linux/drivers/rtc/rtc-ftrtc010.c
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   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
  25MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
  26MODULE_DESCRIPTION("RTC driver for Gemini SoC");
  27MODULE_LICENSE("GPL");
  28MODULE_ALIAS("platform:" DRV_NAME);
  29
  30struct 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
  38enum 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
  50static 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
  64static 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
  84static 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
 105static const struct rtc_class_ops ftrtc010_rtc_ops = {
 106        .read_time     = ftrtc010_rtc_read_time,
 107        .set_time      = ftrtc010_rtc_set_time,
 108};
 109
 110static 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                        return ret;
 141                }
 142        }
 143
 144        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 145        if (!res)
 146                return -ENODEV;
 147
 148        rtc->rtc_irq = res->start;
 149
 150        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 151        if (!res)
 152                return -ENODEV;
 153
 154        rtc->rtc_base = devm_ioremap(dev, res->start,
 155                                     resource_size(res));
 156        if (!rtc->rtc_base)
 157                return -ENOMEM;
 158
 159        rtc->rtc_dev = devm_rtc_allocate_device(dev);
 160        if (IS_ERR(rtc->rtc_dev))
 161                return PTR_ERR(rtc->rtc_dev);
 162
 163        rtc->rtc_dev->ops = &ftrtc010_rtc_ops;
 164
 165        sec  = readl(rtc->rtc_base + FTRTC010_RTC_SECOND);
 166        min  = readl(rtc->rtc_base + FTRTC010_RTC_MINUTE);
 167        hour = readl(rtc->rtc_base + FTRTC010_RTC_HOUR);
 168        days = readl(rtc->rtc_base + FTRTC010_RTC_DAYS);
 169
 170        rtc->rtc_dev->range_min = (u64)days * 86400 + hour * 3600 +
 171                                  min * 60 + sec;
 172        rtc->rtc_dev->range_max = U32_MAX + rtc->rtc_dev->range_min;
 173
 174        ret = devm_request_irq(dev, rtc->rtc_irq, ftrtc010_rtc_interrupt,
 175                               IRQF_SHARED, pdev->name, dev);
 176        if (unlikely(ret))
 177                return ret;
 178
 179        return devm_rtc_register_device(rtc->rtc_dev);
 180}
 181
 182static int ftrtc010_rtc_remove(struct platform_device *pdev)
 183{
 184        struct ftrtc010_rtc *rtc = platform_get_drvdata(pdev);
 185
 186        if (!IS_ERR(rtc->extclk))
 187                clk_disable_unprepare(rtc->extclk);
 188        if (!IS_ERR(rtc->pclk))
 189                clk_disable_unprepare(rtc->pclk);
 190
 191        return 0;
 192}
 193
 194static const struct of_device_id ftrtc010_rtc_dt_match[] = {
 195        { .compatible = "cortina,gemini-rtc" },
 196        { .compatible = "faraday,ftrtc010" },
 197        { }
 198};
 199MODULE_DEVICE_TABLE(of, ftrtc010_rtc_dt_match);
 200
 201static struct platform_driver ftrtc010_rtc_driver = {
 202        .driver         = {
 203                .name   = DRV_NAME,
 204                .of_match_table = ftrtc010_rtc_dt_match,
 205        },
 206        .probe          = ftrtc010_rtc_probe,
 207        .remove         = ftrtc010_rtc_remove,
 208};
 209
 210module_platform_driver_probe(ftrtc010_rtc_driver, ftrtc010_rtc_probe);
 211