drivers/rtc/rtc-stmp3xxx.c

   1 /*
   2  * Freescale STMP37XX/STMP378X Real Time Clock driver
   3  *
   4  * Copyright (c) 2007 Sigmatel, Inc.
   5  * Peter Hartley, <peter.hartley@sigmatel.com>
   6  *
   7  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
   8  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
   9  */
  10
  11 /*
  12  * The code contained herein is licensed under the GNU General Public
  13  * License. You may obtain a copy of the GNU General Public License
  14  * Version 2 or later at the following locations:
  15  *
  16  * http://www.opensource.org/licenses/gpl-license.html
  17  * http://www.gnu.org/copyleft/gpl.html
  18  */
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/rtc.h>
  25 #include <linux/slab.h>
  26
  27 #include <mach/platform.h>
  28 #include <mach/stmp3xxx.h>
  29 #include <mach/regs-rtc.h>
  30
  31 struct stmp3xxx_rtc_data {
  32         struct rtc_device *rtc;
  33         unsigned irq_count;
  34         void __iomem *io;
  35         int irq_alarm, irq_1msec;
  36 };
  37
  38 static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
  39 {
  40         /*
  41          * The datasheet doesn't say which way round the
  42          * NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
  43          * 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS
  44          */
  45         while (__raw_readl(rtc_data->io + HW_RTC_STAT) &
  46                         BF(0x80, RTC_STAT_STALE_REGS))
  47                 cpu_relax();
  48 }
  49
  50 /* Time read/write */
  51 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
  52 {
  53         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  54
  55         stmp3xxx_wait_time(rtc_data);
  56         rtc_time_to_tm(__raw_readl(rtc_data->io + HW_RTC_SECONDS), rtc_tm);
  57         return 0;
  58 }
  59
  60 static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t)
  61 {
  62         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  63
  64         __raw_writel(t, rtc_data->io + HW_RTC_SECONDS);
  65         stmp3xxx_wait_time(rtc_data);
  66         return 0;
  67 }
  68
  69 /* interrupt(s) handler */
  70 static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
  71 {
  72         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
  73         u32 status;
  74         u32 events = 0;
  75
  76         status = __raw_readl(rtc_data->io + HW_RTC_CTRL) &
  77                         (BM_RTC_CTRL_ALARM_IRQ | BM_RTC_CTRL_ONEMSEC_IRQ);
  78
  79         if (status & BM_RTC_CTRL_ALARM_IRQ) {
  80                 stmp3xxx_clearl(BM_RTC_CTRL_ALARM_IRQ,
  81                                 rtc_data->io + HW_RTC_CTRL);
  82                 events |= RTC_AF | RTC_IRQF;
  83         }
  84
  85         if (status & BM_RTC_CTRL_ONEMSEC_IRQ) {
  86                 stmp3xxx_clearl(BM_RTC_CTRL_ONEMSEC_IRQ,
  87                                 rtc_data->io + HW_RTC_CTRL);
  88                 if (++rtc_data->irq_count % 1000 == 0) {
  89                         events |= RTC_UF | RTC_IRQF;
  90                         rtc_data->irq_count = 0;
  91                 }
  92         }
  93
  94         if (events)
  95                 rtc_update_irq(rtc_data->rtc, 1, events);
  96
  97         return IRQ_HANDLED;
  98 }
  99
 100 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 101 {
 102         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 103         void __iomem *p = rtc_data->io + HW_RTC_PERSISTENT0,
 104                      *ctl = rtc_data->io + HW_RTC_CTRL;
 105
 106         if (enabled) {
 107                 stmp3xxx_setl(BM_RTC_PERSISTENT0_ALARM_EN |
 108                               BM_RTC_PERSISTENT0_ALARM_WAKE_EN, p);
 109                 stmp3xxx_setl(BM_RTC_CTRL_ALARM_IRQ_EN, ctl);
 110         } else {
 111                 stmp3xxx_clearl(BM_RTC_PERSISTENT0_ALARM_EN |
 112                               BM_RTC_PERSISTENT0_ALARM_WAKE_EN, p);
 113                 stmp3xxx_clearl(BM_RTC_CTRL_ALARM_IRQ_EN, ctl);
 114         }
 115         return 0;
 116 }
 117
 118 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 119 {
 120         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 121
 122         rtc_time_to_tm(__raw_readl(rtc_data->io + HW_RTC_ALARM), &alm->time);
 123         return 0;
 124 }
 125
 126 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 127 {
 128         unsigned long t;
 129         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 130
 131         rtc_tm_to_time(&alm->time, &t);
 132         __raw_writel(t, rtc_data->io + HW_RTC_ALARM);
 133         return 0;
 134 }
 135
 136 static struct rtc_class_ops stmp3xxx_rtc_ops = {
 137         .alarm_irq_enable =
 138                           stmp3xxx_alarm_irq_enable,
 139         .read_time      = stmp3xxx_rtc_gettime,
 140         .set_mmss       = stmp3xxx_rtc_set_mmss,
 141         .read_alarm     = stmp3xxx_rtc_read_alarm,
 142         .set_alarm      = stmp3xxx_rtc_set_alarm,
 143 };
 144
 145 static int stmp3xxx_rtc_remove(struct platform_device *pdev)
 146 {
 147         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
