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/mod_devicetable.h>
  30 #include <linux/clk.h>
  31
  32 #define DRV_NAME        "rtc-ftrtc010"
  33
  34 MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
  35 MODULE_DESCRIPTION("RTC driver for Gemini SoC");
  36 MODULE_LICENSE("GPL");
  37 MODULE_ALIAS("platform:" DRV_NAME);
  38
  39 struct ftrtc010_rtc {
  40         struct rtc_device       *rtc_dev;
  41         void __iomem            *rtc_base;
  42         int                     rtc_irq;
  43         struct clk              *pclk;
  44         struct clk              *extclk;
  45 };
  46
  47 enum ftrtc010_rtc_offsets {
  48         FTRTC010_RTC_SECOND             = 0x00,
  49         FTRTC010_RTC_MINUTE             = 0x04,
  50         FTRTC010_RTC_HOUR               = 0x08,
  51         FTRTC010_RTC_DAYS               = 0x0C,
  52         FTRTC010_RTC_ALARM_SECOND       = 0x10,
  53         FTRTC010_RTC_ALARM_MINUTE       = 0x14,
  54         FTRTC010_RTC_ALARM_HOUR         = 0x18,
  55         FTRTC010_RTC_RECORD             = 0x1C,
  56         FTRTC010_RTC_CR                 = 0x20,
  57 };
  58
  59 static irqreturn_t ftrtc010_rtc_interrupt(int irq, void *dev)
  60 {
  61         return IRQ_HANDLED;
  62 }
  63
  64 /*
  65  * Looks like the RTC in the Gemini SoC is (totaly) broken
  66  * We can't read/write directly the time from RTC registers.
  67  * We must do some "offset" calculation to get the real time
  68  *
  69  * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
  70  * the same thing, without the rtc-lib.c calls.
  71  */
  72
  73 static int ftrtc010_rtc_read_time(struct device *dev, struct rtc_time *tm)
  74 {
  75         struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
  76
  77         u32 days, hour, min, sec, offset;
  78         timeu64_t time;
  79
  80         sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
  81         min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
  82         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
  83         days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
  84         offset = readl(rtc->rtc_base + FTRTC010_RTC_RECORD);
  85
  86         time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
  87
  88         rtc_time64_to_tm(time, tm);
  89
  90         return 0;
  91 }
  92
  93 static int ftrtc010_rtc_set_time(struct device *dev, struct rtc_time *tm)
  94 {
  95         struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
  96         u32 sec, min, hour, day, offset;
  97         timeu64_t time;
  98
  99         time = rtc_tm_to_time64(tm);
 100
 101         sec = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 102         min = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 103         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 104         day = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 105
 106         offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
 107
 108         writel(offset, rtc->rtc_base + FTRTC010_RTC_RECORD);
 109         writel(0x01, rtc->rtc_base + FTRTC010_RTC_CR);
 110
 111         return 0;
 112 }
 113
 114 static const struct rtc_class_ops ftrtc010_rtc_ops = {
 115         .read_time     = ftrtc010_rtc_read_time,
 116         .set_time      = ftrtc010_rtc_set_time,
 117 };
 118
 119 static int ftrtc010_rtc_probe(struct platform_device *pdev)
 120 {
 121         u32 days, hour, min, sec;
 122         struct ftrtc010_rtc *rtc;
 123         struct device *dev = &pdev->dev;
 124         struct resource *res;
 125         int ret;
 126
 127         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 128         if (unlikely(!rtc))
 129                 return -ENOMEM;
 130         platform_set_drvdata(pdev, rtc);
 131
 132         rtc->pclk = devm_clk_get(dev, "PCLK");
 133         if (IS_ERR(rtc->pclk)) {
 134                 dev_err(dev, "could not get PCLK\n");
 135         } else {
 136                 ret = clk_prepare_enable(rtc->pclk);
 137                 if (ret) {
 138                         dev_err(dev, "failed to enable PCLK\n");
 139                         return ret;
 140                 }
 141         }
 142         rtc->extclk = devm_clk_get(dev, "EXTCLK");
 143         if (IS_ERR(rtc->extclk)) {
 144                 dev_err(dev, "could not get EXTCLK\n");
 145         } else {
 146                 ret = clk_prepare_enable(rtc->extclk);
 147                 if (ret) {
 148                         dev_err(dev, "failed to enable EXTCLK\n");
 149                         return ret;
 150                 }
 151         }
 152
 153         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 154         if (!res)
 155                 return -ENODEV;
 156
 157         rtc->rtc_irq = res->start;
 158
 159         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 160         if (!res)
 161                 return -ENODEV;
 162
 163         rtc->rtc_base = devm_ioremap(dev, res->start,
 164                                      resource_size(res));
 165         if (!rtc->rtc_base)
 166                 return -ENOMEM;
 167
 168         rtc->rtc_dev = devm_rtc_allocate_device(dev);
 169         if (IS_ERR(rtc->rtc_dev))
 170                 return PTR_ERR(rtc->rtc_dev);
 171
 172         rtc->rtc_dev->ops = &ftrtc010_rtc_ops;
 173
 174         sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 175         min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 176         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 177         days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 178
 179         rtc->rtc_dev->range_min = (u64)days * 86400 + hour * 3600 +
 180                                   min * 60 + sec;
 181         rtc->rtc_dev->range_max = U32_MAX + rtc->rtc_dev->range_min;
 182
 183         ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
 184                                IRQF_SHARED, pdev->name, dev);
 185         if (unlikely(ret))
 186                 return ret;
 187
 188         return rtc_register_device(rtc->rtc_dev);
 189 }
 190
 191 static int ftrtc010_rtc_remove(struct platform_device *pdev)
 192 {
 193         struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
 194
 195         if (!IS_ERR(rtc->extclk))
 196                 clk_disable_unprepare(rtc->extclk);
 197         if (!IS_ERR(rtc->pclk))
 198                 clk_disable_unprepare(rtc->pclk);
 199
 200         return 0;
 201 }
 202
 203 static const struct of_device_id ftrtc010_rtc_dt_match[] = {
 204         { .compatible = "cortina,gemini-rtc" },
 205         { .compatible = "faraday,ftrtc010" },
 206         { }
 207 };
 208 MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
 209
 210 static struct platform_driver ftrtc010_rtc_driver = {
 211         .driver         = {
 212                 .name   = DRV_NAME,
 213                 .of_match_table = ftrtc010_rtc_dt_match,
 214         },
 215         .probe          = ftrtc010_rtc_probe,
 216         .remove         = ftrtc010_rtc_remove,
 217 };
 218
 219 module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);