drivers/rtc/rtc-coh901331.c

   1 /*
   2  * Copyright (C) 2007-2009 ST-Ericsson AB
   3  * License terms: GNU General Public License (GPL) version 2
   4  * Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.
   5  * Author: Linus Walleij <linus.walleij@stericsson.com>
   6  * Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>
   7  * Copyright 2006 (c) MontaVista Software, Inc.
   8  */
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/rtc.h>
  12 #include <linux/clk.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/pm.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/io.h>
  17
  18 /*
  19  * Registers in the COH 901 331
  20  */
  21 /* Alarm value 32bit (R/W) */
  22 #define COH901331_ALARM         0x00U
  23 /* Used to set current time 32bit (R/W) */
  24 #define COH901331_SET_TIME      0x04U
  25 /* Indication if current time is valid 32bit (R/-) */
  26 #define COH901331_VALID         0x08U
  27 /* Read the current time 32bit (R/-) */
  28 #define COH901331_CUR_TIME      0x0cU
  29 /* Event register for the "alarm" interrupt */
  30 #define COH901331_IRQ_EVENT     0x10U
  31 /* Mask register for the "alarm" interrupt */
  32 #define COH901331_IRQ_MASK      0x14U
  33 /* Force register for the "alarm" interrupt */
  34 #define COH901331_IRQ_FORCE     0x18U
  35
  36 /*
  37  * Reference to RTC block clock
  38  * Notice that the frequent clk_enable()/clk_disable() on this
  39  * clock is mainly to be able to turn on/off other clocks in the
  40  * hierarchy as needed, the RTC clock is always on anyway.
  41  */
  42 struct coh901331_port {
  43         struct rtc_device *rtc;
  44         struct clk *clk;
  45         u32 phybase;
  46         u32 physize;
  47         void __iomem *virtbase;
  48         int irq;
  49 #ifdef CONFIG_PM
  50         u32 irqmaskstore;
  51 #endif
  52 };
  53
  54 static irqreturn_t coh901331_interrupt(int irq, void *data)
  55 {
  56         struct coh901331_port *rtap = data;
  57
  58         clk_enable(rtap->clk);
  59         /* Ack IRQ */
  60         writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
  61         clk_disable(rtap->clk);
  62         /* Set alarm flag */
  63         rtc_update_irq(rtap->rtc, 1, RTC_AF);
  64
  65         return IRQ_HANDLED;
  66 }
  67
  68 static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
  69 {
  70         struct coh901331_port *rtap = dev_get_drvdata(dev);
  71
  72         clk_enable(rtap->clk);
  73         /* Check if the time is valid */
  74         if (readl(rtap->virtbase + COH901331_VALID)) {
  75                 rtc_time_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
  76                 clk_disable(rtap->clk);
  77                 return rtc_valid_tm(tm);
  78         }
  79         clk_disable(rtap->clk);
  80         return -EINVAL;
  81 }
  82
  83 static int coh901331_set_mmss(struct device *dev, unsigned long secs)
  84 {
  85         struct coh901331_port *rtap = dev_get_drvdata(dev);
  86
  87         clk_enable(rtap->clk);
  88         writel(secs, rtap->virtbase + COH901331_SET_TIME);
  89         clk_disable(rtap->clk);
  90
  91         return 0;
  92 }
  93
  94 static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
  95 {
  96         struct coh901331_port *rtap = dev_get_drvdata(dev);
  97
  98         clk_enable(rtap->clk);
  99         rtc_time_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
 100         alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
 101         alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
 102         clk_disable(rtap->clk);
 103
 104         return 0;
 105 }
 106
 107 static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 108 {
 109         struct coh901331_port *rtap = dev_get_drvdata(dev);
 110         unsigned long time;
 111
 112         rtc_tm_to_time(&alarm->time, &time);
 113         clk_enable(rtap->clk);
 114         writel(time, rtap->virtbase + COH901331_ALARM);
 115         writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
 116         clk_disable(rtap->clk);
 117
 118         return 0;
 119 }
 120
 121 static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
 122 {
 123         struct coh901331_port *rtap = dev_get_drvdata(dev);
 124
 125         clk_enable(rtap->clk);
 126         if (enabled)
 127                 writel(1, rtap->virtbase + COH901331_IRQ_MASK);
 128         else
 129                 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
 130         clk_disable(rtap->clk);
 131 }
 132
 133 static struct rtc_class_ops coh901331_ops = {
 134         .read_time = coh901331_read_time,
 135         .set_mmss = coh901331_set_mmss,
 136         .read_alarm = coh901331_read_alarm,
 137         .set_alarm = coh901331_set_alarm,
 138         .alarm_irq_enable = coh901331_alarm_irq_enable,
 139 };
 140
 141 static int __exit coh901331_remove(struct platform_device *pdev)
 142 {
 143         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
 144
 145         if (rtap) {
 146                 free_irq(rtap->irq, rtap);
 147                 rtc_device_unregister(rtap->rtc);
 148                 clk_put(rtap->clk);
 149                 iounmap(rtap->virtbase);
 150                 release_mem_region(rtap->phybase, rtap->physize);
 151                 platform_set_drvdata(pdev, NULL);
