338 строки
8.1 KiB
C
338 строки
8.1 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Freescale FlexTimer Module (FTM) alarm device driver.
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*
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* Copyright 2014 Freescale Semiconductor, Inc.
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* Copyright 2019 NXP
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*
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*/
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/platform_device.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/module.h>
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#include <linux/fsl/ftm.h>
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#include <linux/rtc.h>
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#include <linux/time.h>
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#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_MASK_SHIFT)
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/*
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* Select Fixed frequency clock (32KHz) as clock source
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* of FlexTimer Module
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*/
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#define FTM_SC_CLKS_FIXED_FREQ 0x02
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#define FIXED_FREQ_CLK 32000
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/* Select 128 (2^7) as divider factor */
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#define MAX_FREQ_DIV (1 << FTM_SC_PS_MASK)
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/* Maximum counter value in FlexTimer's CNT registers */
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#define MAX_COUNT_VAL 0xffff
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struct ftm_rtc {
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struct rtc_device *rtc_dev;
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void __iomem *base;
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bool big_endian;
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u32 alarm_freq;
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};
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static inline u32 rtc_readl(struct ftm_rtc *dev, u32 reg)
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{
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if (dev->big_endian)
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return ioread32be(dev->base + reg);
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else
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return ioread32(dev->base + reg);
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}
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static inline void rtc_writel(struct ftm_rtc *dev, u32 reg, u32 val)
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{
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if (dev->big_endian)
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iowrite32be(val, dev->base + reg);
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else
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iowrite32(val, dev->base + reg);
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}
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static inline void ftm_counter_enable(struct ftm_rtc *rtc)
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{
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u32 val;
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/* select and enable counter clock source */
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val = rtc_readl(rtc, FTM_SC);
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val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
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val |= (FTM_SC_PS_MASK | FTM_SC_CLK(FTM_SC_CLKS_FIXED_FREQ));
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rtc_writel(rtc, FTM_SC, val);
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}
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static inline void ftm_counter_disable(struct ftm_rtc *rtc)
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{
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u32 val;
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/* disable counter clock source */
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val = rtc_readl(rtc, FTM_SC);
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val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
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rtc_writel(rtc, FTM_SC, val);
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}
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static inline void ftm_irq_acknowledge(struct ftm_rtc *rtc)
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{
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unsigned int timeout = 100;
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/*
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*Fix errata A-007728 for flextimer
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* If the FTM counter reaches the FTM_MOD value between
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* the reading of the TOF bit and the writing of 0 to
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* the TOF bit, the process of clearing the TOF bit
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* does not work as expected when FTMx_CONF[NUMTOF] != 0
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* and the current TOF count is less than FTMx_CONF[NUMTOF].
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* If the above condition is met, the TOF bit remains set.
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* If the TOF interrupt is enabled (FTMx_SC[TOIE] = 1),the
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* TOF interrupt also remains asserted.
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*
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* Above is the errata discription
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*
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* In one word: software clearing TOF bit not works when
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* FTMx_CONF[NUMTOF] was seted as nonzero and FTM counter
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* reaches the FTM_MOD value.
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*
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* The workaround is clearing TOF bit until it works
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* (FTM counter doesn't always reache the FTM_MOD anyway),
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* which may cost some cycles.
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*/
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while ((FTM_SC_TOF & rtc_readl(rtc, FTM_SC)) && timeout--)
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rtc_writel(rtc, FTM_SC, rtc_readl(rtc, FTM_SC) & (~FTM_SC_TOF));
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}
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static inline void ftm_irq_enable(struct ftm_rtc *rtc)
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{
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u32 val;
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val = rtc_readl(rtc, FTM_SC);
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val |= FTM_SC_TOIE;
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rtc_writel(rtc, FTM_SC, val);
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}
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static inline void ftm_irq_disable(struct ftm_rtc *rtc)
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{
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u32 val;
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val = rtc_readl(rtc, FTM_SC);
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val &= ~FTM_SC_TOIE;
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rtc_writel(rtc, FTM_SC, val);
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}
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static inline void ftm_reset_counter(struct ftm_rtc *rtc)
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{
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/*
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* The CNT register contains the FTM counter value.
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* Reset clears the CNT register. Writing any value to COUNT
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* updates the counter with its initial value, CNTIN.
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*/
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rtc_writel(rtc, FTM_CNT, 0x00);
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}
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static void ftm_clean_alarm(struct ftm_rtc *rtc)
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{
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ftm_counter_disable(rtc);
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rtc_writel(rtc, FTM_CNTIN, 0x00);
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rtc_writel(rtc, FTM_MOD, ~0U);
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ftm_reset_counter(rtc);
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}
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static irqreturn_t ftm_rtc_alarm_interrupt(int irq, void *dev)
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{
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struct ftm_rtc *rtc = dev;
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ftm_irq_acknowledge(rtc);
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ftm_irq_disable(rtc);
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ftm_clean_alarm(rtc);
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return IRQ_HANDLED;
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}
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static int ftm_rtc_alarm_irq_enable(struct device *dev,
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unsigned int enabled)
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{
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struct ftm_rtc *rtc = dev_get_drvdata(dev);
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if (enabled)
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ftm_irq_enable(rtc);
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else
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ftm_irq_disable(rtc);
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return 0;
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}
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/*
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* Note:
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* The function is not really getting time from the RTC
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* since FlexTimer is not a RTC device, but we need to
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* get time to setup alarm, so we are using system time
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* for now.
