drivers/rtc/rtc-ftrtc010.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Faraday Technology FTRTC010 driver
   4  *
   5  *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
   6  *
   7  * Original code for older kernel 2.6.15 are from Stormlinksemi
   8  * first update from Janos Laube for > 2.6.29 kernels
   9  *
  10  * checkpatch fixes and usage of rtc-lib code
  11  * Hans Ulli Kroll <ulli.kroll@googlemail.com>
  12  */
  13
  14 #include <linux/rtc.h>
  15 #include <linux/io.h>
  16 #include <linux/slab.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/mod_devicetable.h>
  21 #include <linux/clk.h>
  22
  23 #define DRV_NAME        "rtc-ftrtc010"
  24
  25 MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
  26 MODULE_DESCRIPTION("RTC driver for Gemini SoC");
  27 MODULE_LICENSE("GPL");
  28 MODULE_ALIAS("platform:" DRV_NAME);
  29
  30 struct ftrtc010_rtc {
  31         struct rtc_device       *rtc_dev;
  32         void __iomem            *rtc_base;
  33         int                     rtc_irq;
  34         struct clk              *pclk;
  35         struct clk              *extclk;
  36 };
  37
  38 enum ftrtc010_rtc_offsets {
  39         FTRTC010_RTC_SECOND             = 0x00,
  40         FTRTC010_RTC_MINUTE             = 0x04,
  41         FTRTC010_RTC_HOUR               = 0x08,
  42         FTRTC010_RTC_DAYS               = 0x0C,
  43         FTRTC010_RTC_ALARM_SECOND       = 0x10,
  44         FTRTC010_RTC_ALARM_MINUTE       = 0x14,
  45         FTRTC010_RTC_ALARM_HOUR         = 0x18,
  46         FTRTC010_RTC_RECORD             = 0x1C,
  47         FTRTC010_RTC_CR                 = 0x20,
  48 };
  49
  50 static irqreturn_t ftrtc010_rtc_interrupt(int irq, void *dev)
  51 {
  52         return IRQ_HANDLED;
  53 }
  54
  55 /*
  56  * Looks like the RTC in the Gemini SoC is (totaly) broken
  57  * We can't read/write directly the time from RTC registers.
  58  * We must do some "offset" calculation to get the real time
  59  *
  60  * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
  61  * the same thing, without the rtc-lib.c calls.
  62  */
  63
  64 static int ftrtc010_rtc_read_time(struct device *dev, struct rtc_time *tm)
  65 {
  66         struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
  67
  68         u32 days, hour, min, sec, offset;
  69         timeu64_t time;
  70
  71         sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
  72         min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
  73         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
  74         days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
  75         offset = readl(rtc->rtc_base + FTRTC010_RTC_RECORD);
  76
  77         time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
  78
  79         rtc_time64_to_tm(time, tm);
  80
  81         return 0;
  82 }
  83
  84 static int ftrtc010_rtc_set_time(struct device *dev, struct rtc_time *tm)
  85 {
  86         struct ftrtc010_rtc *rtc = dev_get_drvdata(dev);
  87         u32 sec, min, hour, day, offset;
  88         timeu64_t time;
  89
  90         time = rtc_tm_to_time64(tm);
  91
  92         sec = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
  93         min = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
  94         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
  95         day = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
  96
  97         offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
  98
  99         writel(offset, rtc->rtc_base + FTRTC010_RTC_RECORD);
 100         writel(0x01, rtc->rtc_base + FTRTC010_RTC_CR);
 101
 102         return 0;
 103 }
 104
 105 static const struct rtc_class_ops ftrtc010_rtc_ops = {
 106         .read_time     = ftrtc010_rtc_read_time,
 107         .set_time      = ftrtc010_rtc_set_time,
 108 };
 109
 110 static int ftrtc010_rtc_probe(struct platform_device *pdev)
 111 {
 112         u32 days, hour, min, sec;
 113         struct ftrtc010_rtc *rtc;