 152                 kfree(rtap);
 153         }
 154
 155         return 0;
 156 }
 157
 158
 159 static int __init coh901331_probe(struct platform_device *pdev)
 160 {
 161         int ret;
 162         struct coh901331_port *rtap;
 163         struct resource *res;
 164
 165         rtap = kzalloc(sizeof(struct coh901331_port), GFP_KERNEL);
 166         if (!rtap)
 167                 return -ENOMEM;
 168
 169         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 170         if (!res) {
 171                 ret = -ENOENT;
 172                 goto out_no_resource;
 173         }
 174         rtap->phybase = res->start;
 175         rtap->physize = resource_size(res);
 176
 177         if (request_mem_region(rtap->phybase, rtap->physize,
 178                                "rtc-coh901331") == NULL) {
 179                 ret = -EBUSY;
 180                 goto out_no_memregion;
 181         }
 182
 183         rtap->virtbase = ioremap(rtap->phybase, rtap->physize);
 184         if (!rtap->virtbase) {
 185                 ret = -ENOMEM;
 186                 goto out_no_remap;
 187         }
 188
 189         rtap->irq = platform_get_irq(pdev, 0);
 190         if (request_irq(rtap->irq, coh901331_interrupt, IRQF_DISABLED,
 191                         "RTC COH 901 331 Alarm", rtap)) {
 192                 ret = -EIO;
 193                 goto out_no_irq;
 194         }
 195
 196         rtap->clk = clk_get(&pdev->dev, NULL);
 197         if (IS_ERR(rtap->clk)) {
 198                 ret = PTR_ERR(rtap->clk);
 199                 dev_err(&pdev->dev, "could not get clock\n");
 200                 goto out_no_clk;
 201         }
 202
 203         /* We enable/disable the clock only to assure it works */
 204         ret = clk_enable(rtap->clk);
 205         if (ret) {
 206                 dev_err(&pdev->dev, "could not enable clock\n");
 207                 goto out_no_clk_enable;
 208         }
 209         clk_disable(rtap->clk);
 210
 211         rtap->rtc = rtc_device_register("coh901331", &pdev->dev, &coh901331_ops,
 212                                          THIS_MODULE);
 213         if (IS_ERR(rtap->rtc)) {
 214                 ret = PTR_ERR(rtap->rtc);
 215                 goto out_no_rtc;
 216         }
 217
 218         platform_set_drvdata(pdev, rtap);
 219
 220         return 0;
 221
 222  out_no_rtc:
 223  out_no_clk_enable:
 224         clk_put(rtap->clk);
 225  out_no_clk:
 226         free_irq(rtap->irq, rtap);
 227  out_no_irq:
 228         iounmap(rtap->virtbase);
 229  out_no_remap:
 230         platform_set_drvdata(pdev, NULL);
 231  out_no_memregion:
 232         release_mem_region(rtap->phybase, SZ_4K);
 233  out_no_resource:
 234         kfree(rtap);
 235         return ret;
 236 }
 237
 238 #ifdef CONFIG_PM
 239 static int coh901331_suspend(struct platform_device *pdev, pm_message_t state)
 240 {
 241         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
 242
 243         /*
 244          * If this RTC alarm will be used for waking the system up,
 245          * don't disable it of course. Else we just disable the alarm
 246          * and await suspension.
 247          */
 248         if (device_may_wakeup(&pdev->dev)) {
 249                 enable_irq_wake(rtap->irq);
 250         } else {
 251                 clk_enable(rtap->clk);
 252                 rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
 253                 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
 254                 clk_disable(rtap->clk);
 255         }
 256         return 0;
 257 }
 258
 259 static int coh901331_resume(struct platform_device *pdev)
 260 {
 261         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
 262
 263         if (device_may_wakeup(&pdev->dev))
 264                 disable_irq_wake(rtap->irq);
 265         else
 266                 clk_enable(rtap->clk);
 267                 writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
 268                 clk_disable(rtap->clk);
 269         return 0;
 270 }
 271 #else
 272 #define coh901331_suspend NULL
 273 #define coh901331_resume NULL
 274 #endif
 275
 276 static void coh901331_shutdown(struct platform_device *pdev)
 277 {
 278         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
 279
 280         clk_enable(rtap->clk);
 281         writel(0, rtap->virtbase + COH901331_IRQ_MASK);
 282         clk_disable(rtap->clk);
 283 }
 284
 285 static struct platform_driver coh901331_driver = {
 286         .driver = {
 287                 .name = "rtc-coh901331",
 288                 .owner = THIS_MODULE,
 289         },
 290         .remove = __exit_p(coh901331_remove),
 291         .suspend = coh901331_suspend,
 292         .resume = coh901331_resume,
 293         .shutdown = coh901331_shutdown,
 294 };
 295
 296 static int __init coh901331_init(void)
 297 {
 298         return platform_driver_probe(&coh901331_driver, coh901331_probe);
 299 }
 300
 301 static void __exit coh901331_exit(void)
 302 {
 303         platform_driver_unregister(&coh901331_driver);
 304 }
 305
 306 module_init(coh901331_init);
 307 module_exit(coh901331_exit);
 308
 309 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
 310 MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
 311 MODULE_LICENSE("GPL");