kernel/drivers/rtc/rtc-armada38x.c

   1 /*
   2  * RTC driver for the Armada 38x Marvell SoCs
   3  *
   4  * Copyright (C) 2015 Marvell
   5  *
   6  * Gregory Clement <gregory.clement@free-electrons.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License, or (at your option) any later version.
  12  *
  13  */
  14
  15 #include <linux/delay.h>
  16 #include <linux/io.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/rtc.h>
  21
  22 #define RTC_STATUS          0x0
  23 #define RTC_STATUS_ALARM1           BIT(0)
  24 #define RTC_STATUS_ALARM2           BIT(1)
  25 #define RTC_IRQ1_CONF       0x4
  26 #define RTC_IRQ1_AL_EN              BIT(0)
  27 #define RTC_IRQ1_FREQ_EN            BIT(1)
  28 #define RTC_IRQ1_FREQ_1HZ           BIT(2)
  29 #define RTC_TIME            0xC
  30 #define RTC_ALARM1          0x10
  31
  32 #define SOC_RTC_INTERRUPT   0x8
  33 #define SOC_RTC_ALARM1          BIT(0)
  34 #define SOC_RTC_ALARM2          BIT(1)
  35 #define SOC_RTC_ALARM1_MASK     BIT(2)
  36 #define SOC_RTC_ALARM2_MASK     BIT(3)
  37
  38 struct armada38x_rtc {
  39         struct rtc_device   *rtc_dev;
  40         void __iomem        *regs;
  41         void __iomem        *regs_soc;
  42         spinlock_t          lock;
  43         int                 irq;
  44 };
  45
  46 /*
  47  * According to the datasheet, the OS should wait 5us after every
  48  * register write to the RTC hard macro so that the required update
  49  * can occur without holding off the system bus
  50  */
  51 static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset)
  52 {
  53         writel(val, rtc->regs + offset);
  54         udelay(5);
  55 }
  56
  57 static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  58 {
  59         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
  60         unsigned long time, time_check, flags;
  61
  62         spin_lock_irqsave(&rtc->lock, flags);
  63         time = readl(rtc->regs + RTC_TIME);
  64         /*
  65          * WA for failing time set attempts. As stated in HW ERRATA if
  66          * more than one second between two time reads is detected
  67          * then read once again.
  68          */
  69         time_check = readl(rtc->regs + RTC_TIME);
  70         if ((time_check - time) > 1)
  71                 time_check = readl(rtc->regs + RTC_TIME);
  72
  73         spin_unlock_irqrestore(&rtc->lock, flags);
  74
  75         rtc_time_to_tm(time_check, tm);
  76
  77         return 0;
  78 }
  79
  80 static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
  81 {
  82         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
  83         int ret = 0;
  84         unsigned long time, flags;
  85
  86         ret = rtc_tm_to_time(tm, &time);
  87
  88         if (ret)
  89                 goto out;
  90         /*
  91          * According to errata FE-3124064, Write to RTC TIME register
  92          * may fail. As a workaround, after writing to RTC TIME
  93          * register, issue a dummy write of 0x0 twice to RTC Status
  94          * register.
  95          */
  96         spin_lock_irqsave(&rtc->lock, flags);
  97         rtc_delayed_write(time, rtc, RTC_TIME);
  98         rtc_delayed_write(0, rtc, RTC_STATUS);
  99         rtc_delayed_write(0, rtc, RTC_STATUS);
 100         spin_unlock_irqrestore(&rtc->lock, flags);
 101
 102 out:
 103         return ret;
 104 }
 105
 106 static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 107 {
 108         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 109         unsigned long time, flags;
 110         u32 val;
 111
 112         spin_lock_irqsave(&rtc->lock, flags);
 113
 114         time = readl(rtc->regs + RTC_ALARM1);
 115         val = readl(rtc->regs + RTC_IRQ1_CONF) & RTC_IRQ1_AL_EN;
 116
 117         spin_unlock_irqrestore(&rtc->lock, flags);
 118
 119         alrm->enabled = val ? 1 : 0;
 120         rtc_time_to_tm(time,  &alrm->time);
 121
 122         return 0;
 123 }
 124
 125 static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 126 {
 127         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 128         unsigned long time, flags;
 129         int ret = 0;
 130         u32 val;
 131
 132         ret = rtc_tm_to_time(&alrm->time, &time);
 133
 134         if (ret)
 135                 goto out;
 136
 137         spin_lock_irqsave(&rtc->lock, flags);
 138
 139         rtc_delayed_write(time, rtc, RTC_ALARM1);
 140
 141         if (alrm->enabled) {
 142                         rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
 143                         val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
 144                         writel(val | SOC_RTC_ALARM1_MASK,
 145                                rtc->regs_soc + SOC_RTC_INTERRUPT);
 146         }
 147
 148         spin_unlock_irqrestore(&rtc->lock, flags);
 149
 150 out:
 151         return ret;
 152 }
 153
 154 static int armada38x_rtc_alarm_irq_enable(struct device *dev,
 155                                          unsigned int enabled)
 156 {
 157         struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 158         unsigned long flags;
 159
 160         spin_lock_irqsave(&rtc->lock, flags);
 161
 162         if (enabled)
 163                 rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
