drivers/rtc/rtc-lpc24xx.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC)
   4  *
   5  * Copyright (C) 2011 NXP Semiconductors
   6  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
   7  */
   8
   9 #include <linux/clk.h>
  10 #include <linux/io.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mod_devicetable.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/rtc.h>
  16
  17 /* LPC24xx RTC register offsets and bits */
  18 #define LPC24XX_ILR             0x00
  19 #define  LPC24XX_RTCCIF         BIT(0)
  20 #define  LPC24XX_RTCALF         BIT(1)
  21 #define LPC24XX_CTC             0x04
  22 #define LPC24XX_CCR             0x08
  23 #define  LPC24XX_CLKEN          BIT(0)
  24 #define  LPC178X_CCALEN         BIT(4)
  25 #define LPC24XX_CIIR            0x0c
  26 #define LPC24XX_AMR             0x10
  27 #define  LPC24XX_ALARM_DISABLE  0xff
  28 #define LPC24XX_CTIME0          0x14
  29 #define LPC24XX_CTIME1          0x18
  30 #define LPC24XX_CTIME2          0x1c
  31 #define LPC24XX_SEC             0x20
  32 #define LPC24XX_MIN             0x24
  33 #define LPC24XX_HOUR            0x28
  34 #define LPC24XX_DOM             0x2c
  35 #define LPC24XX_DOW             0x30
  36 #define LPC24XX_DOY             0x34
  37 #define LPC24XX_MONTH           0x38
  38 #define LPC24XX_YEAR            0x3c
  39 #define LPC24XX_ALSEC           0x60
  40 #define LPC24XX_ALMIN           0x64
  41 #define LPC24XX_ALHOUR          0x68
  42 #define LPC24XX_ALDOM           0x6c
  43 #define LPC24XX_ALDOW           0x70
  44 #define LPC24XX_ALDOY           0x74
  45 #define LPC24XX_ALMON           0x78
  46 #define LPC24XX_ALYEAR          0x7c
  47
  48 /* Macros to read fields in consolidated time (CT) registers */
  49 #define CT0_SECS(x)             (((x) >> 0)  & 0x3f)
  50 #define CT0_MINS(x)             (((x) >> 8)  & 0x3f)
  51 #define CT0_HOURS(x)            (((x) >> 16) & 0x1f)
  52 #define CT0_DOW(x)              (((x) >> 24) & 0x07)
  53 #define CT1_DOM(x)              (((x) >> 0)  & 0x1f)
  54 #define CT1_MONTH(x)            (((x) >> 8)  & 0x0f)
  55 #define CT1_YEAR(x)             (((x) >> 16) & 0xfff)
  56 #define CT2_DOY(x)              (((x) >> 0)  & 0xfff)
  57
  58 #define rtc_readl(dev, reg)             readl((dev)->rtc_base + (reg))
  59 #define rtc_writel(dev, reg, val)       writel((val), (dev)->rtc_base + (reg))
  60
  61 struct lpc24xx_rtc {
  62         void __iomem *rtc_base;
  63         struct rtc_device *rtc;
  64         struct clk *clk_rtc;
  65         struct clk *clk_reg;
  66 };
  67
  68 static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
  69 {
  70         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
  71
  72         /* Disable RTC during update */
  73         rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
  74
  75         rtc_writel(rtc, LPC24XX_SEC,    tm->tm_sec);
  76         rtc_writel(rtc, LPC24XX_MIN,    tm->tm_min);
  77         rtc_writel(rtc, LPC24XX_HOUR,   tm->tm_hour);
  78         rtc_writel(rtc, LPC24XX_DOW,    tm->tm_wday);
  79         rtc_writel(rtc, LPC24XX_DOM,    tm->tm_mday);
  80         rtc_writel(rtc, LPC24XX_DOY,    tm->tm_yday);
  81         rtc_writel(rtc, LPC24XX_MONTH,  tm->tm_mon);
  82         rtc_writel(rtc, LPC24XX_YEAR,   tm->tm_year);
  83
  84         rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
  85
  86         return 0;
  87 }
  88
  89 static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  90 {
  91         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
  92         u32 ct0, ct1, ct2;
  93
  94         ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
  95         ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
  96         ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
  97
  98         tm->tm_sec  = CT0_SECS(ct0);
  99         tm->tm_min  = CT0_MINS(ct0);
 100         tm->tm_hour = CT0_HOURS(ct0);
 101         tm->tm_wday = CT0_DOW(ct0);
 102         tm->tm_mon  = CT1_MONTH(ct1);
 103         tm->tm_mday = CT1_DOM(ct1);
 104         tm->tm_year = CT1_YEAR(ct1);
 105         tm->tm_yday = CT2_DOY(ct2);
 106
 107         return 0;
 108 }
 109
 110 static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 111 {
 112         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
 113         struct rtc_time *tm = &wkalrm->time;
 114
 115         tm->tm_sec  = rtc_readl(rtc, LPC24XX_ALSEC);
 116         tm->tm_min  = rtc_readl(rtc, LPC24XX_ALMIN);
 117         tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
 118         tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
 119         tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
 120         tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
 121         tm->tm_mon  = rtc_readl(rtc, LPC24XX_ALMON);
 122         tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
 123
 124         wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
 125         wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
 126
 127         return rtc_valid_tm(&wkalrm->time);
 128 }
 129
 130 static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 131 {
 132         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
 133         struct rtc_time *tm = &wkalrm->time;
 134
 135         /* Disable alarm irq during update */
 136         rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 137
 138         rtc_writel(rtc, LPC24XX_ALSEC,  tm->tm_sec);
 139         rtc_writel(rtc, LPC24XX_ALMIN,  tm->tm_min);
 140         rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
 141         rtc_writel(rtc, LPC24XX_ALDOM,  tm->tm_mday);
