drivers/rtc/rtc-tx4939.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * TX4939 internal RTC driver
   4  * Based on RBTX49xx patch from CELF patch archive.
   5  *
   6  * (C) Copyright TOSHIBA CORPORATION 2005-2007
   7  */
   8 #include <linux/rtc.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/module.h>
  12 #include <linux/io.h>
  13 #include <linux/gfp.h>
  14
  15 #define TX4939_RTCCTL_ALME      0x00000080
  16 #define TX4939_RTCCTL_ALMD      0x00000040
  17 #define TX4939_RTCCTL_BUSY      0x00000020
  18
  19 #define TX4939_RTCCTL_COMMAND   0x00000007
  20 #define TX4939_RTCCTL_COMMAND_NOP       0x00000000
  21 #define TX4939_RTCCTL_COMMAND_GETTIME   0x00000001
  22 #define TX4939_RTCCTL_COMMAND_SETTIME   0x00000002
  23 #define TX4939_RTCCTL_COMMAND_GETALARM  0x00000003
  24 #define TX4939_RTCCTL_COMMAND_SETALARM  0x00000004
  25
  26 #define TX4939_RTCTBC_PM        0x00000080
  27 #define TX4939_RTCTBC_COMP      0x0000007f
  28
  29 #define TX4939_RTC_REG_RAMSIZE  0x00000100
  30 #define TX4939_RTC_REG_RWBSIZE  0x00000006
  31
  32 struct tx4939_rtc_reg {
  33         __u32 ctl;
  34         __u32 adr;
  35         __u32 dat;
  36         __u32 tbc;
  37 };
  38
  39 struct tx4939rtc_plat_data {
  40         struct rtc_device *rtc;
  41         struct tx4939_rtc_reg __iomem *rtcreg;
  42         spinlock_t lock;
  43 };
  44
  45 static int tx4939_rtc_cmd(struct tx4939_rtc_reg __iomem *rtcreg, int cmd)
  46 {
  47         int i = 0;
  48
  49         __raw_writel(cmd, &rtcreg->ctl);
  50         /* This might take 30us (next 32.768KHz clock) */
  51         while (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_BUSY) {
  52                 /* timeout on approx. 100us (@ GBUS200MHz) */
  53                 if (i++ > 200 * 100)
  54                         return -EBUSY;
  55                 cpu_relax();
  56         }
  57         return 0;
  58 }
  59
  60 static int tx4939_rtc_set_time(struct device *dev, struct rtc_time *tm)
  61 {
  62         struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
  63         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  64         unsigned long secs = rtc_tm_to_time64(tm);
  65         int i, ret;
  66         unsigned char buf[6];
  67
  68         buf[0] = 0;
  69         buf[1] = 0;
  70         buf[2] = secs;
  71         buf[3] = secs >> 8;
  72         buf[4] = secs >> 16;
  73         buf[5] = secs >> 24;
  74         spin_lock_irq(&pdata->lock);
  75         __raw_writel(0, &rtcreg->adr);
  76         for (i = 0; i < 6; i++)
  77                 __raw_writel(buf[i], &rtcreg->dat);
  78         ret = tx4939_rtc_cmd(rtcreg,
  79                              TX4939_RTCCTL_COMMAND_SETTIME |
  80                              (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
  81         spin_unlock_irq(&pdata->lock);
  82         return ret;
  83 }
  84
  85 static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm)
  86 {
  87         struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
  88         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  89         int i, ret;
  90         unsigned long sec;
  91         unsigned char buf[6];
  92
  93         spin_lock_irq(&pdata->lock);
  94         ret = tx4939_rtc_cmd(rtcreg,
  95                              TX4939_RTCCTL_COMMAND_GETTIME |
  96                              (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
  97         if (ret) {
  98                 spin_unlock_irq(&pdata->lock);
  99                 return ret;
 100         }
 101         __raw_writel(2, &rtcreg->adr);
 102         for (i = 2; i < 6; i++)
 103                 buf[i] = __raw_readl(&rtcreg->dat);
 104         spin_unlock_irq(&pdata->lock);
 105         sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
 106                 (buf[3] << 8) | buf[2];
 107         rtc_time64_to_tm(sec, tm);
 108         return 0;
 109 }
 110
 111 static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 112 {
 113         struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
 114         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 115         int i, ret;
 116         unsigned long sec;
 117         unsigned char buf[6];
 118
 119         sec = rtc_tm_to_time64(&alrm->time);
 120         buf[0] = 0;
 121         buf[1] = 0;
 122         buf[2] = sec;
 123         buf[3] = sec >> 8;
 124         buf[4] = sec >> 16;
 125         buf[5] = sec >> 24;
 126         spin_lock_irq(&pdata->lock);
 127         __raw_writel(0, &rtcreg->adr);
 128         for (i = 0; i < 6; i++)
 129                 __raw_writel(buf[i], &rtcreg->dat);
 130         ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |
 131                              (alrm->enabled ? TX4939_RTCCTL_ALME : 0));
 132         spin_unlock_irq(&pdata->lock);
 133         return ret;
 134 }
 135
 136 static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 137 {
 138         struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
 139         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 140         int i, ret;
 141         unsigned long sec;
 142         unsigned char buf[6];
 143         u32 ctl;
 144
 145         spin_lock_irq(&pdata->lock);
 146         ret = tx4939_rtc_cmd(rtcreg,
 147                              TX4939_RTCCTL_COMMAND_GETALARM |
 148                              (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
 149         if (ret) {
 150                 spin_unlock_irq(&pdata->lock);
 151                 return ret;
 152         }
 153         __raw_writel(2, &rtcreg->adr);
 154         for (i = 2; i < 6; i++)
