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         unsigned int  days, hour, min, sec;
  77         unsigned long offset, 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_time_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         unsigned int sec, min, hour, day;
  96         unsigned long offset, time;
  97
  98         if (tm->tm_year >= 2148)        /* EPOCH Year + 179 */
  99                 return -EINVAL;
 100
 101         rtc_tm_to_time(tm, &time);
 102
 103         sec = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 104         min = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 105         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 106         day = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 107
 108         offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
 109
 110         writel(offset, rtc->rtc_base + FTRTC010_RTC_RECORD);
 111         writel(0x01, rtc->rtc_base + FTRTC010_RTC_CR);
 112
 113         return 0;
 114 }
 115
 116 static const struct rtc_class_ops ftrtc010_rtc_ops = {
 117         .read_time     = ftrtc010_rtc_read_time,
 118         .set_time      = ftrtc010_rtc_set_time,
 119 };
 120
 121 static int ftrtc010_rtc_probe(struct platform_device *pdev)
 122 {
 123         struct ftrtc010_rtc *rtc;
 124         struct device *dev = &pdev->dev;
 125         struct resource *res;
 126         int ret;
 127
 128         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 129         if (unlikely(!rtc))
 130                 return -ENOMEM;
 131         platform_set_drvdata(pdev, rtc);
 132
 133         rtc->pclk = devm_clk_get(dev, "PCLK");
 134         if (IS_ERR(rtc->pclk)) {
 135                 dev_err(dev, "could not get PCLK\n");
 136         } else {
 137                 ret = clk_prepare_enable(rtc->pclk);
 138                 if (ret) {
 139                         dev_err(dev, "failed to enable PCLK\n");
 140                         return ret;
 141                 }
 142         }
 143         rtc->extclk = devm_clk_get(dev, "EXTCLK");
 144         if (IS_ERR(rtc->extclk)) {
 145                 dev_err(dev, "could not get EXTCLK\n");
 146         } else {
 147                 ret = clk_prepare_enable(rtc->extclk);
 148                 if (ret) {
 149                         dev_err(dev, "failed to enable EXTCLK\n");
 150                         return ret;
 151                 }
 152         }
 153
 154         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 155         if (!res)
 156                 return -ENODEV;
 157
 158         rtc->rtc_irq = res->start;
 159
 160         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 161         if (!res)
 162                 return -ENODEV;
 163
 164         rtc->rtc_base = devm_ioremap(dev, res->start,
 165                                      resource_size(res));
 166         if (!rtc->rtc_base)
 167                 return -ENOMEM;
 168
 169         ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
 170                                IRQF_SHARED, pdev->name, dev);
 171         if (unlikely(ret))
 172                 return ret;
 173
 174         rtc->rtc_dev = rtc_device_register(pdev->name, dev,
 175                                            &ftrtc010_rtc_ops, THIS_MODULE);
 176         return PTR_ERR_OR_ZERO(rtc->rtc_dev);
 177 }
 178
 179 static int ftrtc010_rtc_remove(struct platform_device *pdev)
 180 {
 181         struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
 182
 183         if (!IS_ERR(rtc->extclk))
 184                 clk_disable_unprepare(rtc->extclk);
 185         if (!IS_ERR(rtc->pclk))
 186                 clk_disable_unprepare(rtc->pclk);
 187         rtc_device_unregister(rtc->rtc_dev);
 188
 189         return 0;
 190 }
 191
 192 static const struct of_device_id ftrtc010_rtc_dt_match[] = {
 193         { .compatible = "cortina,gemini-rtc" },
 194         { .compatible = "faraday,ftrtc010" },
 195         { }
 196 };
 197 MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
 198
 199 static struct platform_driver ftrtc010_rtc_driver = {
 200         .driver         = {
 201                 .name   = DRV_NAME,
 202                 .of_match_table = ftrtc010_rtc_dt_match,
 203         },
 204         .probe          = ftrtc010_rtc_probe,
 205         .remove         = ftrtc010_rtc_remove,
 206 };
 207
 208 module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);