drivers/rtc/rtc-at32ap700x.c

   1 /*
   2  * An RTC driver for the AVR32 AT32AP700x processor series.
   3  *
   4  * Copyright (C) 2007 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/rtc.h>
  15 #include <linux/io.h>
  16
  17 /*
  18  * This is a bare-bones RTC. It runs during most system sleep states, but has
  19  * no battery backup and gets reset during system restart.  It must be
  20  * initialized from an external clock (network, I2C, etc) before it can be of
  21  * much use.
  22  *
  23  * The alarm functionality is limited by the hardware, not supporting
  24  * periodic interrupts.
  25  */
  26
  27 #define RTC_CTRL                0x00
  28 #define RTC_CTRL_EN                0
  29 #define RTC_CTRL_PCLR              1
  30 #define RTC_CTRL_TOPEN             2
  31 #define RTC_CTRL_PSEL              8
  32
  33 #define RTC_VAL                 0x04
  34
  35 #define RTC_TOP                 0x08
  36
  37 #define RTC_IER                 0x10
  38 #define RTC_IER_TOPI               0
  39
  40 #define RTC_IDR                 0x14
  41 #define RTC_IDR_TOPI               0
  42
  43 #define RTC_IMR                 0x18
  44 #define RTC_IMR_TOPI               0
  45
  46 #define RTC_ISR                 0x1c
  47 #define RTC_ISR_TOPI               0
  48
  49 #define RTC_ICR                 0x20
  50 #define RTC_ICR_TOPI               0
  51
  52 #define RTC_BIT(name)           (1 << RTC_##name)
  53 #define RTC_BF(name, value)     ((value) << RTC_##name)
  54
  55 #define rtc_readl(dev, reg)                             \
  56         __raw_readl((dev)->regs + RTC_##reg)
  57 #define rtc_writel(dev, reg, value)                     \
  58         __raw_writel((value), (dev)->regs + RTC_##reg)
  59
  60 struct rtc_at32ap700x {
  61         struct rtc_device       *rtc;
  62         void __iomem            *regs;
  63         unsigned long           alarm_time;
  64         unsigned long           irq;
  65         /* Protect against concurrent register access. */
  66         spinlock_t              lock;
  67 };
  68
  69 static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
  70 {
  71         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
  72         unsigned long now;
  73
  74         now = rtc_readl(rtc, VAL);
  75         rtc_time_to_tm(now, tm);
  76
  77         return 0;
  78 }
  79
  80 static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
  81 {
  82         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
  83         unsigned long now;
  84         int ret;
  85
  86         ret = rtc_tm_to_time(tm, &now);
  87         if (ret == 0)
  88                 rtc_writel(rtc, VAL, now);
  89
  90         return ret;
  91 }
  92
  93 static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
  94 {
  95         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
  96
  97         rtc_time_to_tm(rtc->alarm_time, &alrm->time);
  98         alrm->pending = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
  99
 100         return 0;
 101 }
 102
 103 static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 104 {
 105         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
 106         unsigned long rtc_unix_time;
 107         unsigned long alarm_unix_time;
 108         int ret;
 109
 110         rtc_unix_time = rtc_readl(rtc, VAL);
 111
 112         ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
 113         if (ret)
 114                 return ret;
 115
 116         if (alarm_unix_time < rtc_unix_time)
 117                 return -EINVAL;
 118
 119         spin_lock_irq(&rtc->lock);
 120         rtc->alarm_time = alarm_unix_time;
 121         rtc_writel(rtc, TOP, rtc->alarm_time);
 122         if (alrm->pending)
 123                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 124                                 | RTC_BIT(CTRL_TOPEN));
 125         else
 126                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 127                                 & ~RTC_BIT(CTRL_TOPEN));
 128         spin_unlock_irq(&rtc->lock);
 129
 130         return ret;
 131 }
 132
 133 static int at32_rtc_ioctl(struct device *dev, unsigned int cmd,
 134                         unsigned long arg)
 135 {
 136         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
 137         int ret = 0;
 138
 139         spin_lock_irq(&rtc->lock);
 140
 141         switch (cmd) {
 142         case RTC_AIE_ON:
 143                 if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
 144                         ret = -EINVAL;
 145                         break;
 146                 }
 147                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 148                                 | RTC_BIT(CTRL_TOPEN));
 149                 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
 150                 rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
 151                 break;
 152         case RTC_AIE_OFF:
 153                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 154                                 & ~RTC_BIT(CTRL_TOPEN));
 155                 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
 156                 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
 157                 break;
 158         default:
 159                 ret = -ENOIOCTLCMD;
