time; |
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u32 reference; |
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alarm_time = rtc_tm_to_time64(&alarm->time); |
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reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE); |
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writel_relaxed(alarm_time - reference, rtc->regs + DC_RTC_ALARM); |
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writeb_relaxed(!!alarm->enabled, rtc->regs + DC_RTC_INTENABLE); |
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return 0; |
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} |
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static int dc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) |
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{ |
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struct dc_rtc *rtc = dev_get_drvdata(dev); |
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writeb_relaxed(!!enabled, rtc->regs + DC_RTC_INTENABLE); |
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return 0; |
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} |
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static const struct rtc_class_ops dc_rtc_ops = { |
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.read_time = dc_rtc_read_time, |
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.set_time = dc_rtc_set_time, |
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.read_alarm = dc_rtc_read_alarm, |
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.set_alarm = dc_rtc_set_alarm, |
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.alarm_irq_enable = dc_rtc_alarm_irq_enable, |
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}; |
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static irqreturn_t dc_rtc_irq(int irq, void *dev_id) |
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{ |
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struct dc_rtc *rtc = dev_id; |
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writeb_relaxed(1, rtc->regs + DC_RTC_INTFLAG_CLEAR); |
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rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF); |
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return IRQ_HANDLED; |
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} |
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static int __init dc_rtc_probe(struct platform_device *pdev) |
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{ |
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struct dc_rtc *rtc; |
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int irq, ret; |
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rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); |
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if (!rtc) |
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return -ENOMEM; |
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rtc->regs = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(rtc->regs)) |
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return PTR_ERR(rtc->regs); |
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rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); |
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if (IS_ERR(rtc->rtc_dev)) |
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return PTR_ERR(rtc->rtc_dev); |
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irq = platform_get_irq(pdev, 0); |
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if (irq < 0) |
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return irq; |
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ret = devm_request_irq(&pdev->dev, irq, dc_rtc_irq, 0, pdev->name, rtc); |
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if (ret < 0) |
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return ret; |
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platform_set_drvdata(pdev, rtc); |
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rtc->rtc_dev->ops = &dc_rtc_ops; |
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rtc->rtc_dev->range_max = U32_MAX; |
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return devm_rtc_register_device(rtc->rtc_dev); |
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} |
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static const __maybe_unused struct of_device_id dc_dt_ids[] = { |
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{ .compatible = "cnxt,cx92755-rtc" }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, dc_dt_ids); |
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static struct platform_driver dc_rtc_driver = { |
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.driver = { |
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.name = "digicolor_rtc", |
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.of_match_table = of_match_ptr(dc_dt_ids), |
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}, |
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}; |
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module_platform_driver_probe(dc_rtc_driver, dc_rtc_probe); |
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MODULE_AUTHOR("Baruch Siach <[email protected]>"); |
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MODULE_DESCRIPTION("Conexant Digicolor Realtime Clock Driver (RTC)"); |
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MODULE_LICENSE("GPL");
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