// SPDX-License-Identifier: GPL-2.0 /* * Real Time Clock (RTC) Driver for i.MX53 * Copyright (c) 2004-2011 Freescale Semiconductor, Inc. * Copyright (c) 2017 Beckhoff Automation GmbH & Co. KG */ #include #include #include #include #include #include #include #define SRTC_LPPDR_INIT 0x41736166 /* init for glitch detect */ #define SRTC_LPCR_EN_LP BIT(3) /* lp enable */ #define SRTC_LPCR_WAE BIT(4) /* lp wakeup alarm enable */ #define SRTC_LPCR_ALP BIT(7) /* lp alarm flag */ #define SRTC_LPCR_NSA BIT(11) /* lp non secure access */ #define SRTC_LPCR_NVE BIT(14) /* lp non valid state exit bit */ #define SRTC_LPCR_IE BIT(15) /* lp init state exit bit */ #define SRTC_LPSR_ALP BIT(3) /* lp alarm flag */ #define SRTC_LPSR_NVES BIT(14) /* lp non-valid state exit status */ #define SRTC_LPSR_IES BIT(15) /* lp init state exit status */ #define SRTC_LPSCMR 0x00 /* LP Secure Counter MSB Reg */ #define SRTC_LPSCLR 0x04 /* LP Secure Counter LSB Reg */ #define SRTC_LPSAR 0x08 /* LP Secure Alarm Reg */ #define SRTC_LPCR 0x10 /* LP Control Reg */ #define SRTC_LPSR 0x14 /* LP Status Reg */ #define SRTC_LPPDR 0x18 /* LP Power Supply Glitch Detector Reg */ /* max. number of retries to read registers, 120 was max during test */ #define REG_READ_TIMEOUT 2000 struct mxc_rtc_data { struct rtc_device *rtc; void __iomem *ioaddr; struct clk *clk; spinlock_t lock; /* protects register access */ int irq; }; /* * This function does write synchronization for writes to the lp srtc block. * To take care of the asynchronous CKIL clock, all writes from the IP domain * will be synchronized to the CKIL domain. * The caller should hold the pdata->lock */ static void mxc_rtc_sync_lp_locked(struct device *dev, void __iomem *ioaddr) { unsigned int i; /* Wait for 3 CKIL cycles */ for (i = 0; i < 3; i++) { const u32 count = readl(ioaddr + SRTC_LPSCLR); unsigned int timeout = REG_READ_TIMEOUT; while ((readl(ioaddr + SRTC_LPSCLR)) == count) { if (!--timeout) { dev_err_once(dev, "SRTC_LPSCLR stuck! Check your hw.\n"); return; } } } } /* This function is the RTC interrupt service routine. */ static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id) { struct device *dev = dev_id; struct mxc_rtc_data *pdata = dev_get_drvdata(dev); void __iomem *ioaddr = pdata->ioaddr; unsigned long flags; u32 lp_status; u32 lp_cr; spin_lock_irqsave(&pdata->lock, flags); if (clk_enable(pdata->clk)) { spin_unlock_irqrestore(&pdata->lock, flags); return IRQ_NONE; } lp_status = readl(ioaddr + SRTC_LPSR); lp_cr = readl(ioaddr + SRTC_LPCR); /* update irq data & counter */ if (lp_status & SRTC_LPSR_ALP) { if (lp_cr & SRTC_LPCR_ALP) rtc_update_irq(pdata->rtc, 1, RTC_AF | RTC_IRQF); /* disable further lp alarm interrupts */ lp_cr &= ~(SRTC_LPCR_ALP | SRTC_LPCR_WAE); } /* Update interrupt enables */ writel(lp_cr, ioaddr + SRTC_LPCR); /* clear interrupt status */ writel(lp_status, ioaddr + SRTC_LPSR); mxc_rtc_sync_lp_locked(dev, ioaddr); clk_disable(pdata->clk); spin_unlock_irqrestore(&pdata->lock, flags); return IRQ_HANDLED; } /* * Enable clk and aquire spinlock * @return 0 if successful; non-zero otherwise. */ static int mxc_rtc_lock(struct mxc_rtc_data *const pdata) { int