 160                 break;
 161         }
 162
 163         spin_unlock_irq(&rtc->lock);
 164
 165         return ret;
 166 }
 167
 168 static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
 169 {
 170         struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
 171         unsigned long isr = rtc_readl(rtc, ISR);
 172         unsigned long events = 0;
 173         int ret = IRQ_NONE;
 174
 175         spin_lock(&rtc->lock);
 176
 177         if (isr & RTC_BIT(ISR_TOPI)) {
 178                 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
 179                 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
 180                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 181                                 & ~RTC_BIT(CTRL_TOPEN));
 182                 rtc_writel(rtc, VAL, rtc->alarm_time);
 183                 events = RTC_AF | RTC_IRQF;
 184                 rtc_update_irq(rtc->rtc, 1, events);
 185                 ret = IRQ_HANDLED;
 186         }
 187
 188         spin_unlock(&rtc->lock);
 189
 190         return ret;
 191 }
 192
 193 static struct rtc_class_ops at32_rtc_ops = {
 194         .ioctl          = at32_rtc_ioctl,
 195         .read_time      = at32_rtc_readtime,
 196         .set_time       = at32_rtc_settime,
 197         .read_alarm     = at32_rtc_readalarm,
 198         .set_alarm      = at32_rtc_setalarm,
 199 };
 200
 201 static int __init at32_rtc_probe(struct platform_device *pdev)
 202 {
 203         struct resource *regs;
 204         struct rtc_at32ap700x *rtc;
 205         int irq = -1;
 206         int ret;
 207
 208         rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
 209         if (!rtc) {
 210                 dev_dbg(&pdev->dev, "out of memory\n");
 211                 return -ENOMEM;
 212         }
 213
 214         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 215         if (!regs) {
 216                 dev_dbg(&pdev->dev, "no mmio resource defined\n");
 217                 ret = -ENXIO;
 218                 goto out;
 219         }
 220
 221         irq = platform_get_irq(pdev, 0);
 222         if (irq < 0) {
 223                 dev_dbg(&pdev->dev, "could not get irq\n");
 224                 ret = -ENXIO;
 225                 goto out;
 226         }
 227
 228         rtc->irq = irq;
 229         rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);
 230         if (!rtc->regs) {
 231                 ret = -ENOMEM;
 232                 dev_dbg(&pdev->dev, "could not map I/O memory\n");
 233                 goto out;
 234         }
 235         spin_lock_init(&rtc->lock);
 236
 237         /*
 238          * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
 239          *
 240          * Do not reset VAL register, as it can hold an old time
 241          * from last JTAG reset.
 242          */
 243         if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
 244                 rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
 245                 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
 246                 rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
 247                                 | RTC_BIT(CTRL_EN));
 248         }
 249
 250         ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
 251         if (ret) {
 252                 dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
 253                 goto out_iounmap;
 254         }
 255
 256         rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
 257                                 &at32_rtc_ops, THIS_MODULE);
 258         if (IS_ERR(rtc->rtc)) {
 259                 dev_dbg(&pdev->dev, "could not register rtc device\n");
 260                 ret = PTR_ERR(rtc->rtc);
 261                 goto out_free_irq;
 262         }
 263
 264         platform_set_drvdata(pdev, rtc);
 265
 266         dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
 267                         (unsigned long)rtc->regs, rtc->irq);
 268
 269         return 0;
 270
 271 out_free_irq:
 272         free_irq(irq, rtc);
 273 out_iounmap:
 274         iounmap(rtc->regs);
 275 out:
 276         kfree(rtc);
 277         return ret;
 278 }
 279
 280 static int __exit at32_rtc_remove(struct platform_device *pdev)
 281 {
 282         struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
 283
 284         free_irq(rtc->irq, rtc);
 285         iounmap(rtc->regs);
 286         rtc_device_unregister(rtc->rtc);
 287         kfree(rtc);
 288         platform_set_drvdata(pdev, NULL);
 289
 290         return 0;
 291 }
 292
 293 MODULE_ALIAS("platform:at32ap700x_rtc");
 294
 295 static struct platform_driver at32_rtc_driver = {
 296         .remove         = __exit_p(at32_rtc_remove),
 297         .driver         = {
 298                 .name   = "at32ap700x_rtc",
 299                 .owner  = THIS_MODULE,
 300         },
 301 };
 302
 303 static int __init at32_rtc_init(void)
 304 {
 305         return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
 306 }
 307 module_init(at32_rtc_init);
 308
 309 static void __exit at32_rtc_exit(void)
 310 {
 311         platform_driver_unregister(&at32_rtc_driver);
 312 }
 313 module_exit(at32_rtc_exit);
 314
 315 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
 316 MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
 317 MODULE_LICENSE("GPL");