drivers/rtc/rtc-zynqmp.c

   1 /*
   2  * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver
   3  *
   4  * Copyright (C) 2015 Xilinx, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program. If not, see <http://www.gnu.org/licenses/>.
  17  *
  18  */
  19
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22 #include <linux/io.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/rtc.h>
  27
  28 /* RTC Registers */
  29 #define RTC_SET_TM_WR           0x00
  30 #define RTC_SET_TM_RD           0x04
  31 #define RTC_CALIB_WR            0x08
  32 #define RTC_CALIB_RD            0x0C
  33 #define RTC_CUR_TM              0x10
  34 #define RTC_CUR_TICK            0x14
  35 #define RTC_ALRM                0x18
  36 #define RTC_INT_STS             0x20
  37 #define RTC_INT_MASK            0x24
  38 #define RTC_INT_EN              0x28
  39 #define RTC_INT_DIS             0x2C
  40 #define RTC_CTRL                0x40
  41
  42 #define RTC_FR_EN               BIT(20)
  43 #define RTC_FR_DATSHIFT         16
  44 #define RTC_TICK_MASK           0xFFFF
  45 #define RTC_INT_SEC             BIT(0)
  46 #define RTC_INT_ALRM            BIT(1)
  47 #define RTC_OSC_EN              BIT(24)
  48
  49 #define RTC_CALIB_DEF           0x198233
  50 #define RTC_CALIB_MASK          0x1FFFFF
  51 #define RTC_SEC_MAX_VAL         0xFFFFFFFF
  52
  53 struct xlnx_rtc_dev {
  54         struct rtc_device       *rtc;
  55         void __iomem            *reg_base;
  56         int                     alarm_irq;
  57         int                     sec_irq;
  58 };
  59
  60 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
  61 {
  62         struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
  63         unsigned long new_time;
  64
  65         new_time = rtc_tm_to_time64(tm);
  66
  67         if (new_time > RTC_SEC_MAX_VAL)
  68                 return -EINVAL;
  69
  70         writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
  71
  72         return 0;
  73 }
  74
  75 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  76 {
  77         struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
  78
  79         rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm);
  80
  81         return rtc_valid_tm(tm);
  82 }
  83
  84 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  85 {
  86         struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
  87
  88         rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time);
  89         alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM;
  90
  91         return 0;
  92 }
  93
  94 static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
  95 {
  96         struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
  97
  98         if (enabled)
  99                 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
 100         else
 101                 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
 102
 103         return 0;
 104 }
 105
 106 static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 107 {
 108         struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
 109         unsigned long alarm_time;
 110
 111         alarm_time = rtc_tm_to_time64(&alrm->time);
 112
 113         if (alarm_time > RTC_SEC_MAX_VAL)
 114                 return -EINVAL;
 115
 116         writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM));
 117
 118         xlnx_rtc_alarm_irq_enable(dev, alrm->enabled);
 119
 120         return 0;
 121 }
 122
 123 static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev, u32 calibval)
 124 {
 125         /*
 126          * Based on crystal freq of 33.330 KHz
 127          * set the seconds counter and enable, set fractions counter
 128          * to default value suggested as per design spec
 129          * to correct RTC delay in frequency over period of time.