 114         struct device *dev = &pdev->dev;
 115         struct resource *res;
 116         int ret;
 117
 118         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 119         if (unlikely(!rtc))
 120                 return -ENOMEM;
 121         platform_set_drvdata(pdev, rtc);
 122
 123         rtc->pclk = devm_clk_get(dev, "PCLK");
 124         if (IS_ERR(rtc->pclk)) {
 125                 dev_err(dev, "could not get PCLK\n");
 126         } else {
 127                 ret = clk_prepare_enable(rtc->pclk);
 128                 if (ret) {
 129                         dev_err(dev, "failed to enable PCLK\n");
 130                         return ret;
 131                 }
 132         }
 133         rtc->extclk = devm_clk_get(dev, "EXTCLK");
 134         if (IS_ERR(rtc->extclk)) {
 135                 dev_err(dev, "could not get EXTCLK\n");
 136         } else {
 137                 ret = clk_prepare_enable(rtc->extclk);
 138                 if (ret) {
 139                         dev_err(dev, "failed to enable EXTCLK\n");
 140                         goto err_disable_pclk;
 141                 }
 142         }
 143
 144         rtc->rtc_irq = platform_get_irq(pdev, 0);
 145         if (rtc->rtc_irq < 0) {
 146                 ret = rtc->rtc_irq;
 147                 goto err_disable_extclk;
 148         }
 149
 150         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 151         if (!res) {
 152                 ret = -ENODEV;
 153                 goto err_disable_extclk;
 154         }
 155
 156         rtc->rtc_base = devm_ioremap(dev, res->start,
 157                                      resource_size(res));
 158         if (!rtc->rtc_base) {
 159                 ret = -ENOMEM;
 160                 goto err_disable_extclk;
 161         }
 162
 163         rtc->rtc_dev = devm_rtc_allocate_device(dev);
 164         if (IS_ERR(rtc->rtc_dev)) {
 165                 ret = PTR_ERR(rtc->rtc_dev);
 166                 goto err_disable_extclk;
 167         }
 168
 169         rtc->rtc_dev->ops = &ftrtc010_rtc_ops;
 170
 171         sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 172         min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 173         hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 174         days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 175
 176         rtc->rtc_dev->range_min = (u64)days * 86400 + hour * 3600 +
 177                                   min * 60 + sec;
 178         rtc->rtc_dev->range_max = U32_MAX + rtc->rtc_dev->range_min;
 179
 180         ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
 181                                IRQF_SHARED, pdev->name, dev);
 182         if (unlikely(ret))
 183                 goto err_disable_extclk;
 184
 185         return devm_rtc_register_device(rtc->rtc_dev);
 186
 187 err_disable_extclk:
 188         clk_disable_unprepare(rtc->extclk);
 189 err_disable_pclk:
 190         clk_disable_unprepare(rtc->pclk);
 191         return ret;
 192 }
 193
 194 static void ftrtc010_rtc_remove(struct platform_device *pdev)
 195 {
 196         struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
 197
 198         if (!IS_ERR(rtc->extclk))
 199                 clk_disable_unprepare(rtc->extclk);
 200         if (!IS_ERR(rtc->pclk))
 201                 clk_disable_unprepare(rtc->pclk);
 202 }
 203
 204 static const struct of_device_id ftrtc010_rtc_dt_match[] = {
 205         { .compatible = "cortina,gemini-rtc" },
 206         { .compatible = "faraday,ftrtc010" },
 207         { }
 208 };
 209 MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
 210
 211 static struct platform_driver ftrtc010_rtc_driver = {
 212         .driver         = {
 213                 .name   = DRV_NAME,
 214                 .of_match_table = ftrtc010_rtc_dt_match,
 215         },
 216         .probe          = ftrtc010_rtc_probe,
 217         .remove         = ftrtc010_rtc_remove,
 218 };
 219
 220 module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);