 142         rtc_writel(rtc, LPC24XX_ALDOW,  tm->tm_wday);
 143         rtc_writel(rtc, LPC24XX_ALDOY,  tm->tm_yday);
 144         rtc_writel(rtc, LPC24XX_ALMON,  tm->tm_mon);
 145         rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
 146
 147         if (wkalrm->enabled)
 148                 rtc_writel(rtc, LPC24XX_AMR, 0);
 149
 150         return 0;
 151 }
 152
 153 static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 154 {
 155         struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
 156
 157         if (enable)
 158                 rtc_writel(rtc, LPC24XX_AMR, 0);
 159         else
 160                 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 161
 162         return 0;
 163 }
 164
 165 static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data)
 166 {
 167         unsigned long events = RTC_IRQF;
 168         struct lpc24xx_rtc *rtc = data;
 169         u32 rtc_iir;
 170
 171         /* Check interrupt cause */
 172         rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
 173         if (rtc_iir & LPC24XX_RTCALF) {
 174                 events |= RTC_AF;
 175                 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 176         }
 177
 178         /* Clear interrupt status and report event */
 179         rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
 180         rtc_update_irq(rtc->rtc, 1, events);
 181
 182         return IRQ_HANDLED;
 183 }
 184
 185 static const struct rtc_class_ops lpc24xx_rtc_ops = {
 186         .read_time              = lpc24xx_rtc_read_time,
 187         .set_time               = lpc24xx_rtc_set_time,
 188         .read_alarm             = lpc24xx_rtc_read_alarm,
 189         .set_alarm              = lpc24xx_rtc_set_alarm,
 190         .alarm_irq_enable       = lpc24xx_rtc_alarm_irq_enable,
 191 };
 192
 193 static int lpc24xx_rtc_probe(struct platform_device *pdev)
 194 {
 195         struct lpc24xx_rtc *rtc;
 196         int irq, ret;
 197
 198         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 199         if (!rtc)
 200                 return -ENOMEM;
 201
 202         rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
 203         if (IS_ERR(rtc->rtc_base))
 204                 return PTR_ERR(rtc->rtc_base);
 205
 206         irq = platform_get_irq(pdev, 0);
 207         if (irq < 0)
 208                 return irq;
 209
 210         rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
 211         if (IS_ERR(rtc->clk_rtc)) {
 212                 dev_err(&pdev->dev, "error getting rtc clock\n");
 213                 return PTR_ERR(rtc->clk_rtc);
 214         }
 215
 216         rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
 217         if (IS_ERR(rtc->clk_reg)) {
 218                 dev_err(&pdev->dev, "error getting reg clock\n");
 219                 return PTR_ERR(rtc->clk_reg);
 220         }
 221
 222         ret = clk_prepare_enable(rtc->clk_rtc);
 223         if (ret) {
 224                 dev_err(&pdev->dev, "unable to enable rtc clock\n");
 225                 return ret;
 226         }
 227
 228         ret = clk_prepare_enable(rtc->clk_reg);
 229         if (ret) {
 230                 dev_err(&pdev->dev, "unable to enable reg clock\n");
 231                 goto disable_rtc_clk;
 232         }
 233
 234         platform_set_drvdata(pdev, rtc);
 235
 236         /* Clear any pending interrupts */
 237         rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF);
 238
 239         /* Enable RTC count */
 240         rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN);
 241
 242         ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
 243                                pdev->name, rtc);
 244         if (ret < 0) {
 245                 dev_warn(&pdev->dev, "can't request interrupt\n");
 246                 goto disable_clks;
 247         }
 248
 249         rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc",
 250                                             &lpc24xx_rtc_ops, THIS_MODULE);
 251         if (IS_ERR(rtc->rtc)) {
 252                 dev_err(&pdev->dev, "can't register rtc device\n");
 253                 ret = PTR_ERR(rtc->rtc);
 254                 goto disable_clks;
 255         }
 256
 257         return 0;
 258
 259 disable_clks:
 260         clk_disable_unprepare(rtc->clk_reg);
 261 disable_rtc_clk:
 262         clk_disable_unprepare(rtc->clk_rtc);
 263         return ret;
 264 }
 265
 266 static void lpc24xx_rtc_remove(struct platform_device *pdev)
 267 {
 268         struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
 269
 270         /* Ensure all interrupt sources are masked */
 271         rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
 272         rtc_writel(rtc, LPC24XX_CIIR, 0);
 273
 274         rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN);
 275
 276         clk_disable_unprepare(rtc->clk_rtc);
 277         clk_disable_unprepare(rtc->clk_reg);
 278 }
 279
 280 static const struct of_device_id lpc24xx_rtc_match[] = {
 281         { .compatible = "nxp,lpc1788-rtc" },
 282         { }
 283 };
 284 MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
 285
 286 static struct platform_driver lpc24xx_rtc_driver = {
 287         .probe  = lpc24xx_rtc_probe,
 288         .remove = lpc24xx_rtc_remove,
 289         .driver = {
 290                 .name = "lpc24xx-rtc",
 291                 .of_match_table = lpc24xx_rtc_match,
 292         },
 293 };
 294 module_platform_driver(lpc24xx_rtc_driver);
 295
 296 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>");
 297 MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs");
 298 MODULE_LICENSE("GPL");