drivers/rtc/rtc-bq4802.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /* rtc-bq4802.c: TI BQ4802 RTC driver.
0003  *
0004  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
0005  */
0006
0007 #include <linux/kernel.h>
0008 #include <linux/module.h>
0009 #include <linux/init.h>
0010 #include <linux/io.h>
0011 #include <linux/platform_device.h>
0012 #include <linux/rtc.h>
0013 #include <linux/bcd.h>
0014 #include <linux/slab.h>
0015
0016 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
0017 MODULE_DESCRIPTION("TI BQ4802 RTC driver");
0018 MODULE_LICENSE("GPL");
0019
0020 struct bq4802 {
0021     void __iomem        *regs;
0022     unsigned long       ioport;
0023     struct rtc_device   *rtc;
0024     spinlock_t      lock;
0025     struct resource     *r;
0026     u8 (*read)(struct bq4802 *, int);
0027     void (*write)(struct bq4802 *, int, u8);
0028 };
0029
0030 static u8 bq4802_read_io(struct bq4802 *p, int off)
0031 {
0032     return inb(p->ioport + off);
0033 }
0034
0035 static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
0036 {
0037     outb(val, p->ioport + off);
0038 }
0039
0040 static u8 bq4802_read_mem(struct bq4802 *p, int off)
0041 {
0042     return readb(p->regs + off);
0043 }
0044
0045 static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
0046 {
0047     writeb(val, p->regs + off);
0048 }
0049
0050 static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
0051 {
0052     struct bq4802 *p = dev_get_drvdata(dev);
0053     unsigned long flags;
0054     unsigned int century;
0055     u8 val;
0056
0057     spin_lock_irqsave(&p->lock, flags);
0058
0059     val = p->read(p, 0x0e);
0060     p->write(p, 0xe, val | 0x08);
0061
0062     tm->tm_sec = p->read(p, 0x00);
0063     tm->tm_min = p->read(p, 0x02);
0064     tm->tm_hour = p->read(p, 0x04);
0065     tm->tm_mday = p->read(p, 0x06);
0066     tm->tm_mon = p->read(p, 0x09);
0067     tm->tm_year = p->read(p, 0x0a);
0068     tm->tm_wday = p->read(p, 0x08);
0069     century = p->read(p, 0x0f);
0070
0071     p->write(p, 0x0e, val);
0072
0073     spin_unlock_irqrestore(&p->lock, flags);
0074
0075     tm->tm_sec = bcd2bin(tm->tm_sec);
0076     tm->tm_min = bcd2bin(tm->tm_min);
0077     tm->tm_hour = bcd2bin(tm->tm_hour);
0078     tm->tm_mday = bcd2bin(tm->tm_mday);
0079     tm->tm_mon = bcd2bin(tm->tm_mon);
0080     tm->tm_year = bcd2bin(tm->tm_year);
0081     tm->tm_wday = bcd2bin(tm->tm_wday);
0082     century = bcd2bin(century);
0083
0084     tm->tm_year += (century * 100);
0085     tm->tm_year -= 1900;
0086
0087     tm->tm_mon--;
0088
0089     return 0;
0090 }
0091
0092 static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
0093 {
0094     struct bq4802 *p = dev_get_drvdata(dev);
0095     u8 sec, min, hrs, day, mon, yrs, century, val;
0096     unsigned long flags;
0097     unsigned int year;
0098
0099     year = tm->tm_year + 1900;
0100     century = year / 100;
0101     yrs = year % 100;
0102
0103     mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
0104     day = tm->tm_mday;
0105     hrs = tm->tm_hour;
0106     min = tm->tm_min;
0107     sec = tm->tm_sec;
0108
0109     sec = bin2bcd(sec);
0110     min = bin2bcd(min);
0111     hrs = bin2bcd(hrs);
0112     day = bin2bcd(day);
0113     mon = bin2bcd(mon);
0114     yrs = bin2bcd(yrs);
0115     century = bin2bcd(century);
0116
0117     spin_lock_irqsave(&p->lock, flags);
0118
0119     val = p->read(p, 0x0e);
0120     p->write(p, 0x0e, val | 0x08);
0121
0122     p->write(p, 0x00, sec);
0123     p->write(p, 0x02, min);
0124     p->write(p, 0x04, hrs);
0125     p->write(p, 0x06, day);
0126     p->write(p, 0x09, mon);
0127     p->write(p, 0x0a, yrs);
0128     p->write(p, 0x0f, century);
0129
0130     p->write(p, 0x0e, val);
0131
0132     spin_unlock_irqrestore(&p->lock, flags);
0133
0134     return 0;
0135 }
0136
0137 static const struct rtc_class_ops bq4802_ops = {
0138     .read_time  = bq4802_read_time,
0139     .set_time   = bq4802_set_time,
0140 };
0141
0142 static int bq4802_probe(struct platform_device *pdev)
0143 {
0144     struct bq4802 *p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
0145     int err = -ENOMEM;
0146
0147     if (!p)
0148         goto out;
0149
0150     spin_lock_init(&p->lock);
0151
0152     p->r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
0153     if (!p->r) {
0154         p->r = platform_get_resource(pdev, IORESOURCE_IO, 0);
0155         err = -EINVAL;
0156         if (!p->r)
0157             goto out;
0158     }
0159     if (p->r->flags & IORESOURCE_IO) {
0160         p->ioport = p->r->start;
0161         p->read = bq4802_read_io;
0162         p->write = bq4802_write_io;
0163     } else if (p->r->flags & IORESOURCE_MEM) {
0164         p->regs = devm_ioremap(&pdev->dev, p->r->start,
0165                     resource_size(p->r));
0166         if (!p->regs){
0167             err = -ENOMEM;
0168             goto out;
0169         }
0170         p->read = bq4802_read_mem;
0171         p->write = bq4802_write_mem;
0172     } else {
0173         err = -EINVAL;
0174         goto out;
0175     }
0176
0177     platform_set_drvdata(pdev, p);
0178
0179     p->rtc = devm_rtc_device_register(&pdev->dev, "bq4802",
0180                     &bq4802_ops, THIS_MODULE);
0181     if (IS_ERR(p->rtc)) {
0182         err = PTR_ERR(p->rtc);
0183         goto out;
0184     }
0185
0186     err = 0;
0187 out:
0188     return err;
0189
0190 }
0191
0192 /* work with hotplug and coldplug */
0193 MODULE_ALIAS("platform:rtc-bq4802");
0194
0195 static struct platform_driver bq4802_driver = {
0196     .driver     = {
0197         .name   = "rtc-bq4802",
0198     },
0199     .probe      = bq4802_probe,
0200 };
0201
0202 module_platform_driver(bq4802_driver);