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         spin_lock_irq(&rtc->lock);
  98         rtc_time_to_tm(rtc->alarm_time, &alrm->time);
  99         alrm->enabled = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
 100         alrm->pending = rtc_readl(rtc, ISR) & RTC_BIT(ISR_TOPI) ? 1 : 0;
 101         spin_unlock_irq(&rtc->lock);
 102
 103         return 0;
 104 }
 105
 106 static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 107 {
 108         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
 109         unsigned long rtc_unix_time;
 110         unsigned long alarm_unix_time;
 111         int ret;
 112
 113         rtc_unix_time = rtc_readl(rtc, VAL);
 114
 115         ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
 116         if (ret)
 117                 return ret;
 118
 119         if (alarm_unix_time < rtc_unix_time)
 120                 return -EINVAL;
 121
 122         spin_lock_irq(&rtc->lock);
 123         rtc->alarm_time = alarm_unix_time;
 124         rtc_writel(rtc, TOP, rtc->alarm_time);
 125         if (alrm->enabled)
 126                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 127                                 | RTC_BIT(CTRL_TOPEN));
 128         else
 129                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 130                                 & ~RTC_BIT(CTRL_TOPEN));
 131         spin_unlock_irq(&rtc->lock);
 132
 133         return ret;
 134 }
 135
 136 static int at32_rtc_ioctl(struct device *dev, unsigned int cmd,
 137                         unsigned long arg)
 138 {
 139         struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
 140         int ret = 0;
 141
 142         spin_lock_irq(&rtc->lock);
 143
 144         switch (cmd) {
 145         case RTC_AIE_ON:
 146                 if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
 147                         ret = -EINVAL;
 148                         break;
 149                 }
 150                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 151                                 | RTC_BIT(CTRL_TOPEN));
 152                 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
 153                 rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
 154                 break;
 155         case RTC_AIE_OFF:
 156                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 157                                 & ~RTC_BIT(CTRL_TOPEN));
 158                 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
 159                 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
 160                 break;
 161         default:
 162                 ret = -ENOIOCTLCMD;
 163                 break;
 164         }
 165
 166         spin_unlock_irq(&rtc->lock);
 167
 168         return ret;
 169 }
 170
 171 static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
 172 {
 173         struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
 174         unsigned long isr = rtc_readl(rtc, ISR);
 175         unsigned long events = 0;
 176         int ret = IRQ_NONE;
 177
 178         spin_lock(&rtc->lock);
 179
 180         if (isr & RTC_BIT(ISR_TOPI)) {
 181                 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
 182                 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
 183                 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
 184                                 & ~RTC_BIT(CTRL_TOPEN));
 185                 rtc_writel(rtc, VAL, rtc->alarm_time);
 186                 events = RTC_AF | RTC_IRQF;
 187                 rtc_update_irq(rtc->rtc, 1, events);
 188                 ret = IRQ_HANDLED;
 189         }
 190
 191         spin_unlock(&rtc->lock);
 192
 193         return ret;
 194 }
 195
 196 static struct rtc_class_ops at32_rtc_ops = {
 197         .ioctl          = at32_rtc_ioctl,
 198         .read_time      = at32_rtc_readtime,
 199         .set_time       = at32_rtc_settime,
 200         .read_alarm     = at32_rtc_readalarm,
 201         .set_alarm      = at32_rtc_setalarm,
 202 };
 203
 204 static int __init at32_rtc_probe(struct platform_device *pdev)
 205 {
 206         struct resource *regs;
 207         struct rtc_at32ap700x *rtc;
 208         int irq = -1;
 209         int ret;
 210
 211         rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
 212         if (!rtc) {
 213                 dev_dbg(&pdev->dev, "out of memory\n");
 214                 return -ENOMEM;
 215         }
 216
 217         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 218         if (!regs) {
 219                 dev_dbg(&pdev->dev, "no mmio resource defined\n");
 220                 ret = -ENXIO;
 221                 goto out;
 222         }
 223
 224         irq = platform_get_irq(pdev, 0);
 225         if (irq < 0) {
 226                 dev_dbg(&pdev->dev, "could not get irq\n");
 227                 ret = -ENXIO;
 228                 goto out;
 229         }
 230
 231         rtc->irq = irq;
 232         rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);
 233         if (!rtc->regs) {
 234                 ret = -ENOMEM;
 235                 dev_dbg(&pdev->dev, "could not map I/O memory\n");
 236                 goto out;
 237         }
 238         spin_lock_init(&rtc->lock);
 239
 240         /*
 241          * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
 242          *
 243          * Do not reset VAL register, as it can hold an old time
 244          * from last JTAG reset.
 245          */
 246         if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
 247                 rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
 248                 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
 249                 rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
 250                                 | RTC_BIT(CTRL_EN));
 251         }
 252
 253         ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
 254         if (ret) {
 255                 dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
 256                 goto out_iounmap;
 257         }
 258
 259         rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
 260                                 &at32_rtc_ops, THIS_MODULE);
 261         if (IS_ERR(rtc->rtc)) {
 262                 dev_dbg(&pdev->dev, "could not register rtc device\n");
 263                 ret = PTR_ERR(rtc->rtc);
 264                 goto out_free_irq;
 265         }
 266
 267         platform_set_drvdata(pdev, rtc);
 268
 269         dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
 270                         (unsigned long)rtc->regs, rtc->irq);
 271
 272         return 0;
 273
 274 out_free_irq:
 275         free_irq(irq, rtc);
 276 out_iounmap:
 277         iounmap(rtc->regs);
 278 out:
 279         kfree(rtc);
 280         return ret;
 281 }
 282
 283 static int __exit at32_rtc_remove(struct platform_device *pdev)
 284 {
 285         struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
 286
 287         free_irq(rtc->irq, rtc);
 288         iounmap(rtc->regs);
 289         rtc_device_unregister(rtc->rtc);
 290         kfree(rtc);
 291         platform_set_drvdata(pdev, NULL);
 292
 293         return 0;
 294 }
 295
 296 MODULE_ALIAS("platform:at32ap700x_rtc");
 297
 298 static struct platform_driver at32_rtc_driver = {
 299         .remove         = __exit_p(at32_rtc_remove),
 300         .driver         = {
 301                 .name   = "at32ap700x_rtc",
 302                 .owner  = THIS_MODULE,
 303         },
 304 };
 305
 306 static int __init at32_rtc_init(void)
 307 {
 308         return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
 309 }
 310 module_init(at32_rtc_init);
 311
 312 static void __exit at32_rtc_exit(void)
 313 {
 314         platform_driver_unregister(&at32_rtc_driver);
 315 }
 316 module_exit(at32_rtc_exit);
 317
 318 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
 319 MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
 320 MODULE_LICENSE("GPL");