// SPDX-License-Identifier: GPL-2.0 /* * Microchip MPFS RTC driver * * Copyright (c) 2021-2022 Microchip Corporation. All rights reserved. * * Author: Daire McNamara * & Conor Dooley */ #include "linux/bits.h" #include "linux/iopoll.h" #include #include #include #include #include #include #include #include #include #define CONTROL_REG 0x00 #define MODE_REG 0x04 #define PRESCALER_REG 0x08 #define ALARM_LOWER_REG 0x0c #define ALARM_UPPER_REG 0x10 #define COMPARE_LOWER_REG 0x14 #define COMPARE_UPPER_REG 0x18 #define DATETIME_LOWER_REG 0x20 #define DATETIME_UPPER_REG 0x24 #define CONTROL_RUNNING_BIT BIT(0) #define CONTROL_START_BIT BIT(0) #define CONTROL_STOP_BIT BIT(1) #define CONTROL_ALARM_ON_BIT BIT(2) #define CONTROL_ALARM_OFF_BIT BIT(3) #define CONTROL_RESET_BIT BIT(4) #define CONTROL_UPLOAD_BIT BIT(5) #define CONTROL_DOWNLOAD_BIT BIT(6) #define CONTROL_MATCH_BIT BIT(7) #define CONTROL_WAKEUP_CLR_BIT BIT(8) #define CONTROL_WAKEUP_SET_BIT BIT(9) #define CONTROL_UPDATED_BIT BIT(10) #define MODE_CLOCK_CALENDAR BIT(0) #define MODE_WAKE_EN BIT(1) #define MODE_WAKE_RESET BIT(2) #define MODE_WAKE_CONTINUE BIT(3) #define MAX_PRESCALER_COUNT GENMASK(25, 0) #define DATETIME_UPPER_MASK GENMASK(29, 0) #define ALARM_UPPER_MASK GENMASK(10, 0) #define UPLOAD_TIMEOUT_US 50 struct mpfs_rtc_dev { struct rtc_device *rtc; void __iomem *base; }; static void mpfs_rtc_start(struct mpfs_rtc_dev *rtcdev) { u32 ctrl; ctrl = readl(rtcdev->base + CONTROL_REG); ctrl &= ~CONTROL_STOP_BIT; ctrl |= CONTROL_START_BIT; writel(ctrl, rtcdev->base + CONTROL_REG); } static void mpfs_rtc_clear_irq(struct mpfs_rtc_dev *rtcdev) { u32 val = readl(rtcdev->base + CONTROL_REG); val &= ~(CONTROL_ALARM_ON_BIT | CONTROL_STOP_BIT); val |= CONTROL_ALARM_OFF_BIT; writel(val, rtcdev->base + CONTROL_REG); /* * Ensure that the posted write to the CONTROL_REG register completed before * returning from this function. Not doing this may result in the interrupt * only being cleared some time after this function returns. */ (void)readl(rtcdev->base + CONTROL_REG); } static int mpfs_rtc_readtime(struct device *dev, struct rtc_time *tm) { struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev); u64 time; time = readl(rtcdev->base + DATETIME_LOWER_REG); time |= ((u64)readl(rtcdev->base + DATETIME_UPPER_REG) & DATETIME_UPPER_MASK) << 32; rtc_time64_to_tm(time, tm); return 0; } static int mpfs_rtc_settime(struct device *dev, struct rtc_time *tm) { struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev); u32 ctrl, prog; u64 time; int ret; time = rtc_tm_to_time64(tm); writel((u32)time, rtcdev->base + DATETIME_LOWER_REG); writel((u32)(time >> 32) & DATETIME_UPPER_MASK, rtcdev->base + DATETIME_UPPER_REG); ctrl = readl(rtcdev->base + CONTROL_REG); ctrl &= ~CONTROL_STOP_BIT; ctrl |= CONTROL_UPLOAD_BIT; writel(ctrl, rtcdev->base + CONTROL_REG); ret = read_poll_timeout(readl, prog, prog & CONTROL_UPLOAD_BIT, 0, UPLOAD_TIMEOUT_US, false, rtcdev->base + CONTROL_REG); if (ret) { dev_err(dev, "timed out uploading time to rtc"); return ret; } mpfs_rtc_start(rtcdev); return 0; } static int mpfs_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) { struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev); u32 mode = readl(rtcdev->base + MODE_REG); u64 time; alrm->enabled = mode & MODE_WAKE_EN; time = (u64)readl(rtcdev->base + ALARM_LOWER_REG) << 32; time |= (readl(rtcdev->base + ALARM_UPPER_REG) & ALARM_UPPER_MASK); rtc_time64_to_tm(time, &alrm->time); return 0; } static int mpfs_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) { struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev); u32 mode, ctrl; u64 time; /* Disable the alarm before updating */ ctrl = readl(rtcdev->base + CONTROL_REG); ctrl |= CONTROL_ALARM_OFF_BIT; writel(ctrl, rtcdev->base + CONTROL_REG); time = rtc_tm_to_time64(&alrm->time); writel((u32)time, rtcdev->base + ALARM_LOWER_REG); writel((u32)(time >> 32) & ALARM_UPPER_MASK, rtcdev->base + ALARM_UPPER_REG); /* Bypass compare register in alarm mode */ writel(GENMASK(31, 0), rtcdev->base + COMPARE_LOWER_REG); writel(GENMASK(29, 0), rtcdev->base + COMPARE_UPPER_REG); /* Configure the RTC to enable the alarm. */ ctrl = readl(rtcdev->base + CONTROL_REG); mode = readl(rtcdev->base + MODE_REG); if (alrm->enabled) { mode = MODE_WAKE_EN | MODE_WAKE_CONTINUE; /* Enable the alarm */ ctrl &= ~CONTROL_ALARM_OFF_BIT; ctrl |= CONTROL_ALARM_ON_BIT; } ctrl &= ~CONTROL_STOP_BIT; ctrl |= CONTROL_START_BIT; writel(ctrl, rtcdev->base + CONTROL_REG); writel(mode, rtcdev->base + MODE_REG); return 0; } static int mpfs_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct mpfs_rtc_dev *rtcdev = dev_get_drvdata(dev); u32 ctrl; ctrl = readl(rtcdev->base + CONTROL_REG); ctrl &= ~(CONTROL_ALARM_ON_BIT | CONTROL_ALARM_OFF_BIT | CONTROL_STOP_BIT); if (enabled) ctrl |= CONTROL_ALARM_ON_BIT; else ctrl |= CONTROL_ALARM_OFF_BIT; writel(ctrl, rtcdev->base + CONTROL_REG); return 0; } static irqreturn_t mpfs_rtc_wakeup_irq_handler(int irq, void *dev) { struct mpfs_rtc_dev *rtcdev = dev; mpfs_rtc_clear_irq(rtcdev); rtc_update_irq(rtcdev->rtc, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; } static const struct rtc_class_ops mpfs_rtc_ops = { .read_time = mpfs_rtc_readtime, .set_time = mpfs_rtc_settime, .read_alarm = mpfs_rtc_readalarm, .set_alarm = mpfs_rtc_setalarm, .alarm_irq_enable = mpfs_rtc_alarm_irq_enable, }; static int mpfs_rtc_probe(struct platform_device *pdev) { struct mpfs_rtc_dev *rtcdev; struct clk *clk; unsigned long prescaler; int wakeup_irq, ret; rtcdev = devm_kzalloc(&pdev->dev, sizeof(struct mpfs_rtc_dev), GFP_KERNEL); if (!rtcdev) return -ENOMEM; platform_set_drvdata(pdev, rtcdev); rtcdev->rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtcdev->rtc)) return PTR_ERR(rtcdev->rtc); rtcdev->rtc->ops = &mpfs_rtc_ops; /* range is capped by alarm max, lower reg is 31:0 & upper is 10:0 */ rtcdev->rtc->range_max = GENMASK_ULL(42, 0); clk = devm_clk_get_enabled(&pdev->dev, "rtc"); if (IS_ERR(clk)) return PTR_ERR(clk); rtcdev->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(rtcdev->base)) { dev_dbg(&pdev->dev, "invalid ioremap resources\n"); return PTR_ERR(rtcdev->base); } wakeup_irq = platform_get_irq(pdev, 0); if (wakeup_irq <= 0) { dev_dbg(&pdev->dev, "could not get wakeup irq\n"); return wakeup_irq; } ret = devm_request_irq(&pdev->dev, wakeup_irq, mpfs_rtc_wakeup_irq_handler, 0, dev_name(&pdev->dev), rtcdev); if (ret) { dev_dbg(&pdev->dev, "could not request wakeup irq\n"); return ret; } /* prescaler hardware adds 1 to reg value */ prescaler = clk_get_rate(devm_clk_get(&pdev->dev, "rtcref")) - 1; if (prescaler > MAX_PRESCALER_COUNT) { dev_dbg(&pdev->dev, "invalid prescaler %lu\n", prescaler); return -EINVAL; } writel(prescaler, rtcdev->base + PRESCALER_REG); dev_info(&pdev->dev, "prescaler set to: %lu\n", prescaler); device_init_wakeup(&pdev->dev, true); ret = dev_pm_set_wake_irq(&pdev->dev, wakeup_irq); if (ret) dev_err(&pdev->dev, "failed to enable irq wake\n"); return devm_rtc_register_device(rtcdev->rtc); } static void mpfs_rtc_remove(struct platform_device *pdev) { dev_pm_clear_wake_irq(&pdev->dev); } static const struct of_device_id mpfs_rtc_of_match[] = { { .compatible = "microchip,mpfs-rtc" }, { } }; MODULE_DEVICE_TABLE(of, mpfs_rtc_of_match); static struct platform_driver mpfs_rtc_driver = { .probe = mpfs_rtc_probe, .remove_new = mpfs_rtc_remove, .driver = { .name = "mpfs_rtc", .of_match_table = mpfs_rtc_of_match, }, }; module_platform_driver(mpfs_rtc_driver); MODULE_DESCRIPTION("Real time clock for Microchip Polarfire SoC"); MODULE_AUTHOR("Daire McNamara "); MODULE_AUTHOR("Conor Dooley "); MODULE_LICENSE("GPL");