linux/drivers/rtc/rtc-msm6242.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  Oki MSM6242 RTC Driver
   4 *
   5 *  Copyright 2009 Geert Uytterhoeven
   6 *
   7 *  Based on the A2000 TOD code in arch/m68k/amiga/config.c
   8 *  Copyright (C) 1993 Hamish Macdonald
   9 */
  10
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13#include <linux/delay.h>
  14#include <linux/io.h>
  15#include <linux/kernel.h>
  16#include <linux/module.h>
  17#include <linux/platform_device.h>
  18#include <linux/rtc.h>
  19#include <linux/slab.h>
  20
  21
  22enum {
  23        MSM6242_SECOND1         = 0x0,  /* 1-second digit register */
  24        MSM6242_SECOND10        = 0x1,  /* 10-second digit register */
  25        MSM6242_MINUTE1         = 0x2,  /* 1-minute digit register */
  26        MSM6242_MINUTE10        = 0x3,  /* 10-minute digit register */
  27        MSM6242_HOUR1           = 0x4,  /* 1-hour digit register */
  28        MSM6242_HOUR10          = 0x5,  /* PM/AM, 10-hour digit register */
  29        MSM6242_DAY1            = 0x6,  /* 1-day digit register */
  30        MSM6242_DAY10           = 0x7,  /* 10-day digit register */
  31        MSM6242_MONTH1          = 0x8,  /* 1-month digit register */
  32        MSM6242_MONTH10         = 0x9,  /* 10-month digit register */
  33        MSM6242_YEAR1           = 0xa,  /* 1-year digit register */
  34        MSM6242_YEAR10          = 0xb,  /* 10-year digit register */
  35        MSM6242_WEEK            = 0xc,  /* Week register */
  36        MSM6242_CD              = 0xd,  /* Control Register D */
  37        MSM6242_CE              = 0xe,  /* Control Register E */
  38        MSM6242_CF              = 0xf,  /* Control Register F */
  39};
  40
  41#define MSM6242_HOUR10_AM       (0 << 2)
  42#define MSM6242_HOUR10_PM       (1 << 2)
  43#define MSM6242_HOUR10_HR_MASK  (3 << 0)
  44
  45#define MSM6242_WEEK_SUNDAY     0
  46#define MSM6242_WEEK_MONDAY     1
  47#define MSM6242_WEEK_TUESDAY    2
  48#define MSM6242_WEEK_WEDNESDAY  3
  49#define MSM6242_WEEK_THURSDAY   4
  50#define MSM6242_WEEK_FRIDAY     5
  51#define MSM6242_WEEK_SATURDAY   6
  52
  53#define MSM6242_CD_30_S_ADJ     (1 << 3)        /* 30-second adjustment */
  54#define MSM6242_CD_IRQ_FLAG     (1 << 2)
  55#define MSM6242_CD_BUSY         (1 << 1)
  56#define MSM6242_CD_HOLD         (1 << 0)
  57
  58#define MSM6242_CE_T_MASK       (3 << 2)
  59#define MSM6242_CE_T_64HZ       (0 << 2)        /* period 1/64 second */
  60#define MSM6242_CE_T_1HZ        (1 << 2)        /* period 1 second */
  61#define MSM6242_CE_T_1MINUTE    (2 << 2)        /* period 1 minute */
  62#define MSM6242_CE_T_1HOUR      (3 << 2)        /* period 1 hour */
  63
  64#define MSM6242_CE_ITRPT_STND   (1 << 1)
  65#define MSM6242_CE_MASK         (1 << 0)        /* STD.P output control */
  66
  67#define MSM6242_CF_TEST         (1 << 3)
  68#define MSM6242_CF_12H          (0 << 2)
  69#define MSM6242_CF_24H          (1 << 2)
  70#define MSM6242_CF_STOP         (1 << 1)
  71#define MSM6242_CF_REST         (1 << 0)        /* reset */
  72
  73
  74struct msm6242_priv {
  75        u32 __iomem *regs;
  76        struct rtc_device *rtc;
  77};
  78
  79static inline unsigned int msm6242_read(struct msm6242_priv *priv,
  80                                       unsigned int reg)
  81{
  82        return __raw_readl(&priv->regs[reg]) & 0xf;
  83}
  84
  85static inline void msm6242_write(struct msm6242_priv *priv, unsigned int val,
  86                                unsigned int reg)
  87{
  88        __raw_writel(val, &priv->regs[reg]);
  89}
  90
  91static void msm6242_lock(struct msm6242_priv *priv)
  92{
  93        int cnt = 5;
  94
  95        msm6242_write(priv, MSM6242_CD_HOLD|MSM6242_CD_IRQ_FLAG, MSM6242_CD);
  96
  97        while ((msm6242_read(priv, MSM6242_CD) & MSM6242_CD_BUSY) && cnt) {
  98                msm6242_write(priv, MSM6242_CD_IRQ_FLAG, MSM6242_CD);
  99                udelay(70);
 100                msm6242_write(priv, MSM6242_CD_HOLD|MSM6242_CD_IRQ_FLAG, MSM6242_CD);
 101                cnt--;
 102        }
 103
 104        if (!cnt)
 105                pr_warn("timed out waiting for RTC (0x%x)\n",
 106                        msm6242_read(priv, MSM6242_CD));
 107}
 108
 109static void msm6242_unlock(struct msm6242_priv *priv)
 110{
 111        msm6242_write(priv, MSM6242_CD_IRQ_FLAG, MSM6242_CD);
 112}
 113
 114static int msm6242_read_time(struct device *dev, struct rtc_time *tm)
 115{
 116        struct msm6242_priv *priv = dev_get_drvdata(dev);
 117
 118        msm6242_lock(priv);
 119
