2 * Dallas DS1216 RTC driver
4 * Copyright (c) 2007 Thomas Bogendoerfer
8 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/bcd.h>
12 #include <linux/slab.h>
14 #define DRV_VERSION "0.2"
27 #define DS1216_HOUR_1224 (1 << 7)
28 #define DS1216_HOUR_AMPM (1 << 5)
31 struct rtc_device
*rtc
;
35 static const u8 magic
[] = {
36 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
40 * Read the 64 bit we'd like to have - It a series
41 * of 64 bits showing up in the LSB of the base register.
44 static void ds1216_read(u8 __iomem
*ioaddr
, u8
*buf
)
49 for (i
= 0; i
< 8; i
++) {
51 for (j
= 0; j
< 8; j
++)
52 c
|= (readb(ioaddr
) & 0x1) << j
;
57 static void ds1216_write(u8 __iomem
*ioaddr
, const u8
*buf
)
62 for (i
= 0; i
< 8; i
++) {
64 for (j
= 0; j
< 8; j
++) {
71 static void ds1216_switch_ds_to_clock(u8 __iomem
*ioaddr
)
73 /* Reset magic pointer */
75 /* Write 64 bit magic to DS1216 */
76 ds1216_write(ioaddr
, magic
);
79 static int ds1216_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
81 struct platform_device
*pdev
= to_platform_device(dev
);
82 struct ds1216_priv
*priv
= platform_get_drvdata(pdev
);
83 struct ds1216_regs regs
;
85 ds1216_switch_ds_to_clock(priv
->ioaddr
);
86 ds1216_read(priv
->ioaddr
, (u8
*)®s
);
88 tm
->tm_sec
= bcd2bin(regs
.sec
);
89 tm
->tm_min
= bcd2bin(regs
.min
);
90 if (regs
.hour
& DS1216_HOUR_1224
) {
92 tm
->tm_hour
= bcd2bin(regs
.hour
& 0x1f);
93 if (regs
.hour
& DS1216_HOUR_AMPM
)
96 tm
->tm_hour
= bcd2bin(regs
.hour
& 0x3f);
97 tm
->tm_wday
= (regs
.wday
& 7) - 1;
98 tm
->tm_mday
= bcd2bin(regs
.mday
& 0x3f);
99 tm
->tm_mon
= bcd2bin(regs
.month
& 0x1f);
100 tm
->tm_year
= bcd2bin(regs
.year
);
101 if (tm
->tm_year
< 70)
104 return rtc_valid_tm(tm
);
107 static int ds1216_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
109 struct platform_device
*pdev
= to_platform_device(dev
);
110 struct ds1216_priv
*priv
= platform_get_drvdata(pdev
);
111 struct ds1216_regs regs
;
113 ds1216_switch_ds_to_clock(priv
->ioaddr
);
114 ds1216_read(priv
->ioaddr
, (u8
*)®s
);
116 regs
.tsec
= 0; /* clear 0.1 and 0.01 seconds */
117 regs
.sec
= bin2bcd(tm
->tm_sec
);
118 regs
.min
= bin2bcd(tm
->tm_min
);
119 regs
.hour
&= DS1216_HOUR_1224
;
120 if (regs
.hour
&& tm
->tm_hour
> 12) {
121 regs
.hour
|= DS1216_HOUR_AMPM
;
124 regs
.hour
|= bin2bcd(tm
->tm_hour
);
126 regs
.wday
|= tm
->tm_wday
;
127 regs
.mday
= bin2bcd(tm
->tm_mday
);
128 regs
.month
= bin2bcd(tm
->tm_mon
);
129 regs
.year
= bin2bcd(tm
->tm_year
% 100);
131 ds1216_switch_ds_to_clock(priv
->ioaddr
);
132 ds1216_write(priv
->ioaddr
, (u8
*)®s
);
136 static const struct rtc_class_ops ds1216_rtc_ops
= {
137 .read_time
= ds1216_rtc_read_time
,
138 .set_time
= ds1216_rtc_set_time
,
141 static int __init
ds1216_rtc_probe(struct platform_device
*pdev
)
143 struct resource
*res
;
144 struct ds1216_priv
*priv
;
147 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
150 priv
= devm_kzalloc(&pdev
->dev
, sizeof(*priv
), GFP_KERNEL
);
154 platform_set_drvdata(pdev
, priv
);
156 priv
->ioaddr
= devm_ioremap_resource(&pdev
->dev
, res
);
157 if (IS_ERR(priv
->ioaddr
))
158 return PTR_ERR(priv
->ioaddr
);
160 priv
->rtc
= devm_rtc_device_register(&pdev
->dev
, "ds1216",
161 &ds1216_rtc_ops
, THIS_MODULE
);
162 if (IS_ERR(priv
->rtc
))
163 return PTR_ERR(priv
->rtc
);
165 /* dummy read to get clock into a known state */
166 ds1216_read(priv
->ioaddr
, dummy
);
170 static struct platform_driver ds1216_rtc_platform_driver
= {
172 .name
= "rtc-ds1216",
173 .owner
= THIS_MODULE
,
177 module_platform_driver_probe(ds1216_rtc_platform_driver
, ds1216_rtc_probe
);
179 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
180 MODULE_DESCRIPTION("DS1216 RTC driver");
181 MODULE_LICENSE("GPL");
182 MODULE_VERSION(DRV_VERSION
);
183 MODULE_ALIAS("platform:rtc-ds1216");