// SPDX-License-Identifier: GPL-2.0 /* * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver * * Copyright (C) 2015 Xilinx, Inc. * */ #include <linux/delay.h> #include <linux/init.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/rtc.h> /* RTC Registers */ #define RTC_SET_TM_WR 0x00 #define RTC_SET_TM_RD 0x04 #define RTC_CALIB_WR 0x08 #define RTC_CALIB_RD 0x0C #define RTC_CUR_TM 0x10 #define RTC_CUR_TICK 0x14 #define RTC_ALRM 0x18 #define RTC_INT_STS 0x20 #define RTC_INT_MASK 0x24 #define RTC_INT_EN 0x28 #define RTC_INT_DIS 0x2C #define RTC_CTRL 0x40 #define RTC_FR_EN BIT(20) #define RTC_FR_DATSHIFT 16 #define RTC_TICK_MASK 0xFFFF #define RTC_INT_SEC BIT(0) #define RTC_INT_ALRM BIT(1) #define RTC_OSC_EN BIT(24) #define RTC_BATT_EN BIT(31) #define RTC_CALIB_DEF 0x198233 #define RTC_CALIB_MASK 0x1FFFFF #define RTC_ALRM_MASK BIT(1) #define RTC_MSEC 1000 struct xlnx_rtc_dev { struct rtc_device *rtc; void __iomem *reg_base; int alarm_irq; int sec_irq; unsigned int calibval; }; static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); unsigned long new_time; /* * The value written will be updated after 1 sec into the * seconds read register, so we need to program time +1 sec * to get the correct time on read. */ new_time = rtc_tm_to_time64(tm) + 1; /* * Writing into calibration register will clear the Tick Counter and * force the next second to be signaled exactly in 1 second period */ xrtcdev->calibval &= RTC_CALIB_MASK; writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR); /* * Clear the rtc interrupt status register after setting the * time. During a read_time function, the code should read the * RTC_INT_STATUS register and if bit 0 is still 0, it means * that one second has not elapsed yet since RTC was set and * the current time should be read from SET_TIME_READ register; * otherwise, CURRENT_TIME register is read to report the time */ writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS); return 0; } static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm) { u32 status; unsigned long read_time; struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); status = readl(xrtcdev->reg_base + RTC_INT_STS); if (status & RTC_INT_SEC) { /* * RTC has updated the CURRENT_TIME with the time written into * SET_TIME_WRITE register. */ read_time = readl(xrtcdev->reg_base + RTC_CUR_TM); } else { /* * Time written in SET_TIME_WRITE has not yet updated into * the seconds read register, so read the time from the * SET_TIME_WRITE instead of CURRENT_TIME register. * Since we add +1 sec while writing, we need to -1 sec while * reading. */ read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1; } rtc_time64_to_tm(read_time, tm); return 0; } static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time); alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM; return 0; } static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled) { struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); unsigned int status; ulong timeout; timeout = jiffies + msecs_to_jiffies(RTC_MSEC); if (enabled) { while (1) { status = readl(xrtcdev->reg_base + RTC_INT_STS); if (!((status & RTC_ALRM_MASK) == RTC_ALRM_MASK)) break; if (time_after_eq(jiffies, timeout)) { dev_err(dev, "Time out occur, while clearing alarm status bit\n"); return -ETIMEDOUT; } writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS); } writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN); } else { writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS); } return 0; } static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); unsigned long alarm_time; alarm_time = rtc_tm_to_time64(&alrm->time); writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM)); xlnx_rtc_alarm_irq_enable(dev, alrm->enabled); return 0; } static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev) { u32 rtc_ctrl; /* Enable RTC switch to battery when VCC_PSAUX is not available */ rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL); rtc_ctrl |= RTC_BATT_EN; writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL); /* * Based on crystal freq of 33.330 KHz * set the seconds counter and enable, set fractions counter * to default value suggested as per design spec * to correct RTC delay in frequency over period of time. */ xrtcdev->calibval &= RTC_CALIB_MASK; writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); } static const struct rtc_class_ops xlnx_rtc_ops = { .set_time = xlnx_rtc_set_time, .read_time = xlnx_rtc_read_time, .read_alarm = xlnx_rtc_read_alarm, .set_alarm = xlnx_rtc_set_alarm, .alarm_irq_enable = xlnx_rtc_alarm_irq_enable, }; static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) { struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id; unsigned int status; status = readl(xrtcdev->reg_base + RTC_INT_STS); /* Check if interrupt asserted */ if (!(status & (RTC_INT_SEC | RTC_INT_ALRM))) return IRQ_NONE; /* Disable RTC_INT_ALRM interrupt only */ writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS); if (status & RTC_INT_ALRM) rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; } static int xlnx_rtc_probe(struct platform_device *pdev) { struct xlnx_rtc_dev *xrtcdev; int ret; xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL); if (!xrtcdev) return -ENOMEM; platform_set_drvdata(pdev, xrtcdev); xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(xrtcdev->rtc)) return PTR_ERR(xrtcdev->rtc); xrtcdev->rtc->ops = &xlnx_rtc_ops; xrtcdev->rtc->range_max = U32_MAX; xrtcdev->reg_base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(xrtcdev->reg_base)) return PTR_ERR(xrtcdev->reg_base); xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm"); if (xrtcdev->alarm_irq < 0) return xrtcdev->alarm_irq; ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq, xlnx_rtc_interrupt, 0, dev_name(&pdev->dev), xrtcdev); if (ret) { dev_err(&pdev->dev, "request irq failed\n"); return ret; } xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec"); if (xrtcdev->sec_irq < 0) return xrtcdev->sec_irq; ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq, xlnx_rtc_interrupt, 0, dev_name(&pdev->dev), xrtcdev); if (ret) { dev_err(&pdev->dev, "request irq failed\n"); return ret; } ret = of_property_read_u32(pdev->dev.of_node, "calibration", &xrtcdev->calibval); if (ret) xrtcdev->calibval = RTC_CALIB_DEF; xlnx_init_rtc(xrtcdev); device_init_wakeup(&pdev->dev, 1); return devm_rtc_register_device(xrtcdev->rtc); } static int xlnx_rtc_remove(struct platform_device *pdev) { xlnx_rtc_alarm_irq_enable(&pdev->dev, 0); device_init_wakeup(&pdev->dev, 0); return 0; } static int __maybe_unused xlnx_rtc_suspend(struct device *dev) { struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); if (device_may_wakeup(dev)) enable_irq_wake(xrtcdev->alarm_irq); else xlnx_rtc_alarm_irq_enable(dev, 0); return 0; } static int __maybe_unused xlnx_rtc_resume(struct device *dev) { struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); if (device_may_wakeup(dev)) disable_irq_wake(xrtcdev->alarm_irq); else xlnx_rtc_alarm_irq_enable(dev, 1); return 0; } static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume); static const struct of_device_id xlnx_rtc_of_match[] = { {.compatible = "xlnx,zynqmp-rtc" }, { } }; MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match); static struct platform_driver xlnx_rtc_driver = { .probe = xlnx_rtc_probe, .remove = xlnx_rtc_remove, .driver = { .name = KBUILD_MODNAME, .pm = &xlnx_rtc_pm_ops, .of_match_table = xlnx_rtc_of_match, }, }; module_platform_driver(xlnx_rtc_driver); MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver"); MODULE_AUTHOR("Xilinx Inc."); MODULE_LICENSE("GPL v2");