 164         else
 165                 rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
 166
 167         spin_unlock_irqrestore(&rtc->lock, flags);
 168
 169         return 0;
 170 }
 171
 172 static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
 173 {
 174         struct armada38x_rtc *rtc = data;
 175         u32 val;
 176         int event = RTC_IRQF | RTC_AF;
 177
 178         dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
 179
 180         spin_lock(&rtc->lock);
 181
 182         val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
 183
 184         writel(val & ~SOC_RTC_ALARM1, rtc->regs_soc + SOC_RTC_INTERRUPT);
 185         val = readl(rtc->regs + RTC_IRQ1_CONF);
 186         /* disable all the interrupts for alarm 1 */
 187         rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
 188         /* Ack the event */
 189         rtc_delayed_write(RTC_STATUS_ALARM1, rtc, RTC_STATUS);
 190
 191         spin_unlock(&rtc->lock);
 192
 193         if (val & RTC_IRQ1_FREQ_EN) {
 194                 if (val & RTC_IRQ1_FREQ_1HZ)
 195                         event |= RTC_UF;
 196                 else
 197                         event |= RTC_PF;
 198         }
 199
 200         rtc_update_irq(rtc->rtc_dev, 1, event);
 201
 202         return IRQ_HANDLED;
 203 }
 204
 205 static struct rtc_class_ops armada38x_rtc_ops = {
 206         .read_time = armada38x_rtc_read_time,
 207         .set_time = armada38x_rtc_set_time,
 208         .read_alarm = armada38x_rtc_read_alarm,
 209         .set_alarm = armada38x_rtc_set_alarm,
 210         .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
 211 };
 212
 213 static __init int armada38x_rtc_probe(struct platform_device *pdev)
 214 {
 215         struct resource *res;
 216         struct armada38x_rtc *rtc;
 217         int ret;
 218
 219         rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
 220                             GFP_KERNEL);
 221         if (!rtc)
 222                 return -ENOMEM;
 223
 224         spin_lock_init(&rtc->lock);
 225
 226         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
 227         rtc->regs = devm_ioremap_resource(&pdev->dev, res);
 228         if (IS_ERR(rtc->regs))
 229                 return PTR_ERR(rtc->regs);
 230         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
 231         rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
 232         if (IS_ERR(rtc->regs_soc))
 233                 return PTR_ERR(rtc->regs_soc);
 234
 235         rtc->irq = platform_get_irq(pdev, 0);
 236
 237         if (rtc->irq < 0) {
 238                 dev_err(&pdev->dev, "no irq\n");
 239                 return rtc->irq;
 240         }
 241         if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
 242                                 0, pdev->name, rtc) < 0) {
 243                 dev_warn(&pdev->dev, "Interrupt not available.\n");
 244                 rtc->irq = -1;
 245                 /*
 246                  * If there is no interrupt available then we can't
 247                  * use the alarm
 248                  */
 249                 armada38x_rtc_ops.set_alarm = NULL;
 250                 armada38x_rtc_ops.alarm_irq_enable = NULL;
 251         }
 252         platform_set_drvdata(pdev, rtc);
 253         if (rtc->irq != -1)
 254                 device_init_wakeup(&pdev->dev, 1);
 255
 256         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
 257                                         &armada38x_rtc_ops, THIS_MODULE);
 258         if (IS_ERR(rtc->rtc_dev)) {
 259                 ret = PTR_ERR(rtc->rtc_dev);
 260                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 261                 return ret;
 262         }
 263         return 0;
 264 }
 265
 266 #ifdef CONFIG_PM_SLEEP
 267 static int armada38x_rtc_suspend(struct device *dev)
 268 {
 269         if (device_may_wakeup(dev)) {
 270                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 271
 272                 return enable_irq_wake(rtc->irq);
 273         }
 274
 275         return 0;
 276 }
 277
 278 static int armada38x_rtc_resume(struct device *dev)
 279 {
 280         if (device_may_wakeup(dev)) {
 281                 struct armada38x_rtc *rtc = dev_get_drvdata(dev);
 282
 283                 return disable_irq_wake(rtc->irq);
 284         }
 285
 286         return 0;
 287 }
 288 #endif
 289
 290 static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
 291                          armada38x_rtc_suspend, armada38x_rtc_resume);
 292
 293 #ifdef CONFIG_OF
 294 static const struct of_device_id armada38x_rtc_of_match_table[] = {
 295         { .compatible = "marvell,armada-380-rtc", },
 296         {}
 297 };
 298 MODULE_DEVICE_TABLE(of, armada38x_rtc_of_match_table);
 299 #endif
 300
 301 static struct platform_driver armada38x_rtc_driver = {
 302         .driver         = {
 303                 .name   = "armada38x-rtc",
 304                 .pm     = &armada38x_rtc_pm_ops,
 305                 .of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
 306         },
 307 };
 308
 309 module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
 310
 311 MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
 312 MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
 313 MODULE_LICENSE("GPL");