drivers/rtc/rtc-lpc24xx.c

   1 /*
   2  * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC)
   3  *
   4  * Copyright (C) 2011 NXP Semiconductors
   5  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  */
  13
  14 #include <linux/clk.h>
  15 #include <linux/io.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/of_device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/rtc.h>
  22
  23 /* LPC24xx RTC register offsets and bits */
  24 #define LPC24XX_ILR             0x00
  25 #define  LPC24XX_RTCCIF         BIT(0)
  26 #define  LPC24XX_RTCALF         BIT(1)
  27 #define LPC24XX_CTC             0x04
  28 #define LPC24XX_CCR             0x08
  29 #define  LPC24XX_CLKEN          BIT(0)
  30 #define  LPC178X_CCALEN         BIT(4)
  31 #define LPC24XX_CIIR            0x0c
  32 #define LPC24XX_AMR             0x10
  33 #define  LPC24XX_ALARM_DISABLE  0xff
  34 #define LPC24XX_CTIME0          0x14
  35 #define LPC24XX_CTIME1          0x18
  36 #define LPC24XX_CTIME2          0x1c
  37 #define LPC24XX_SEC             0x20
  38 #define LPC24XX_MIN             0x24
  39 #define LPC24XX_HOUR            0x28
  40 #define LPC24XX_DOM             0x2c
  41 #define LPC24XX_DOW             0x30
  42 #define LPC24XX_DOY             0x34
  43 #define LPC24XX_MONTH           0x38
  44 #define LPC24XX_YEAR            0x3c
  45 #define LPC24XX_ALSEC           0x60
  46 #define LPC24XX_ALMIN           0x64
  47 #define LPC24XX_ALHOUR          0x68
  48 #define LPC24XX_ALDOM           0x6c
  49 #define LPC24XX_ALDOW           0x70
  50 #define LPC24XX_ALDOY           0x74
  51 #define LPC24XX_ALMON           0x78
  52 #define LPC24XX_ALYEAR          0x7c
  53
  54 /* Macros to read fields in consolidated time (CT) registers */
  55 #define CT0_SECS(x)             (((x) >> 0)  & 0x3f)
  56 #define CT0_MINS(x)             (((x) >> 8)  & 0x3f)
  57 #define CT0_HOURS(x)            (((x) >> 16) & 0x1f)
  58 #define CT0_DOW(x)              (((x) >> 24) & 0x07)
  59 #define CT1_DOM(x)              (((x) >> 0)  & 0x1f)
  60 #define CT1_MONTH(x)            (((x) >> 8)  & 0x0f)
  61 #define CT1_YEAR(x)             (((x) >> 16) & 0xfff)
  62 #define CT2_DOY(x)              (((x) >> 0)  & 0xfff)
  63
  64 #define rtc_readl(dev, reg)             readl((dev)->rtc_base + (reg))
  65 #define rtc_writel(dev, reg, val)       writel((val), (dev)->rtc_base + (reg))
  66
  67 struct lpc24xx_rtc {
  68         void __iomem *rtc_base;
  69         struct rtc_device *rtc;
  70         struct clk *clk_rtc;
  71         struct clk *clk_reg;
  72 };
  73
  74 static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
  75 {
  76         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
  77
  78         /* Disable RTC during update */
  79         rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
  80
  81         rtc_writel(rtc, LPC24XX_SEC,    tm->tm_sec);
  82         rtc_writel(rtc, LPC24XX_MIN,    tm->tm_min);
  83         rtc_writel(rtc, LPC24XX_HOUR,   tm->tm_hour);
  84         rtc_writel(rtc, LPC24XX_DOW,    tm->tm_wday);
  85         rtc_writel(rtc, LPC24XX_DOM,    tm->tm_mday);
  86         rtc_writel(rtc, LPC24XX_DOY,    tm->tm_yday);
  87         rtc_writel(rtc, LPC24XX_MONTH,  tm->tm_mon);
  88         rtc_writel(rtc, LPC24XX_YEAR,   tm->tm_year);
  89
  90         rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
  91
  92         return 0;
  93 }
  94
  95 static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  96 {
  97         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
  98         u32 ct0, ct1, ct2;
  99
 100         ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
 101         ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
 102         ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
 103
 104         tm->tm_sec  = CT0_SECS(ct0);
 105         tm->tm_min  = CT0_MINS(ct0);
 106         tm->tm_hour = CT0_HOURS(ct0);
 107         tm->tm_wday = CT0_DOW(ct0);
 108         tm->tm_mon  = CT1_MONTH(ct1);
 109         tm->tm_mday = CT1_DOM(ct1);
 110         tm->tm_year = CT1_YEAR(ct1);
 111         tm->tm_yday = CT2_DOY(ct2);
 112
 113         return 0;
 114 }
 115
 116 static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 117 {
 118         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
 119         struct rtc_time *tm = &wkalrm->time;
 120
 121         tm->tm_sec  = rtc_readl(rtc, LPC24XX_ALSEC);
 122         tm->tm_min  = rtc_readl(rtc, LPC24XX_ALMIN);
 123         tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
 124         tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
 125         tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
 126         tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
 127         tm->tm_mon  = rtc_readl(rtc, LPC24XX_ALMON);
 128         tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
 129
 130         wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
 131         wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
 132
 133         return rtc_valid_tm(&wkalrm->time);
 134 }
 135
 136 static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 137 {
 138         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
 139         struct rtc_time *tm = &wkalrm->time;
 140
 141         /* Disable alarm irq during update */
 142         rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 143
 144         rtc_writel(rtc, LPC24XX_ALSEC,  tm->tm_sec);
 145         rtc_writel(rtc, LPC24XX_ALMIN,  tm->tm_min);
 146         rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
 147         rtc_writel(rtc, LPC24XX_ALDOM,  tm->tm_mday);
 148         rtc_writel(rtc, LPC24XX_ALDOW,  tm->tm_wday);
 149         rtc_writel(rtc, LPC24XX_ALDOY,  tm->tm_yday);
