250 lines
6.2 KiB
C
250 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Real time clocks driver for MStar/SigmaStar ARMv7 SoCs.
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* Based on "Real Time Clock driver for msb252x." that was contained
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* in various MStar kernels.
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*
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* (C) 2019 Daniel Palmer
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* (C) 2021 Romain Perier
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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/* Registers */
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#define REG_RTC_CTRL 0x00
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#define REG_RTC_FREQ_CW_L 0x04
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#define REG_RTC_FREQ_CW_H 0x08
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#define REG_RTC_LOAD_VAL_L 0x0C
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#define REG_RTC_LOAD_VAL_H 0x10
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#define REG_RTC_MATCH_VAL_L 0x14
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#define REG_RTC_MATCH_VAL_H 0x18
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#define REG_RTC_STATUS_INT 0x1C
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#define REG_RTC_CNT_VAL_L 0x20
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#define REG_RTC_CNT_VAL_H 0x24
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/* Control bits for REG_RTC_CTRL */
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#define SOFT_RSTZ_BIT BIT(0)
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#define CNT_EN_BIT BIT(1)
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#define WRAP_EN_BIT BIT(2)
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#define LOAD_EN_BIT BIT(3)
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#define READ_EN_BIT BIT(4)
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#define INT_MASK_BIT BIT(5)
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#define INT_FORCE_BIT BIT(6)
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#define INT_CLEAR_BIT BIT(7)
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/* Control bits for REG_RTC_STATUS_INT */
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#define RAW_INT_BIT BIT(0)
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#define ALM_INT_BIT BIT(1)
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struct msc313_rtc {
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struct rtc_device *rtc_dev;
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void __iomem *rtc_base;
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};
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static int msc313_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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struct msc313_rtc *priv = dev_get_drvdata(dev);
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unsigned long seconds;
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seconds = readw(priv->rtc_base + REG_RTC_MATCH_VAL_L)
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| ((unsigned long)readw(priv->rtc_base + REG_RTC_MATCH_VAL_H) << 16);
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rtc_time64_to_tm(seconds, &alarm->time);
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if (!(readw(priv->rtc_base + REG_RTC_CTRL) & INT_MASK_BIT))
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alarm->enabled = 1;
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return 0;
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}
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static int msc313_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
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{
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struct msc313_rtc *priv = dev_get_drvdata(dev);
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u16 reg;
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reg = readw(priv->rtc_base + REG_RTC_CTRL);
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if (enabled)
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reg &= ~INT_MASK_BIT;
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else
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reg |= INT_MASK_BIT;
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writew(reg, priv->rtc_base + REG_RTC_CTRL);
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return 0;
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}
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static int msc313_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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struct msc313_rtc *priv = dev_get_drvdata(dev);
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unsigned long seconds;
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seconds = rtc_tm_to_time64(&alarm->time);
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writew((seconds & 0xFFFF), priv->rtc_base + REG_RTC_MATCH_VAL_L);
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writew((seconds >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_MATCH_VAL_H);
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msc313_rtc_alarm_irq_enable(dev, alarm->enabled);
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return 0;
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}
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static bool msc313_rtc_get_enabled(struct msc313_rtc *priv)
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{
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return readw(priv->rtc_base + REG_RTC_CTRL) & CNT_EN_BIT;
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}
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static void msc313_rtc_set_enabled(struct msc313_rtc *priv)
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{
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u16 reg;
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reg = readw(priv->rtc_base + REG_RTC_CTRL);
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reg |= CNT_EN_BIT;
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writew(reg, priv->rtc_base + REG_RTC_CTRL);
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}
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static int msc313_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct msc313_rtc *priv = dev_get_drvdata(dev);
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u32 seconds;
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u16 reg;
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if (!msc313_rtc_get_enabled(priv))
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return -EINVAL;
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reg = readw(priv->rtc_base + REG_RTC_CTRL);
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writew(reg | READ_EN_BIT, priv->rtc_base + REG_RTC_CTRL);
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/* Wait for HW latch done */
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while (readw(priv->rtc_base + REG_RTC_CTRL) & READ_EN_BIT)
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udelay(1);
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seconds = readw(priv->rtc_base + REG_RTC_CNT_VAL_L)
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| ((unsigned long)readw(priv->rtc_base + REG_RTC_CNT_VAL_H) << 16);