 148
 149         if (!rtc_data)
 150                 return 0;
 151
 152         stmp3xxx_clearl(BM_RTC_CTRL_ONEMSEC_IRQ_EN | BM_RTC_CTRL_ALARM_IRQ_EN,
 153                         rtc_data->io + HW_RTC_CTRL);
 154         free_irq(rtc_data->irq_alarm, &pdev->dev);
 155         free_irq(rtc_data->irq_1msec, &pdev->dev);
 156         rtc_device_unregister(rtc_data->rtc);
 157         iounmap(rtc_data->io);
 158         kfree(rtc_data);
 159
 160         return 0;
 161 }
 162
 163 static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 164 {
 165         struct stmp3xxx_rtc_data *rtc_data;
 166         struct resource *r;
 167         int err;
 168
 169         rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
 170         if (!rtc_data)
 171                 return -ENOMEM;
 172
 173         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 174         if (!r) {
 175                 dev_err(&pdev->dev, "failed to get resource\n");
 176                 err = -ENXIO;
 177                 goto out_free;
 178         }
 179
 180         rtc_data->io = ioremap(r->start, resource_size(r));
 181         if (!rtc_data->io) {
 182                 dev_err(&pdev->dev, "ioremap failed\n");
 183                 err = -EIO;
 184                 goto out_free;
 185         }
 186
 187         rtc_data->irq_alarm = platform_get_irq(pdev, 0);
 188         rtc_data->irq_1msec = platform_get_irq(pdev, 1);
 189
 190         if (!(__raw_readl(HW_RTC_STAT + rtc_data->io) &
 191                         BM_RTC_STAT_RTC_PRESENT)) {
 192                 dev_err(&pdev->dev, "no device onboard\n");
 193                 err = -ENODEV;
 194                 goto out_remap;
 195         }
 196
 197         stmp3xxx_reset_block(rtc_data->io, true);
 198         stmp3xxx_clearl(BM_RTC_PERSISTENT0_ALARM_EN |
 199                         BM_RTC_PERSISTENT0_ALARM_WAKE_EN |
 200                         BM_RTC_PERSISTENT0_ALARM_WAKE,
 201                         rtc_data->io + HW_RTC_PERSISTENT0);
 202         rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
 203                                 &stmp3xxx_rtc_ops, THIS_MODULE);
 204         if (IS_ERR(rtc_data->rtc)) {
 205                 err = PTR_ERR(rtc_data->rtc);
 206                 goto out_remap;
 207         }
 208
 209         rtc_data->irq_count = 0;
 210         err = request_irq(rtc_data->irq_alarm, stmp3xxx_rtc_interrupt,
 211                         IRQF_DISABLED, "RTC alarm", &pdev->dev);
 212         if (err) {
 213                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 214                         rtc_data->irq_alarm);
 215                 goto out_irq_alarm;
 216         }
 217         err = request_irq(rtc_data->irq_1msec, stmp3xxx_rtc_interrupt,
 218                         IRQF_DISABLED, "RTC tick", &pdev->dev);
 219         if (err) {
 220                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 221                         rtc_data->irq_1msec);
 222                 goto out_irq1;
 223         }
 224
 225         platform_set_drvdata(pdev, rtc_data);
 226
 227         return 0;
 228
 229 out_irq1:
 230         free_irq(rtc_data->irq_alarm, &pdev->dev);
 231 out_irq_alarm:
 232         stmp3xxx_clearl(BM_RTC_CTRL_ONEMSEC_IRQ_EN | BM_RTC_CTRL_ALARM_IRQ_EN,
 233                         rtc_data->io + HW_RTC_CTRL);
 234         rtc_device_unregister(rtc_data->rtc);
 235 out_remap:
 236         iounmap(rtc_data->io);
 237 out_free:
 238         kfree(rtc_data);
 239         return err;
 240 }
 241
 242 #ifdef CONFIG_PM
 243 static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 244 {
 245         return 0;
 246 }
 247
 248 static int stmp3xxx_rtc_resume(struct platform_device *dev)
 249 {
 250         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);
 251
 252         stmp3xxx_reset_block(rtc_data->io, true);
 253         stmp3xxx_clearl(BM_RTC_PERSISTENT0_ALARM_EN |
 254                         BM_RTC_PERSISTENT0_ALARM_WAKE_EN |
 255                         BM_RTC_PERSISTENT0_ALARM_WAKE,
 256                         rtc_data->io + HW_RTC_PERSISTENT0);
 257         return 0;
 258 }
 259 #else
 260 #define stmp3xxx_rtc_suspend    NULL
 261 #define stmp3xxx_rtc_resume     NULL
 262 #endif
 263
 264 static struct platform_driver stmp3xxx_rtcdrv = {
 265         .probe          = stmp3xxx_rtc_probe,
 266         .remove         = stmp3xxx_rtc_remove,
 267         .suspend        = stmp3xxx_rtc_suspend,
 268         .resume         = stmp3xxx_rtc_resume,
 269         .driver         = {
 270                 .name   = "stmp3xxx-rtc",
 271                 .owner  = THIS_MODULE,
 272         },
 273 };
 274
 275 static int __init stmp3xxx_rtc_init(void)
 276 {
 277         return platform_driver_register(&stmp3xxx_rtcdrv);
 278 }
 279
 280 static void __exit stmp3xxx_rtc_exit(void)
 281 {
 282         platform_driver_unregister(&stmp3xxx_rtcdrv);
 283 }
 284
 285 module_init(stmp3xxx_rtc_init);
 286 module_exit(stmp3xxx_rtc_exit);
 287
 288 MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 289 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com>");
 290 MODULE_LICENSE("GPL");