drivers/rtc/rtc-bq4802.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* rtc-bq4802.c: TI BQ4802 RTC driver.
   3  *
   4  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/io.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/rtc.h>
  13 #include <linux/bcd.h>
  14 #include <linux/slab.h>
  15
  16 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
  17 MODULE_DESCRIPTION("TI BQ4802 RTC driver");
  18 MODULE_LICENSE("GPL");
  19
  20 struct bq4802 {
  21         void __iomem            *regs;
  22         unsigned long           ioport;
  23         struct rtc_device       *rtc;
  24         spinlock_t              lock;
  25         struct resource         *r;
  26         u8 (*read)(struct bq4802 *, int);
  27         void (*write)(struct bq4802 *, int, u8);
  28 };
  29
  30 static u8 bq4802_read_io(struct bq4802 *p, int off)
  31 {
  32         return inb(p->ioport + off);
  33 }
  34
  35 static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
  36 {
  37         outb(val, p->ioport + off);
  38 }
  39
  40 static u8 bq4802_read_mem(struct bq4802 *p, int off)
  41 {
  42         return readb(p->regs + off);
  43 }
  44
  45 static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
  46 {
  47         writeb(val, p->regs + off);
  48 }
  49
  50 static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
  51 {
  52         struct bq4802 *p = dev_get_drvdata(dev);
  53         unsigned long flags;
  54         unsigned int century;
  55         u8 val;
  56
  57         spin_lock_irqsave(&p->lock, flags);
  58
  59         val = p->read(p, 0x0e);
  60         p->write(p, 0xe, val | 0x08);
  61
  62         tm->tm_sec = p->read(p, 0x00);
  63         tm->tm_min = p->read(p, 0x02);
  64         tm->tm_hour = p->read(p, 0x04);
  65         tm->tm_mday = p->read(p, 0x06);
  66         tm->tm_mon = p->read(p, 0x09);
  67         tm->tm_year = p->read(p, 0x0a);
  68         tm->tm_wday = p->read(p, 0x08);
  69         century = p->read(p, 0x0f);
  70
  71         p->write(p, 0x0e, val);
  72
  73         spin_unlock_irqrestore(&p->lock, flags);
  74
  75         tm->tm_sec = bcd2bin(tm->tm_sec);
  76         tm->tm_min = bcd2bin(tm->tm_min);
  77         tm->tm_hour = bcd2bin(tm->tm_hour);
  78         tm->tm_mday = bcd2bin(tm->tm_mday);
  79         tm->tm_mon = bcd2bin(tm->tm_mon);
  80         tm->tm_year = bcd2bin(tm->tm_year);
  81         tm->tm_wday = bcd2bin(tm->tm_wday);
  82         century = bcd2bin(century);
  83
  84         tm->tm_year += (century * 100);
  85         tm->tm_year -= 1900;
  86
  87         tm->tm_mon--;
  88
  89         return 0;
  90 }
  91
  92 static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
  93 {
  94         struct bq4802 *p = dev_get_drvdata(dev);
  95         u8 sec, min, hrs, day, mon, yrs, century, val;
  96         unsigned long flags;
  97         unsigned int year;
  98
  99         year = tm->tm_year + 1900;
 100         century = year / 100;
 101         yrs = year % 100;
 102
 103         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
 104         day = tm->tm_mday;
 105         hrs = tm->tm_hour;
 106         min = tm->tm_min;
 107         sec = tm->tm_sec;
 108
 109         sec = bin2bcd(sec);
 110         min = bin2bcd(min);
 111         hrs = bin2bcd(hrs);
 112         day = bin2bcd(day);
 113         mon = bin2bcd(mon);
 114         yrs = bin2bcd(yrs);
 115         century = bin2bcd(century);
 116
 117         spin_lock_irqsave(&p->lock, flags);
 118
 119         val = p->read(p, 0x0e);
 120         p->write(p, 0x0e, val | 0x08);
 121
 122         p->write(p, 0x00, sec);
 123         p->write(p, 0x02, min);
 124         p->write(p, 0x04, hrs);
 125         p->write(p, 0x06, day);
 126         p->write(p, 0x09, mon);
 127         p->write(p, 0x0a, yrs);
 128         p->write(p, 0x0f, century);
 129
 130         p->write(p, 0x0e, val);
 131
 132         spin_unlock_irqrestore(&p->lock, flags);
 133
 134         return 0;
 135 }
 136
 137 static const struct rtc_class_ops bq4802_ops = {
 138         .read_time      = bq4802_read_time,
 139         .set_time       = bq4802_set_time,
 140 };
 141
 142 static int bq4802_probe(struct platform_device *pdev)
 143 {
 144         struct bq4802 *p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
 145         int err = -ENOMEM;
 146
 147         if (!p)
 148                 goto out;
 149
 150         spin_lock_init(&p->lock);
 151
 152         p->r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 153         if (!p->r) {
 154                 p->r = platform_get_resource(pdev, IORESOURCE_IO, 0);
 155                 err = -EINVAL;
 156                 if (!p->r)
 157                         goto out;
 158         }
 159         if (p->r->flags & IORESOURCE_IO) {
 160                 p->ioport = p->r->start;
 161                 p->read = bq4802_read_io;
 162                 p->write = bq4802_write_io;
 163         } else if (p->r->flags & IORESOURCE_MEM) {
 164                 p->regs = devm_ioremap(&pdev->dev, p->r->start,
 165                                         resource_size(p->r));
 166                 if (!p->regs){
 167                         err = -ENOMEM;
 168                         goto out;
 169                 }
 170                 p->read = bq4802_read_mem;
 171                 p->write = bq4802_write_mem;
 172         } else {
 173                 err = -EINVAL;
 174                 goto out;
 175         }
 176
 177         platform_set_drvdata(pdev, p);
 178
 179         p->rtc = devm_rtc_device_register(&pdev->dev, "bq4802",
 180                                         &bq4802_ops, THIS_MODULE);
 181         if (IS_ERR(p->rtc)) {
 182                 err = PTR_ERR(p->rtc);
 183                 goto out;
 184         }
 185
 186         err = 0;
 187 out:
 188         return err;
 189
 190 }
 191
 192 /* work with hotplug and coldplug */
 193 MODULE_ALIAS("platform:rtc-bq4802");
 194
 195 static struct platform_driver bq4802_driver = {
 196         .driver         = {
 197                 .name   = "rtc-bq4802",
 198         },
 199         .probe          = bq4802_probe,
 200 };
 201
 202 module_platform_driver(bq4802_driver);