ret; spin_lock_irq(&pdata->lock); ret = clk_enable(pdata->clk); if (ret) { spin_unlock_irq(&pdata->lock); return ret; } return 0; } static int mxc_rtc_unlock(struct mxc_rtc_data *const pdata) { clk_disable(pdata->clk); spin_unlock_irq(&pdata->lock); return 0; } /* * This function reads the current RTC time into tm in Gregorian date. * * @param tm contains the RTC time value upon return * * @return 0 if successful; non-zero otherwise. */ static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct mxc_rtc_data *pdata = dev_get_drvdata(dev); const int clk_failed = clk_enable(pdata->clk); if (!clk_failed) { const time64_t now = readl(pdata->ioaddr + SRTC_LPSCMR); rtc_time64_to_tm(now, tm); clk_disable(pdata->clk); return 0; } return clk_failed; } /* * This function sets the internal RTC time based on tm in Gregorian date. * * @param tm the time value to be set in the RTC * * @return 0 if successful; non-zero otherwise. */ static int mxc_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct mxc_rtc_data *pdata = dev_get_drvdata(dev); time64_t time = rtc_tm_to_time64(tm); int ret; ret = mxc_rtc_lock(pdata); if (ret) return ret; writel(time, pdata->ioaddr + SRTC_LPSCMR); mxc_rtc_sync_lp_locked(dev, pdata->ioaddr); return mxc_rtc_unlock(pdata); } /* * This function reads the current alarm value into the passed in \b alrm * argument. It updates the \b alrm's pending field value based on the whether * an alarm interrupt occurs or not. * * @param alrm contains the RTC alarm value upon return * * @return 0 if successful; non-zero otherwise. */ static int mxc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct mxc_rtc_data *pdata = dev_get_drvdata(dev); void __iomem *ioaddr = pdata->ioaddr; int ret; ret = mxc_rtc_lock(pdata); if (ret) return ret; rtc_time64_to_tm(readl(ioaddr + SRTC_LPSAR), &alrm->time); alrm->pending = !!(readl(ioaddr + SRTC_LPSR) & SRTC_LPSR_ALP); return mxc_rtc_unlock(pdata); } /* * Enable/Disable alarm interrupt * The caller should hold the pdata->lock */ static void mxc_rtc_alarm_irq_enable_locked(struct mxc_rtc_data *pdata, unsigned int enable) { u32 lp_cr = readl(pdata->ioaddr + SRTC_LPCR); if (enable) lp_cr |= (SRTC_LPCR_ALP | SRTC_LPCR_WAE); else lp_cr &= ~(SRTC_LPCR_ALP | SRTC_LPCR_WAE); writel(lp_cr, pdata->ioaddr + SRTC_LPCR); } static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) { struct mxc_rtc_data *pdata = dev_get_drvdata(dev); int ret = mxc_rtc_lock(pdata); if (ret) return ret; mxc_rtc_alarm_irq_enable_locked(pdata, enable); return mxc_rtc_unlock(pdata); } /* * This function sets the RTC alarm based on passed in alrm. * * @param alrm the alarm value to be set in the RTC * * @return 0 if successful; non-zero otherwise. */ static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { const time64_t time = rtc_tm_to_time64(&alrm->time); struct mxc_rtc_data *pdata = dev_get_drvdata(dev); int ret = mxc_rtc_lock(pdata); if (ret) return ret; writel((u32)time, pdata->ioaddr + SRTC_LPSAR); /* clear alarm interrupt status bit */ writel(SRTC_LPSR_ALP, pdata->ioaddr + SRTC_LPSR); mxc_rtc_sync_lp_locked(dev, pdata->ioaddr); mxc_rtc_alarm_irq_enable_locked(pdata, alrm->enabled); mxc_rtc_sync_lp_locked(dev, pdata->ioaddr); mxc_rtc_unlock(pdata); return ret; } static const struct rtc_class_ops mxc_rtc_ops = { .read_time = mxc_rtc_read_time, .set_time = mxc_rtc_set_time, .read_alarm = mxc_rtc_read_alarm, .set_alarm = mxc_rtc_set_alarm, .alarm_irq_enable = mxc_rtc_alarm_irq_enable, }; static int mxc_rtc_wait_for_flag(void __iomem *ioaddr, int flag) { unsigned int timeout = REG_READ_TIMEOUT; while (!