drivers/rtc/rtc-lpc24xx.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC)
0004  *
0005  * Copyright (C) 2011 NXP Semiconductors
0006  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
0007  */
0008
0009 #include <linux/clk.h>
0010 #include <linux/io.h>
0011 #include <linux/kernel.h>
0012 #include <linux/module.h>
0013 #include <linux/of.h>
0014 #include <linux/of_device.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/rtc.h>
0017
0018 /* LPC24xx RTC register offsets and bits */
0019 #define LPC24XX_ILR     0x00
0020 #define  LPC24XX_RTCCIF     BIT(0)
0021 #define  LPC24XX_RTCALF     BIT(1)
0022 #define LPC24XX_CTC     0x04
0023 #define LPC24XX_CCR     0x08
0024 #define  LPC24XX_CLKEN      BIT(0)
0025 #define  LPC178X_CCALEN     BIT(4)
0026 #define LPC24XX_CIIR        0x0c
0027 #define LPC24XX_AMR     0x10
0028 #define  LPC24XX_ALARM_DISABLE  0xff
0029 #define LPC24XX_CTIME0      0x14
0030 #define LPC24XX_CTIME1      0x18
0031 #define LPC24XX_CTIME2      0x1c
0032 #define LPC24XX_SEC     0x20
0033 #define LPC24XX_MIN     0x24
0034 #define LPC24XX_HOUR        0x28
0035 #define LPC24XX_DOM     0x2c
0036 #define LPC24XX_DOW     0x30
0037 #define LPC24XX_DOY     0x34
0038 #define LPC24XX_MONTH       0x38
0039 #define LPC24XX_YEAR        0x3c
0040 #define LPC24XX_ALSEC       0x60
0041 #define LPC24XX_ALMIN       0x64
0042 #define LPC24XX_ALHOUR      0x68
0043 #define LPC24XX_ALDOM       0x6c
0044 #define LPC24XX_ALDOW       0x70
0045 #define LPC24XX_ALDOY       0x74
0046 #define LPC24XX_ALMON       0x78
0047 #define LPC24XX_ALYEAR      0x7c
0048
0049 /* Macros to read fields in consolidated time (CT) registers */
0050 #define CT0_SECS(x)     (((x) >> 0)  & 0x3f)
0051 #define CT0_MINS(x)     (((x) >> 8)  & 0x3f)
0052 #define CT0_HOURS(x)        (((x) >> 16) & 0x1f)
0053 #define CT0_DOW(x)      (((x) >> 24) & 0x07)
0054 #define CT1_DOM(x)      (((x) >> 0)  & 0x1f)
0055 #define CT1_MONTH(x)        (((x) >> 8)  & 0x0f)
0056 #define CT1_YEAR(x)     (((x) >> 16) & 0xfff)
0057 #define CT2_DOY(x)      (((x) >> 0)  & 0xfff)
0058
0059 #define rtc_readl(dev, reg)     readl((dev)->rtc_base + (reg))
0060 #define rtc_writel(dev, reg, val)   writel((val), (dev)->rtc_base + (reg))
0061
0062 struct lpc24xx_rtc {
0063     void __iomem *rtc_base;
0064     struct rtc_device *rtc;
0065     struct clk *clk_rtc;
0066     struct clk *clk_reg;
0067 };
0068
0069 static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
0070 {
0071     struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
0072
0073     /* Disable RTC during update */
0074     rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
0075
0076     rtc_writel(rtc, LPC24XX_SEC,    tm->tm_sec);
0077     rtc_writel(rtc, LPC24XX_MIN,    tm->tm_min);
0078     rtc_writel(rtc, LPC24XX_HOUR,   tm->tm_hour);
0079     rtc_writel(rtc, LPC24XX_DOW,    tm->tm_wday);
0080     rtc_writel(rtc, LPC24XX_DOM,    tm->tm_mday);
0081     rtc_writel(rtc, LPC24XX_DOY,    tm->tm_yday);
0082     rtc_writel(rtc, LPC24XX_MONTH,  tm->tm_mon);
0083     rtc_writel(rtc, LPC24XX_YEAR,   tm->tm_year);
0084
0085     rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
0086
0087     return 0;
0088 }
0089
0090 static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
0091 {
0092     struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
0093     u32 ct0, ct1, ct2;
0094
0095     ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
0096     ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
0097     ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
0098
0099     tm->tm_sec  = CT0_SECS(ct0);
0100     tm->tm_min  = CT0_MINS(ct0);
0101     tm->tm_hour = CT0_HOURS(ct0);
0102     tm->tm_wday = CT0_DOW(ct0);
0103     tm->tm_mon  = CT1_MONTH(ct1);
0104     tm->tm_mday = CT1_DOM(ct1);
0105     tm->tm_year = CT1_YEAR(ct1);
0106     tm->tm_yday = CT2_DOY(ct2);
0107
0108     return 0;
0109 }
0110
0111 static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
0112 {
0113     struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
0114     struct rtc_time *tm = &wkalrm->time;
0115
0116     tm->tm_sec  = rtc_readl(rtc, LPC24XX_ALSEC);
0117     tm->tm_min  = rtc_readl(rtc, LPC24XX_ALMIN);
0118     tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
0119     tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
0120     tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
0121     tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
0122     tm->tm_mon  = rtc_readl(rtc, LPC24XX_ALMON);
0123     tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
0124
0125     wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
0126     wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
0127
0128     return rtc_valid_tm(&wkalrm->time);
0129 }
0130
0131 static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
0132 {
0133     struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
0134     struct rtc_time *tm = &wkalrm->time;
0135
0136     /* Disable alarm irq during update */
0137     rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
0138
0139     rtc_writel(rtc, LPC24XX_ALSEC,  tm->tm_sec);
0140     rtc_writel(rtc, LPC24XX_ALMIN,  tm->tm_min);
0141     rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
