drivers/rtc/rtc-ftrtc010.c

   1 /*
   2  *  Faraday Technology FTRTC010 driver
   3  *
   4  *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * Original code for older kernel 2.6.15 are from Stormlinksemi
  17  * first update from Janos Laube for > 2.6.29 kernels
  18  *
  19  * checkpatch fixes and usage of rtc-lib code
  20  * Hans Ulli Kroll <ulli.kroll@googlemail.com>
  21  */
  22
  23 #include <linux/rtc.h>
  24 #include <linux/io.h>
  25 #include <linux/slab.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/clk.h>
  30
  31 #define DRV_NAME        "rtc-ftrtc010"
  32
  33 MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
  34 MODULE_DESCRIPTION("RTC driver for Gemini SoC");
  35 MODULE_LICENSE("GPL");
  36 MODULE_ALIAS("platform:" DRV_NAME);
  37
  38 struct ftrtc010_rtc {
  39         struct rtc_device       *rtc_dev;
  40         void __iomem            *rtc_base;
  41         int                     rtc_irq;
  42         struct clk              *pclk;
  43         struct clk              *extclk;
  44 };
  45
  46 enum ftrtc010_rtc_offsets {
  47         FTRTC010_RTC_SECOND             = 0x00,
  48         FTRTC010_RTC_MINUTE             = 0x04,
  49         FTRTC010_RTC_HOUR               = 0x08,
  50         FTRTC010_RTC_DAYS               = 0x0C,
  51         FTRTC010_RTC_ALARM_SECOND       = 0x10,
  52         FTRTC010_RTC_ALARM_MINUTE       = 0x14,
  53         FTRTC010_RTC_ALARM_HOUR         = 0x18,
  54         FTRTC010_RTC_RECORD             = 0x1C,
  55         FTRTC010_RTC_CR                 = 0x20,
  56 };
  57
  58 static irqreturn_t ftrtc010_rtc_interrupt(int irq, void *dev)
  59 {
  60         return IRQ_HANDLED;
  61 }
  62
  63 /*
  64  * Looks like the RTC in the Gemini SoC is (totaly) broken
  65  * We can't read/write directly the time from RTC registers.
  66  * We must do some "offset" calculation to get the real time
  67  *
  68  * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
  69  * the same thing, without the rtc-lib.c calls.
  70  */
  71
  72 static int ftrtc010_rtc_read_time(struct device *dev, struct rtc_time *tm)
  73 {
  74         struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
  75
  76         u32 days, hour, min, sec, offset;
  77         timeu64_t time;
  78
  79         sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
  80         min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
  81         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
  82         days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
  83         offset = readl(rtc->rtc_base + FTRTC010_RTC_RECORD);
  84
  85         time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
  86
  87         rtc_time64_to_tm(time, tm);
  88
  89         return 0;
  90 }
  91
  92 static int ftrtc010_rtc_set_time(struct device *dev, struct rtc_time *tm)
  93 {
  94         struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
  95         u32 sec, min, hour, day, offset;
  96         timeu64_t time;
  97
  98         time = rtc_tm_to_time64(tm);
  99
 100         sec = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 101         min = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 102         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 103         day = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 104
 105         offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
 106
 107         writel(offset, rtc->rtc_base + FTRTC010_RTC_RECORD);
 108         writel(0x01, rtc->rtc_base + FTRTC010_RTC_CR);
 109
 110         return 0;
 111 }
 112
 113 static const struct rtc_class_ops ftrtc010_rtc_ops = {
 114         .read_time     = ftrtc010_rtc_read_time,
 115         .set_time      = ftrtc010_rtc_set_time,
 116 };
 117
 118 static int ftrtc010_rtc_probe(struct platform_device *pdev)
 119 {
 120         u32 days, hour, min, sec;
 121         struct ftrtc010_rtc *rtc;
 122         struct device *dev = &pdev->dev;
 123         struct resource *res;
 124         int ret;
 125
 126         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 127         if (unlikely(!rtc))
 128                 return -ENOMEM;
 129         platform_set_drvdata(pdev, rtc);
 130
 131         rtc->pclk = devm_clk_get(dev, "PCLK");
 132         if (IS_ERR(rtc->pclk)) {
 133                 dev_err(dev, "could not get PCLK\n");
 134         } else {
 135                 ret = clk_prepare_enable(rtc->pclk);
 136                 if (ret) {
 137                         dev_err(dev, "failed to enable PCLK\n");
 138                         return ret;
 139                 }
 140         }
 141         rtc->extclk = devm_clk_get(dev, "EXTCLK");
 142         if (IS_ERR(rtc->extclk)) {
 143                 dev_err(dev, "could not get EXTCLK\n");
 144         } else {
 145                 ret = clk_prepare_enable(rtc->extclk);
 146                 if (ret) {
 147                         dev_err(dev, "failed to enable EXTCLK\n");
 148                         return ret;
 149                 }
 150         }
 151
 152         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 153         if (!res)
 154                 return -ENODEV;
 155
 156         rtc->rtc_irq = res->start;
 157
 158         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 159         if (!res)
 160                 return -ENODEV;
 161
 162         rtc->rtc_base = devm_ioremap(dev, res->start,
 163                                      resource_size(res));
 164         if (!rtc->rtc_base)
 165                 return -ENOMEM;
 166
 167         rtc->rtc_dev = devm_rtc_allocate_device(dev);
 168         if (IS_ERR(rtc->rtc_dev))
 169                 return PTR_ERR(rtc->rtc_dev);
 170
 171         rtc->rtc_dev->ops = &ftrtc010_rtc_ops;
 172
 173         sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 174         min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 175         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 176         days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 177
 178         rtc->rtc_dev->range_min = (u64)days * 86400 + hour * 3600 +
 179                                   min * 60 + sec;
 180         rtc->rtc_dev->range_max = U32_MAX + rtc->rtc_dev->range_min;
 181
 182         ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
 183                                IRQF_SHARED, pdev->name, dev);
 184         if (unlikely(ret))
 185                 return ret;
 186
 187         return rtc_register_device(rtc->rtc_dev);
 188 }
 189
 190 static int ftrtc010_rtc_remove(struct platform_device *pdev)
 191 {
 192         struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
 193
 194         if (!IS_ERR(rtc->extclk))
 195                 clk_disable_unprepare(rtc->extclk);
 196         if (!IS_ERR(rtc->pclk))
 197                 clk_disable_unprepare(rtc->pclk);
 198
 199         return 0;
 200 }
 201
 202 static const struct of_device_id ftrtc010_rtc_dt_match[] = {
 203         { .compatible = "cortina,gemini-rtc" },
 204         { .compatible = "faraday,ftrtc010" },
 205         { }
 206 };
 207 MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
 208
 209 static struct platform_driver ftrtc010_rtc_driver = {
 210         .driver         = {
 211                 .name   = DRV_NAME,
 212                 .of_match_table = ftrtc010_rtc_dt_match,
 213         },
 214         .probe          = ftrtc010_rtc_probe,
 215         .remove         = ftrtc010_rtc_remove,
 216 };
 217
 218 module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);