(readl(ioaddr) & flag)) { if (!--timeout) return -EBUSY; } return 0; } static int mxc_rtc_probe(struct platform_device *pdev) { struct mxc_rtc_data *pdata; void __iomem *ioaddr; int ret = 0; pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return -ENOMEM; pdata->ioaddr = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(pdata->ioaddr)) return PTR_ERR(pdata->ioaddr); ioaddr = pdata->ioaddr; pdata->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(pdata->clk)) { dev_err(&pdev->dev, "unable to get rtc clock!\n"); return PTR_ERR(pdata->clk); } spin_lock_init(&pdata->lock); pdata->irq = platform_get_irq(pdev, 0); if (pdata->irq < 0) return pdata->irq; device_init_wakeup(&pdev->dev, 1); ret = dev_pm_set_wake_irq(&pdev->dev, pdata->irq); if (ret) dev_err(&pdev->dev, "failed to enable irq wake\n"); ret = clk_prepare_enable(pdata->clk); if (ret) return ret; /* initialize glitch detect */ writel(SRTC_LPPDR_INIT, ioaddr + SRTC_LPPDR); /* clear lp interrupt status */ writel(0xFFFFFFFF, ioaddr + SRTC_LPSR); /* move out of init state */ writel((SRTC_LPCR_IE | SRTC_LPCR_NSA), ioaddr + SRTC_LPCR); ret = mxc_rtc_wait_for_flag(ioaddr + SRTC_LPSR, SRTC_LPSR_IES); if (ret) { dev_err(&pdev->dev, "Timeout waiting for SRTC_LPSR_IES\n"); clk_disable_unprepare(pdata->clk); return ret; } /* move out of non-valid state */ writel((SRTC_LPCR_IE | SRTC_LPCR_NVE | SRTC_LPCR_NSA | SRTC_LPCR_EN_LP), ioaddr + SRTC_LPCR); ret = mxc_rtc_wait_for_flag(ioaddr + SRTC_LPSR, SRTC_LPSR_NVES); if (ret) { dev_err(&pdev->dev, "Timeout waiting for SRTC_LPSR_NVES\n"); clk_disable_unprepare(pdata->clk); return ret; } pdata->rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(pdata->rtc)) return PTR_ERR(pdata->rtc); pdata->rtc->ops = &mxc_rtc_ops; pdata->rtc->range_max = U32_MAX; clk_disable(pdata->clk); platform_set_drvdata(pdev, pdata); ret = devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt, 0, pdev->name, &pdev->dev); if (ret < 0) { dev_err(&pdev->dev, "interrupt not available.\n"); clk_unprepare(pdata->clk); return ret; } ret = rtc_register_device(pdata->rtc); if (ret < 0) clk_unprepare(pdata->clk); return ret; } static int mxc_rtc_remove(struct platform_device *pdev) { struct mxc_rtc_data *pdata = platform_get_drvdata(pdev); clk_disable_unprepare(pdata->clk); return 0; } static const struct of_device_id mxc_ids[] = { { .compatible = "fsl,imx53-rtc", }, {} }; static struct platform_driver mxc_rtc_driver = { .driver = { .name = "mxc_rtc_v2", .of_match_table = mxc_ids, }, .probe = mxc_rtc_probe, .remove = mxc_rtc_remove, }; module_platform_driver(mxc_rtc_driver); MODULE_AUTHOR("Freescale Semiconductor, Inc."); MODULE_DESCRIPTION("Real Time Clock (RTC) Driver for i.MX53"); MODULE_LICENSE("GPL");