0142     rtc_writel(rtc, LPC24XX_ALDOM,  tm->tm_mday);
0143     rtc_writel(rtc, LPC24XX_ALDOW,  tm->tm_wday);
0144     rtc_writel(rtc, LPC24XX_ALDOY,  tm->tm_yday);
0145     rtc_writel(rtc, LPC24XX_ALMON,  tm->tm_mon);
0146     rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
0147
0148     if (wkalrm->enabled)
0149         rtc_writel(rtc, LPC24XX_AMR, 0);
0150
0151     return 0;
0152 }
0153
0154 static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
0155 {
0156     struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
0157
0158     if (enable)
0159         rtc_writel(rtc, LPC24XX_AMR, 0);
0160     else
0161         rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
0162
0163     return 0;
0164 }
0165
0166 static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data)
0167 {
0168     unsigned long events = RTC_IRQF;
0169     struct lpc24xx_rtc *rtc = data;
0170     u32 rtc_iir;
0171
0172     /* Check interrupt cause */
0173     rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
0174     if (rtc_iir & LPC24XX_RTCALF) {
0175         events |= RTC_AF;
0176         rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
0177     }
0178
0179     /* Clear interrupt status and report event */
0180     rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
0181     rtc_update_irq(rtc->rtc, 1, events);
0182
0183     return IRQ_HANDLED;
0184 }
0185
0186 static const struct rtc_class_ops lpc24xx_rtc_ops = {
0187     .read_time      = lpc24xx_rtc_read_time,
0188     .set_time       = lpc24xx_rtc_set_time,
0189     .read_alarm     = lpc24xx_rtc_read_alarm,
0190     .set_alarm      = lpc24xx_rtc_set_alarm,
0191     .alarm_irq_enable   = lpc24xx_rtc_alarm_irq_enable,
0192 };
0193
0194 static int lpc24xx_rtc_probe(struct platform_device *pdev)
0195 {
0196     struct lpc24xx_rtc *rtc;
0197     int irq, ret;
0198
0199     rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
0200     if (!rtc)
0201         return -ENOMEM;
0202
0203     rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
0204     if (IS_ERR(rtc->rtc_base))
0205         return PTR_ERR(rtc->rtc_base);
0206
0207     irq = platform_get_irq(pdev, 0);
0208     if (irq < 0)
0209         return irq;
0210
0211     rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
0212     if (IS_ERR(rtc->clk_rtc)) {
0213         dev_err(&pdev->dev, "error getting rtc clock\n");
0214         return PTR_ERR(rtc->clk_rtc);
0215     }
0216
0217     rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
0218     if (IS_ERR(rtc->clk_reg)) {
0219         dev_err(&pdev->dev, "error getting reg clock\n");
0220         return PTR_ERR(rtc->clk_reg);
0221     }
0222
0223     ret = clk_prepare_enable(rtc->clk_rtc);
0224     if (ret) {
0225         dev_err(&pdev->dev, "unable to enable rtc clock\n");
0226         return ret;
0227     }
0228
0229     ret = clk_prepare_enable(rtc->clk_reg);
0230     if (ret) {
0231         dev_err(&pdev->dev, "unable to enable reg clock\n");
0232         goto disable_rtc_clk;
0233     }
0234
0235     platform_set_drvdata(pdev, rtc);
0236
0237     /* Clear any pending interrupts */
0238     rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF);
0239
0240     /* Enable RTC count */
0241     rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
0242
0243     ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
0244                    pdev->name, rtc);
0245     if (ret < 0) {
0246         dev_warn(&pdev->dev, "can't request interrupt\n");
0247         goto disable_clks;
0248     }
0249
0250     rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc",
0251                         &lpc24xx_rtc_ops, THIS_MODULE);
0252     if (IS_ERR(rtc->rtc)) {
0253         dev_err(&pdev->dev, "can't register rtc device\n");
0254         ret = PTR_ERR(rtc->rtc);
0255         goto disable_clks;
0256     }
0257
0258     return 0;
0259
0260 disable_clks:
0261     clk_disable_unprepare(rtc->clk_reg);
0262 disable_rtc_clk:
0263     clk_disable_unprepare(rtc->clk_rtc);
0264     return ret;
0265 }
0266
0267 static int lpc24xx_rtc_remove(struct platform_device *pdev)
0268 {
0269     struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
0270
0271     /* Ensure all interrupt sources are masked */
0272     rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
0273     rtc_writel(rtc, LPC24XX_CIIR, 0);
0274
0275     rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
0276
0277     clk_disable_unprepare(rtc->clk_rtc);
0278     clk_disable_unprepare(rtc->clk_reg);
0279
0280     return 0;
0281 }
0282
0283 static const struct of_device_id lpc24xx_rtc_match[] = {
0284     { .compatible = "nxp,lpc1788-rtc" },
0285     { }
0286 };
0287 MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
0288
0289 static struct platform_driver lpc24xx_rtc_driver = {
0290     .probe  = lpc24xx_rtc_probe,
0291     .remove = lpc24xx_rtc_remove,
0292     .driver = {
0293         .name = "lpc24xx-rtc",
0294         .of_match_table = lpc24xx_rtc_match,
0295     },
0296 };
0297 module_platform_driver(lpc24xx_rtc_driver);
0298
0299 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>");
0300 MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs");
0301 MODULE_LICENSE("GPL");