drivers/rtc/rtc-bq4802.c

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