 130          */
 131         calibval &= RTC_CALIB_MASK;
 132         writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
 133 }
 134
 135 static const struct rtc_class_ops xlnx_rtc_ops = {
 136         .set_time         = xlnx_rtc_set_time,
 137         .read_time        = xlnx_rtc_read_time,
 138         .read_alarm       = xlnx_rtc_read_alarm,
 139         .set_alarm        = xlnx_rtc_set_alarm,
 140         .alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
 141 };
 142
 143 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
 144 {
 145         struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id;
 146         unsigned int status;
 147
 148         status = readl(xrtcdev->reg_base + RTC_INT_STS);
 149         /* Check if interrupt asserted */
 150         if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
 151                 return IRQ_NONE;
 152
 153         /* Clear interrupt */
 154         writel(status, xrtcdev->reg_base + RTC_INT_STS);
 155
 156         if (status & RTC_INT_SEC)
 157                 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_UF);
 158         if (status & RTC_INT_ALRM)
 159                 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
 160
 161         return IRQ_HANDLED;
 162 }
 163
 164 static int xlnx_rtc_probe(struct platform_device *pdev)
 165 {
 166         struct xlnx_rtc_dev *xrtcdev;
 167         struct resource *res;
 168         int ret;
 169         unsigned int calibvalue;
 170
 171         xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
 172         if (!xrtcdev)
 173                 return -ENOMEM;
 174
 175         platform_set_drvdata(pdev, xrtcdev);
 176
 177         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 178
 179         xrtcdev->reg_base = devm_ioremap_resource(&pdev->dev, res);
 180         if (IS_ERR(xrtcdev->reg_base))
 181                 return PTR_ERR(xrtcdev->reg_base);
 182
 183         xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm");
 184         if (xrtcdev->alarm_irq < 0) {
 185                 dev_err(&pdev->dev, "no irq resource\n");
 186                 return xrtcdev->alarm_irq;
 187         }
 188         ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq,
 189                                xlnx_rtc_interrupt, 0,
 190                                dev_name(&pdev->dev), xrtcdev);
 191         if (ret) {
 192                 dev_err(&pdev->dev, "request irq failed\n");
 193                 return ret;
 194         }
 195
 196         xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec");
 197         if (xrtcdev->sec_irq < 0) {
 198                 dev_err(&pdev->dev, "no irq resource\n");
 199                 return xrtcdev->sec_irq;
 200         }
 201         ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq,
 202                                xlnx_rtc_interrupt, 0,
 203                                dev_name(&pdev->dev), xrtcdev);
 204         if (ret) {
 205                 dev_err(&pdev->dev, "request irq failed\n");
 206                 return ret;
 207         }
 208
 209         ret = of_property_read_u32(pdev->dev.of_node, "calibration",
 210                                    &calibvalue);
 211         if (ret)
 212                 calibvalue = RTC_CALIB_DEF;
 213
 214         xlnx_init_rtc(xrtcdev, calibvalue);
 215
 216         device_init_wakeup(&pdev->dev, 1);
 217
 218         xrtcdev->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 219                                          &xlnx_rtc_ops, THIS_MODULE);
 220         return PTR_ERR_OR_ZERO(xrtcdev->rtc);
 221 }
 222
 223 static int xlnx_rtc_remove(struct platform_device *pdev)
 224 {
 225         xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
 226         device_init_wakeup(&pdev->dev, 0);
 227
 228         return 0;
 229 }
 230
 231 static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
 232 {
 233         struct platform_device *pdev = to_platform_device(dev);
 234         struct xlnx_rtc_dev *xrtcdev = platform_get_drvdata(pdev);
 235
 236         if (device_may_wakeup(&pdev->dev))
 237                 enable_irq_wake(xrtcdev->alarm_irq);
 238         else
 239                 xlnx_rtc_alarm_irq_enable(dev, 0);
 240
 241         return 0;
 242 }
 243
 244 static int __maybe_unused xlnx_rtc_resume(struct device *dev)
 245 {
 246         struct platform_device *pdev = to_platform_device(dev);
 247         struct xlnx_rtc_dev *xrtcdev = platform_get_drvdata(pdev);
 248
 249         if (device_may_wakeup(&pdev->dev))
 250                 disable_irq_wake(xrtcdev->alarm_irq);
 251         else
 252                 xlnx_rtc_alarm_irq_enable(dev, 1);
 253
 254         return 0;
 255 }
 256
 257 static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume);
 258
 259 static const struct of_device_id xlnx_rtc_of_match[] = {
 260         {.compatible = "xlnx,zynqmp-rtc" },
 261         { }
 262 };
 263 MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match);
 264
 265 static struct platform_driver xlnx_rtc_driver = {
 266         .probe          = xlnx_rtc_probe,
 267         .remove         = xlnx_rtc_remove,
 268         .driver         = {
 269                 .name   = KBUILD_MODNAME,
 270                 .pm     = &xlnx_rtc_pm_ops,
 271                 .of_match_table = xlnx_rtc_of_match,
 272         },
 273 };
 274
 275 module_platform_driver(xlnx_rtc_driver);
 276
 277 MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
 278 MODULE_AUTHOR("Xilinx Inc.");
 279 MODULE_LICENSE("GPL v2");