 120        tm->tm_sec  = msm6242_read(priv, MSM6242_SECOND10) * 10 +
 121                      msm6242_read(priv, MSM6242_SECOND1);
 122        tm->tm_min  = msm6242_read(priv, MSM6242_MINUTE10) * 10 +
 123                      msm6242_read(priv, MSM6242_MINUTE1);
 124        tm->tm_hour = (msm6242_read(priv, MSM6242_HOUR10) &
 125                       MSM6242_HOUR10_HR_MASK) * 10 +
 126                      msm6242_read(priv, MSM6242_HOUR1);
 127        tm->tm_mday = msm6242_read(priv, MSM6242_DAY10) * 10 +
 128                      msm6242_read(priv, MSM6242_DAY1);
 129        tm->tm_wday = msm6242_read(priv, MSM6242_WEEK);
 130        tm->tm_mon  = msm6242_read(priv, MSM6242_MONTH10) * 10 +
 131                      msm6242_read(priv, MSM6242_MONTH1) - 1;
 132        tm->tm_year = msm6242_read(priv, MSM6242_YEAR10) * 10 +
 133                      msm6242_read(priv, MSM6242_YEAR1);
 134        if (tm->tm_year <= 69)
 135                tm->tm_year += 100;
 136
 137        if (!(msm6242_read(priv, MSM6242_CF) & MSM6242_CF_24H)) {
 138                unsigned int pm = msm6242_read(priv, MSM6242_HOUR10) &
 139                                  MSM6242_HOUR10_PM;
 140                if (!pm && tm->tm_hour == 12)
 141                        tm->tm_hour = 0;
 142                else if (pm && tm->tm_hour != 12)
 143                        tm->tm_hour += 12;
 144        }
 145
 146        msm6242_unlock(priv);
 147
 148        return 0;
 149}
 150
 151static int msm6242_set_time(struct device *dev, struct rtc_time *tm)
 152{
 153        struct msm6242_priv *priv = dev_get_drvdata(dev);
 154
 155        msm6242_lock(priv);
 156
 157        msm6242_write(priv, tm->tm_sec / 10, MSM6242_SECOND10);
 158        msm6242_write(priv, tm->tm_sec % 10, MSM6242_SECOND1);
 159        msm6242_write(priv, tm->tm_min / 10, MSM6242_MINUTE10);
 160        msm6242_write(priv, tm->tm_min % 10, MSM6242_MINUTE1);
 161        if (msm6242_read(priv, MSM6242_CF) & MSM6242_CF_24H)
 162                msm6242_write(priv, tm->tm_hour / 10, MSM6242_HOUR10);
 163        else if (tm->tm_hour >= 12)
 164                msm6242_write(priv, MSM6242_HOUR10_PM + (tm->tm_hour - 12) / 10,
 165                              MSM6242_HOUR10);
 166        else
 167                msm6242_write(priv, tm->tm_hour / 10, MSM6242_HOUR10);
 168        msm6242_write(priv, tm->tm_hour % 10, MSM6242_HOUR1);
 169        msm6242_write(priv, tm->tm_mday / 10, MSM6242_DAY10);
 170        msm6242_write(priv, tm->tm_mday % 10, MSM6242_DAY1);
 171        if (tm->tm_wday != -1)
 172                msm6242_write(priv, tm->tm_wday, MSM6242_WEEK);
 173        msm6242_write(priv, (tm->tm_mon + 1) / 10, MSM6242_MONTH10);
 174        msm6242_write(priv, (tm->tm_mon + 1) % 10, MSM6242_MONTH1);
 175        if (tm->tm_year >= 100)
 176                tm->tm_year -= 100;
 177        msm6242_write(priv, tm->tm_year / 10, MSM6242_YEAR10);
 178        msm6242_write(priv, tm->tm_year % 10, MSM6242_YEAR1);
 179
 180        msm6242_unlock(priv);
 181        return 0;
 182}
 183
 184static const struct rtc_class_ops msm6242_rtc_ops = {
 185        .read_time      = msm6242_read_time,
 186        .set_time       = msm6242_set_time,
 187};
 188
 189static int __init msm6242_rtc_probe(struct platform_device *pdev)
 190{
 191        struct resource *res;
 192        struct msm6242_priv *priv;
 193        struct rtc_device *rtc;
 194
 195        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 196        if (!res)
 197                return -ENODEV;
 198
 199        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 200        if (!priv)
 201                return -ENOMEM;
 202
 203        priv->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 204        if (!priv->regs)
 205                return -ENOMEM;
 206        platform_set_drvdata(pdev, priv);
 207
 208        rtc = devm_rtc_device_register(&pdev->dev, "rtc-msm6242",
 209                                &msm6242_rtc_ops, THIS_MODULE);
 210        if (IS_ERR(rtc))
 211                return PTR_ERR(rtc);
 212
 213        priv->rtc = rtc;
 214        return 0;
 215}
 216
 217static struct platform_driver msm6242_rtc_driver = {
 218        .driver = {
 219                .name   = "rtc-msm6242",
 220        },
 221};
 222
 223module_platform_driver_probe(msm6242_rtc_driver, msm6242_rtc_probe);
 224
 225MODULE_AUTHOR("Geert Uytterhoeven <geert@linux-m68k.org>");
 226MODULE_LICENSE("GPL");
 227MODULE_DESCRIPTION("Oki MSM6242 RTC driver");
 228MODULE_ALIAS("platform:rtc-msm6242");
 229
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