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rtc_time64_to_tm(seconds, tm);
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return 0;
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}
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static int msc313_rtc_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct msc313_rtc *priv = dev_get_drvdata(dev);
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unsigned long seconds;
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u16 reg;
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seconds = rtc_tm_to_time64(tm);
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writew(seconds & 0xFFFF, priv->rtc_base + REG_RTC_LOAD_VAL_L);
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writew((seconds >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_LOAD_VAL_H);
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/* Enable load for loading value into internal RTC counter */
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reg = readw(priv->rtc_base + REG_RTC_CTRL);
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writew(reg | LOAD_EN_BIT, priv->rtc_base + REG_RTC_CTRL);
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/* Wait for HW latch done */
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while (readw(priv->rtc_base + REG_RTC_CTRL) & LOAD_EN_BIT)
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udelay(1);
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msc313_rtc_set_enabled(priv);
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return 0;
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}
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static const struct rtc_class_ops msc313_rtc_ops = {
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.read_time = msc313_rtc_read_time,
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.set_time = msc313_rtc_set_time,
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.read_alarm = msc313_rtc_read_alarm,
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.set_alarm = msc313_rtc_set_alarm,
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.alarm_irq_enable = msc313_rtc_alarm_irq_enable,
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};
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static irqreturn_t msc313_rtc_interrupt(s32 irq, void *dev_id)
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{
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struct msc313_rtc *priv = dev_get_drvdata(dev_id);
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u16 reg;
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reg = readw(priv->rtc_base + REG_RTC_STATUS_INT);
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if (!(reg & ALM_INT_BIT))
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return IRQ_NONE;
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reg = readw(priv->rtc_base + REG_RTC_CTRL);
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reg |= INT_CLEAR_BIT;
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reg &= ~INT_FORCE_BIT;
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writew(reg, priv->rtc_base + REG_RTC_CTRL);
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rtc_update_irq(priv->rtc_dev, 1, RTC_IRQF | RTC_AF);
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return IRQ_HANDLED;
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}
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static int msc313_rtc_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct msc313_rtc *priv;
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unsigned long rate;
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struct clk *clk;
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int ret;
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int irq;
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priv = devm_kzalloc(&pdev->dev, sizeof(struct msc313_rtc), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->rtc_base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(priv->rtc_base))
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return PTR_ERR(priv->rtc_base);
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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return -EINVAL;
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priv->rtc_dev = devm_rtc_allocate_device(dev);
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if (IS_ERR(priv->rtc_dev))
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return PTR_ERR(priv->rtc_dev);
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priv->rtc_dev->ops = &msc313_rtc_ops;
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priv->rtc_dev->range_max = U32_MAX;
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ret = devm_request_irq(dev, irq, msc313_rtc_interrupt, IRQF_SHARED,
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dev_name(&pdev->dev), &pdev->dev);
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if (ret) {
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dev_err(dev, "Could not request IRQ\n");
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return ret;
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}
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clk = devm_clk_get_enabled(dev, NULL);
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if (IS_ERR(clk)) {
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dev_err(dev, "No input reference clock\n");
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return PTR_ERR(clk);
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}
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rate = clk_get_rate(clk);
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writew(rate & 0xFFFF, priv->rtc_base + REG_RTC_FREQ_CW_L);
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writew((rate >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_FREQ_CW_H);
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platform_set_drvdata(pdev, priv);
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return devm_rtc_register_device(priv->rtc_dev);
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}
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static const struct of_device_id msc313_rtc_of_match_table[] = {
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{ .compatible = "mstar,msc313-rtc" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, msc313_rtc_of_match_table);
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static struct platform_driver msc313_rtc_driver = {
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.probe = msc313_rtc_probe,
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.driver = {
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.name = "msc313-rtc",
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.of_match_table = msc313_rtc_of_match_table,
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},
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};
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module_platform_driver(msc313_rtc_driver);
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MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
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MODULE_AUTHOR("Romain Perier <romain.perier@gmail.com>");
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MODULE_DESCRIPTION("MStar RTC Driver");
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MODULE_LICENSE("GPL v2");
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