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