// SPDX-License-Identifier: GPL-2.0+ /* * Realtek RTD129x RTC * * Copyright (c) 2017 Andreas Färber */ #include <linux/clk.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/rtc.h> #include <linux/spinlock.h> #define RTD_RTCSEC 0x00 #define RTD_RTCMIN 0x04 #define RTD_RTCHR 0x08 #define RTD_RTCDATE1 0x0c #define RTD_RTCDATE2 0x10 #define RTD_RTCACR 0x28 #define RTD_RTCEN 0x2c #define RTD_RTCCR 0x30 #define RTD_RTCSEC_RTCSEC_MASK 0x7f #define RTD_RTCMIN_RTCMIN_MASK 0x3f #define RTD_RTCHR_RTCHR_MASK 0x1f #define RTD_RTCDATE1_RTCDATE1_MASK 0xff #define RTD_RTCDATE2_RTCDATE2_MASK 0x7f #define RTD_RTCACR_RTCPWR BIT(7) #define RTD_RTCEN_RTCEN_MASK 0xff #define RTD_RTCCR_RTCRST BIT(6) struct rtd119x_rtc { void __iomem *base; struct clk *clk; struct rtc_device *rtcdev; unsigned int base_year; }; static inline int rtd119x_rtc_days_in_year(int year) { return 365 + (is_leap_year(year) ? 1 : 0); } static void rtd119x_rtc_reset(struct device *dev) { struct rtd119x_rtc *data = dev_get_drvdata(dev); u32 val; val = readl_relaxed(data->base + RTD_RTCCR); val |= RTD_RTCCR_RTCRST; writel_relaxed(val, data->base + RTD_RTCCR); val &= ~RTD_RTCCR_RTCRST; writel(val, data->base + RTD_RTCCR); } static void rtd119x_rtc_set_enabled(struct device *dev, bool enable) { struct rtd119x_rtc *data = dev_get_drvdata(dev); u32 val; val = readl_relaxed(data->base + RTD_RTCEN); if (enable) { if ((val & RTD_RTCEN_RTCEN_MASK) == 0x5a) return; writel_relaxed(0x5a, data->base + RTD_RTCEN); } else { writel_relaxed(0, data->base + RTD_RTCEN); } } static int rtd119x_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct rtd119x_rtc *data = dev_get_drvdata(dev); s32 day; u32 sec; unsigned int year; int tries = 0; while (true) { tm->tm_sec = (readl_relaxed(data->base + RTD_RTCSEC) & RTD_RTCSEC_RTCSEC_MASK) >> 1; tm->tm_min = readl_relaxed(data->base + RTD_RTCMIN) & RTD_RTCMIN_RTCMIN_MASK; tm->tm_hour = readl_relaxed(data->base + RTD_RTCHR) & RTD_RTCHR_RTCHR_MASK; day = readl_relaxed(data->base + RTD_RTCDATE1) & RTD_RTCDATE1_RTCDATE1_MASK; day |= (readl_relaxed(data->base + RTD_RTCDATE2) & RTD_RTCDATE2_RTCDATE2_MASK) << 8; sec = (readl_relaxed(data->base + RTD_RTCSEC) & RTD_RTCSEC_RTCSEC_MASK) >> 1; tries++; if (sec == tm->tm_sec) break; if (tries >= 3) return -EINVAL; } if (tries > 1) dev_dbg(dev, "%s: needed %i tries\n", __func__, tries); year = data->base_year; while (day >= rtd119x_rtc_days_in_year(year)) { day -= rtd119x_rtc_days_in_year(year); year++; } tm->tm_year = year - 1900; tm->tm_yday = day; tm->tm_mon = 0; while (day >= rtc_month_days(tm->tm_mon, year)) { day -= rtc_month_days(tm->tm_mon, year); tm->tm_mon++; } tm->tm_mday = day + 1; return 0; } static int rtd119x_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct rtd119x_rtc *data = dev_get_drvdata(dev); unsigned int day; int i; if (1900 + tm->tm_year < data->base_year) return -EINVAL; day = 0; for (i = data->base_year; i < 1900 + tm->tm_year; i++) day += rtd119x_rtc_days_in_year(i); day += tm->tm_yday; if (day > 0x7fff) return -EINVAL; rtd119x_rtc_set_enabled(dev, false); writel_relaxed((tm->tm_sec << 1) & RTD_RTCSEC_RTCSEC_MASK, data->base + RTD_RTCSEC); writel_relaxed(tm->tm_min & RTD_RTCMIN_RTCMIN_MASK, data->base + RTD_RTCMIN); writel_relaxed(tm->tm_hour & RTD_RTCHR_RTCHR_MASK, data->base + RTD_RTCHR); writel_relaxed(day & RTD_RTCDATE1_RTCDATE1_MASK, data->base + RTD_RTCDATE1); writel_relaxed((day >> 8) & RTD_RTCDATE2_RTCDATE2_MASK, data->base + RTD_RTCDATE2); rtd119x_rtc_set_enabled(dev, true); return 0; } static const struct rtc_class_ops rtd119x_rtc_ops = { .read_time = rtd119x_rtc_read_time, .set_time = rtd119x_rtc_set_time, }; static const struct of_device_id rtd119x_rtc_dt_ids[] = { { .compatible = "realtek,rtd1295-rtc" }, { } }; static int rtd119x_rtc_probe(struct platform_device *pdev) { struct rtd119x_rtc *data; u32 val; int ret; data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; platform_set_drvdata(pdev, data); data->base_year = 2014; data->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(data->base)) return PTR_ERR(data->base); data->clk = of_clk_get(pdev->dev.of_node, 0); if (IS_ERR(data->clk)) return PTR_ERR(data->clk); ret = clk_prepare_enable(data->clk); if (ret) { clk_put(data->clk); return ret; } val = readl_relaxed(data->base + RTD_RTCACR); if (!(val & RTD_RTCACR_RTCPWR)) { writel_relaxed(RTD_RTCACR_RTCPWR, data->base + RTD_RTCACR); rtd119x_rtc_reset(&pdev->dev); writel_relaxed(0, data->base + RTD_RTCMIN); writel_relaxed(0, data->base + RTD_RTCHR); writel_relaxed(0, data->base + RTD_RTCDATE1); writel_relaxed(0, data->base + RTD_RTCDATE2); } rtd119x_rtc_set_enabled(&pdev->dev, true); data->rtcdev = devm_rtc_device_register(&pdev->dev, "rtc", &rtd119x_rtc_ops, THIS_MODULE); if (IS_ERR(data->rtcdev)) { dev_err(&pdev->dev, "failed to register rtc device"); clk_disable_unprepare(data->clk); clk_put(data->clk); return PTR_ERR(data->rtcdev); } return 0; } static int rtd119x_rtc_remove(struct platform_device *pdev) { struct rtd119x_rtc *data = platform_get_drvdata(pdev); rtd119x_rtc_set_enabled(&pdev->dev, false); clk_disable_unprepare(data->clk); clk_put(data->clk); return 0; } static struct platform_driver rtd119x_rtc_driver = { .probe = rtd119x_rtc_probe, .remove = rtd119x_rtc_remove, .driver = { .name = "rtd1295-rtc", .of_match_table = rtd119x_rtc_dt_ids, }, }; builtin_platform_driver(rtd119x_rtc_driver);