 150         rtc_writel(rtc, LPC24XX_ALMON,  tm->tm_mon);
 151         rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
 152
 153         if (wkalrm->enabled)
 154                 rtc_writel(rtc, LPC24XX_AMR, 0);
 155
 156         return 0;
 157 }
 158
 159 static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 160 {
 161         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
 162
 163         if (enable)
 164                 rtc_writel(rtc, LPC24XX_AMR, 0);
 165         else
 166                 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 167
 168         return 0;
 169 }
 170
 171 static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data)
 172 {
 173         unsigned long events = RTC_IRQF;
 174         struct lpc24xx_rtc *rtc = data;
 175         u32 rtc_iir;
 176
 177         /* Check interrupt cause */
 178         rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
 179         if (rtc_iir & LPC24XX_RTCALF) {
 180                 events |= RTC_AF;
 181                 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 182         }
 183
 184         /* Clear interrupt status and report event */
 185         rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
 186         rtc_update_irq(rtc->rtc, 1, events);
 187
 188         return IRQ_HANDLED;
 189 }
 190
 191 static const struct rtc_class_ops lpc24xx_rtc_ops = {
 192         .read_time              = lpc24xx_rtc_read_time,
 193         .set_time               = lpc24xx_rtc_set_time,
 194         .read_alarm             = lpc24xx_rtc_read_alarm,
 195         .set_alarm              = lpc24xx_rtc_set_alarm,
 196         .alarm_irq_enable       = lpc24xx_rtc_alarm_irq_enable,
 197 };
 198
 199 static int lpc24xx_rtc_probe(struct platform_device *pdev)
 200 {
 201         struct lpc24xx_rtc *rtc;
 202         struct resource *res;
 203         int irq, ret;
 204
 205         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 206         if (!rtc)
 207                 return -ENOMEM;
 208
 209         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 210         rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res);
 211         if (IS_ERR(rtc->rtc_base))
 212                 return PTR_ERR(rtc->rtc_base);
 213
 214         irq = platform_get_irq(pdev, 0);
 215         if (irq < 0) {
 216                 dev_warn(&pdev->dev, "can't get interrupt resource\n");
 217                 return irq;
 218         }
 219
 220         rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
 221         if (IS_ERR(rtc->clk_rtc)) {
 222                 dev_err(&pdev->dev, "error getting rtc clock\n");
 223                 return PTR_ERR(rtc->clk_rtc);
 224         }
 225
 226         rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
 227         if (IS_ERR(rtc->clk_reg)) {
 228                 dev_err(&pdev->dev, "error getting reg clock\n");
 229                 return PTR_ERR(rtc->clk_reg);
 230         }
 231
 232         ret = clk_prepare_enable(rtc->clk_rtc);
 233         if (ret) {
 234                 dev_err(&pdev->dev, "unable to enable rtc clock\n");
 235                 return ret;
 236         }
 237
 238         ret = clk_prepare_enable(rtc->clk_reg);
 239         if (ret) {
 240                 dev_err(&pdev->dev, "unable to enable reg clock\n");
 241                 goto disable_rtc_clk;
 242         }
 243
 244         platform_set_drvdata(pdev, rtc);
 245
 246         /* Clear any pending interrupts */
 247         rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF);
 248
 249         /* Enable RTC count */
 250         rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
 251
 252         ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
 253                                pdev->name, rtc);
 254         if (ret < 0) {
 255                 dev_warn(&pdev->dev, "can't request interrupt\n");
 256                 goto disable_clks;
 257         }
 258
 259         rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc",
 260                                             &lpc24xx_rtc_ops, THIS_MODULE);
 261         if (IS_ERR(rtc->rtc)) {
 262                 dev_err(&pdev->dev, "can't register rtc device\n");
 263                 ret = PTR_ERR(rtc->rtc);
 264                 goto disable_clks;
 265         }
 266
 267         return 0;
 268
 269 disable_clks:
 270         clk_disable_unprepare(rtc->clk_reg);
 271 disable_rtc_clk:
 272         clk_disable_unprepare(rtc->clk_rtc);
 273         return ret;
 274 }
 275
 276 static int lpc24xx_rtc_remove(struct platform_device *pdev)
 277 {
 278         struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
 279
 280         /* Ensure all interrupt sources are masked */
 281         rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 282         rtc_writel(rtc, LPC24XX_CIIR, 0);
 283
 284         rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
 285
 286         clk_disable_unprepare(rtc->clk_rtc);
 287         clk_disable_unprepare(rtc->clk_reg);
 288
 289         return 0;
 290 }
 291
 292 static const struct of_device_id lpc24xx_rtc_match[] = {
 293         { .compatible = "nxp,lpc1788-rtc" },
 294         { }
 295 };
 296 MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
 297
 298 static struct platform_driver lpc24xx_rtc_driver = {
 299         .probe  = lpc24xx_rtc_probe,
 300         .remove = lpc24xx_rtc_remove,
 301         .driver = {
 302                 .name = "lpc24xx-rtc",
 303                 .of_match_table = lpc24xx_rtc_match,
 304         },
 305 };
 306 module_platform_driver(lpc24xx_rtc_driver);
 307
 308 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>");
 309 MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs");
 310 MODULE_LICENSE("GPL");