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*/
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static int ftm_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct timespec64 ts64;
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ktime_get_real_ts64(&ts64);
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rtc_time_to_tm(ts64.tv_sec, tm);
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return 0;
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}
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static int ftm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
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{
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return 0;
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}
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/*
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* 1. Select fixed frequency clock (32KHz) as clock source;
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* 2. Select 128 (2^7) as divider factor;
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* So clock is 250 Hz (32KHz/128).
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*
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* 3. FlexTimer's CNT register is a 32bit register,
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* but the register's 16 bit as counter value,it's other 16 bit
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* is reserved.So minimum counter value is 0x0,maximum counter
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* value is 0xffff.
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* So max alarm value is 262 (65536 / 250) seconds
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*/
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static int ftm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
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{
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struct rtc_time tm;
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unsigned long now, alm_time, cycle;
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struct ftm_rtc *rtc = dev_get_drvdata(dev);
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ftm_rtc_read_time(dev, &tm);
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rtc_tm_to_time(&tm, &now);
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rtc_tm_to_time(&alm->time, &alm_time);
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ftm_clean_alarm(rtc);
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cycle = (alm_time - now) * rtc->alarm_freq;
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if (cycle > MAX_COUNT_VAL) {
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pr_err("Out of alarm range {0~262} seconds.\n");
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return -ERANGE;
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}
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ftm_irq_disable(rtc);
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/*
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* The counter increments until the value of MOD is reached,
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* at which point the counter is reloaded with the value of CNTIN.
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* The TOF (the overflow flag) bit is set when the FTM counter
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* changes from MOD to CNTIN. So we should using the cycle - 1.
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*/
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rtc_writel(rtc, FTM_MOD, cycle - 1);
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ftm_counter_enable(rtc);
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ftm_irq_enable(rtc);
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return 0;
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}
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static const struct rtc_class_ops ftm_rtc_ops = {
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.read_time = ftm_rtc_read_time,
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.read_alarm = ftm_rtc_read_alarm,
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.set_alarm = ftm_rtc_set_alarm,
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.alarm_irq_enable = ftm_rtc_alarm_irq_enable,
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};
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static int ftm_rtc_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct resource *r;
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int irq;
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int ret;
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struct ftm_rtc *rtc;
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rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
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if (unlikely(!rtc)) {
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dev_err(&pdev->dev, "cannot alloc memory for rtc\n");
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return -ENOMEM;
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}
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platform_set_drvdata(pdev, rtc);
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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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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!r) {
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dev_err(&pdev->dev, "cannot get resource for rtc\n");
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return -ENODEV;
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}
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rtc->base = devm_ioremap_resource(&pdev->dev, r);
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if (IS_ERR(rtc->base)) {
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dev_err(&pdev->dev, "cannot ioremap resource for rtc\n");
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return PTR_ERR(rtc->base);
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}
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irq = irq_of_parse_and_map(np, 0);
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if (irq <= 0) {
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dev_err(&pdev->dev, "unable to get IRQ from DT, %d\n", irq);
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return -EINVAL;
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}
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ret = devm_request_irq(&pdev->dev, irq, ftm_rtc_alarm_interrupt,
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IRQF_NO_SUSPEND, dev_name(&pdev->dev), rtc);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to request irq\n");
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return ret;
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}
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rtc->big_endian = of_property_read_bool(np, "big-endian");
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rtc->alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV;
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rtc->rtc_dev->ops = &ftm_rtc_ops;
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device_init_wakeup(&pdev->dev, true);
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ret = rtc_register_device(rtc->rtc_dev);
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if (ret) {
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dev_err(&pdev->dev, "can't register rtc device\n");
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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 const struct of_device_id ftm_rtc_match[] = {
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{ .compatible = "fsl,ls1012a-ftm-alarm", },
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{ .compatible = "fsl,ls1021a-ftm-alarm", },
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{ .compatible = "fsl,ls1028a-ftm-alarm", },
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{ .compatible = "fsl,ls1043a-ftm-alarm", },
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{ .compatible = "fsl,ls1046a-ftm-alarm", },
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{ .compatible = "fsl,ls1088a-ftm-alarm", },
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{ .compatible = "fsl,ls208xa-ftm-alarm", },
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{ .compatible = "fsl,lx2160a-ftm-alarm", },
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{ },
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};
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static struct platform_driver ftm_rtc_driver = {
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.probe = ftm_rtc_probe,
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.driver = {
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.name = "ftm-alarm",
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.of_match_table = ftm_rtc_match,
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},
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};
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static int __init ftm_alarm_init(void)
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{
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return platform_driver_register(&ftm_rtc_driver);
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}
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device_initcall(ftm_alarm_init);
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MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver");
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MODULE_AUTHOR("Biwen Li <biwen.li@nxp.com>");
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MODULE_LICENSE("GPL");
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