 155                 buf[i] = __raw_readl(&rtcreg->dat);
 156         ctl = __raw_readl(&rtcreg->ctl);
 157         alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;
 158         alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;
 159         spin_unlock_irq(&pdata->lock);
 160         sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
 161                 (buf[3] << 8) | buf[2];
 162         rtc_time64_to_tm(sec, &alrm->time);
 163         return rtc_valid_tm(&alrm->time);
 164 }
 165
 166 static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 167 {
 168         struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev);
 169
 170         spin_lock_irq(&pdata->lock);
 171         tx4939_rtc_cmd(pdata->rtcreg,
 172                        TX4939_RTCCTL_COMMAND_NOP |
 173                        (enabled ? TX4939_RTCCTL_ALME : 0));
 174         spin_unlock_irq(&pdata->lock);
 175         return 0;
 176 }
 177
 178 static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
 179 {
 180         struct tx4939rtc_plat_data *pdata = dev_get_drvdata(dev_id);
 181         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 182         unsigned long events = RTC_IRQF;
 183
 184         spin_lock(&pdata->lock);
 185         if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {
 186                 events |= RTC_AF;
 187                 tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
 188         }
 189         spin_unlock(&pdata->lock);
 190         rtc_update_irq(pdata->rtc, 1, events);
 191
 192         return IRQ_HANDLED;
 193 }
 194
 195 static const struct rtc_class_ops tx4939_rtc_ops = {
 196         .read_time              = tx4939_rtc_read_time,
 197         .read_alarm             = tx4939_rtc_read_alarm,
 198         .set_alarm              = tx4939_rtc_set_alarm,
 199         .set_time               = tx4939_rtc_set_time,
 200         .alarm_irq_enable       = tx4939_rtc_alarm_irq_enable,
 201 };
 202
 203 static int tx4939_nvram_read(void *priv, unsigned int pos, void *val,
 204                              size_t bytes)
 205 {
 206         struct tx4939rtc_plat_data *pdata = priv;
 207         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 208         u8 *buf = val;
 209
 210         spin_lock_irq(&pdata->lock);
 211         for (; bytes; bytes--) {
 212                 __raw_writel(pos++, &rtcreg->adr);
 213                 *buf++ = __raw_readl(&rtcreg->dat);
 214         }
 215         spin_unlock_irq(&pdata->lock);
 216         return 0;
 217 }
 218
 219 static int tx4939_nvram_write(void *priv, unsigned int pos, void *val,
 220                               size_t bytes)
 221 {
 222         struct tx4939rtc_plat_data *pdata = priv;
 223         struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 224         u8 *buf = val;
 225
 226         spin_lock_irq(&pdata->lock);
 227         for (; bytes; bytes--) {
 228                 __raw_writel(pos++, &rtcreg->adr);
 229                 __raw_writel(*buf++, &rtcreg->dat);
 230         }
 231         spin_unlock_irq(&pdata->lock);
 232         return 0;
 233 }
 234
 235 static int __init tx4939_rtc_probe(struct platform_device *pdev)
 236 {
 237         struct rtc_device *rtc;
 238         struct tx4939rtc_plat_data *pdata;
 239         int irq, ret;
 240         struct nvmem_config nvmem_cfg = {
 241                 .name = "tx4939_nvram",
 242                 .size = TX4939_RTC_REG_RAMSIZE,
 243                 .reg_read = tx4939_nvram_read,
 244                 .reg_write = tx4939_nvram_write,
 245         };
 246
 247         irq = platform_get_irq(pdev, 0);
 248         if (irq < 0)
 249                 return -ENODEV;
 250         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 251         if (!pdata)
 252                 return -ENOMEM;
 253         platform_set_drvdata(pdev, pdata);
 254
 255         pdata->rtcreg = devm_platform_ioremap_resource(pdev, 0);
 256         if (IS_ERR(pdata->rtcreg))
 257                 return PTR_ERR(pdata->rtcreg);
 258
 259         spin_lock_init(&pdata->lock);
 260         tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
 261         if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
 262                              0, pdev->name, &pdev->dev) < 0)
 263                 return -EBUSY;
 264         rtc = devm_rtc_allocate_device(&pdev->dev);
 265         if (IS_ERR(rtc))
 266                 return PTR_ERR(rtc);
 267
 268         rtc->ops = &tx4939_rtc_ops;
 269         rtc->nvram_old_abi = true;
 270         rtc->range_max = U32_MAX;
 271
 272         pdata->rtc = rtc;
 273
 274         nvmem_cfg.priv = pdata;
 275         ret = rtc_nvmem_register(rtc, &nvmem_cfg);
 276         if (ret)
 277                 return ret;
 278
 279         return rtc_register_device(rtc);
 280 }
 281
 282 static int __exit tx4939_rtc_remove(struct platform_device *pdev)
 283 {
 284         struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
 285
 286         spin_lock_irq(&pdata->lock);
 287         tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
 288         spin_unlock_irq(&pdata->lock);
 289         return 0;
 290 }
 291
 292 static struct platform_driver tx4939_rtc_driver = {
 293         .remove         = __exit_p(tx4939_rtc_remove),
 294         .driver         = {
 295                 .name   = "tx4939rtc",
 296         },
 297 };
 298
 299 module_platform_driver_probe(tx4939_rtc_driver, tx4939_rtc_probe);
 300
 301 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 302 MODULE_DESCRIPTION("TX4939 internal RTC driver");
 303 MODULE_LICENSE("GPL v2");
 304 MODULE_ALIAS("platform:tx4939rtc");