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Commit | Line | Data |
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40313dc0 GKH |
1 | From stable-bounces@linux.kernel.org Sat Feb 3 06:18:09 2007 |
2 | From: Atsushi Nemoto <anemo@mba.ocn.ne.jp> | |
3 | Date: Sat, 03 Feb 2007 23:16:36 +0900 (JST) | |
4 | Subject: rtc-pcf8563: detect polarity of century bit automatically | |
5 | To: akpm@linux-foundation.org | |
6 | Cc: jean-baptiste.maneyrol@teamlog.com, a.zummo@towertech.it, dbrownell@users.sourceforge.net, torvalds@linux-foundation.org, stable@kernel.org | |
7 | Message-ID: <20070203.231636.41198366.anemo@mba.ocn.ne.jp> | |
8 | ||
9 | ||
10 | From: Atsushi Nemoto <anemo@mba.ocn.ne.jp> | |
11 | ||
12 | The usage of the century bit was inverted on 2.6.19 following to PCF8563's | |
13 | description, but it was not match to usage suggested by RTC8564's | |
14 | datasheet. Anyway what MO_C=1 means can vary on each platform. This patch | |
15 | is to detect its polarity in get_datetime routine. The default value of | |
16 | c_polarity is 0 (MO_C=1 means 19xx) so that this patch does not change | |
17 | current behavior even if get_datetime was not called before set_datetime. | |
18 | ||
19 | Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> | |
20 | Cc: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@teamlog.com> | |
21 | Cc: David Brownell <dbrownell@users.sourceforge.net> | |
22 | Cc: Alessandro Zummo <a.zummo@towertech.it> | |
23 | Signed-off-by: Andrew Morton <akpm@linux-foundation.org> | |
24 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | |
25 | ||
26 | --- | |
27 | drivers/rtc/rtc-pcf8563.c | 40 ++++++++++++++++++++++++++++++++++------ | |
28 | 1 file changed, 34 insertions(+), 6 deletions(-) | |
29 | ||
30 | --- linux-2.6.20.1.orig/drivers/rtc/rtc-pcf8563.c | |
31 | +++ linux-2.6.20.1/drivers/rtc/rtc-pcf8563.c | |
32 | @@ -53,6 +53,25 @@ I2C_CLIENT_INSMOD; | |
33 | #define PCF8563_SC_LV 0x80 /* low voltage */ | |
34 | #define PCF8563_MO_C 0x80 /* century */ | |
35 | ||
36 | +struct pcf8563 { | |
37 | + struct i2c_client client; | |
38 | + /* | |
39 | + * The meaning of MO_C bit varies by the chip type. | |
40 | + * From PCF8563 datasheet: this bit is toggled when the years | |
41 | + * register overflows from 99 to 00 | |
42 | + * 0 indicates the century is 20xx | |
43 | + * 1 indicates the century is 19xx | |
44 | + * From RTC8564 datasheet: this bit indicates change of | |
45 | + * century. When the year digit data overflows from 99 to 00, | |
46 | + * this bit is set. By presetting it to 0 while still in the | |
47 | + * 20th century, it will be set in year 2000, ... | |
48 | + * There seems no reliable way to know how the system use this | |
49 | + * bit. So let's do it heuristically, assuming we are live in | |
50 | + * 1970...2069. | |
51 | + */ | |
52 | + int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */ | |
53 | +}; | |
54 | + | |
55 | static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind); | |
56 | static int pcf8563_detach(struct i2c_client *client); | |
57 | ||
58 | @@ -62,6 +81,7 @@ static int pcf8563_detach(struct i2c_cli | |
59 | */ | |
60 | static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
61 | { | |
62 | + struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client); | |
63 | unsigned char buf[13] = { PCF8563_REG_ST1 }; | |
64 | ||
65 | struct i2c_msg msgs[] = { | |
66 | @@ -94,8 +114,12 @@ static int pcf8563_get_datetime(struct i | |
67 | tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F); | |
68 | tm->tm_wday = buf[PCF8563_REG_DW] & 0x07; | |
69 | tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ | |
70 | - tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]) | |
71 | - + (buf[PCF8563_REG_MO] & PCF8563_MO_C ? 0 : 100); | |
72 | + tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]); | |
73 | + if (tm->tm_year < 70) | |
74 | + tm->tm_year += 100; /* assume we are in 1970...2069 */ | |
75 | + /* detect the polarity heuristically. see note above. */ | |
76 | + pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ? | |
77 | + (tm->tm_year >= 100) : (tm->tm_year < 100); | |
78 | ||
79 | dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " | |
80 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
81 | @@ -114,6 +138,7 @@ static int pcf8563_get_datetime(struct i | |
82 | ||
83 | static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
84 | { | |
85 | + struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client); | |
86 | int i, err; | |
87 | unsigned char buf[9]; | |
88 | ||
89 | @@ -135,7 +160,7 @@ static int pcf8563_set_datetime(struct i | |
90 | ||
91 | /* year and century */ | |
92 | buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100); | |
93 | - if (tm->tm_year < 100) | |
94 | + if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100)) | |
95 | buf[PCF8563_REG_MO] |= PCF8563_MO_C; | |
96 | ||
97 | buf[PCF8563_REG_DW] = tm->tm_wday & 0x07; | |
98 | @@ -248,6 +273,7 @@ static struct i2c_driver pcf8563_driver | |
99 | ||
100 | static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind) | |
101 | { | |
102 | + struct pcf8563 *pcf8563; | |
103 | struct i2c_client *client; | |
104 | struct rtc_device *rtc; | |
105 | ||
106 | @@ -260,11 +286,12 @@ static int pcf8563_probe(struct i2c_adap | |
107 | goto exit; | |
108 | } | |
109 | ||
110 | - if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) { | |
111 | + if (!(pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL))) { | |
112 | err = -ENOMEM; | |
113 | goto exit; | |
114 | } | |
115 | ||
116 | + client = &pcf8563->client; | |
117 | client->addr = address; | |
118 | client->driver = &pcf8563_driver; | |
119 | client->adapter = adapter; | |
120 | @@ -301,7 +328,7 @@ exit_detach: | |
121 | i2c_detach_client(client); | |
122 | ||
123 | exit_kfree: | |
124 | - kfree(client); | |
125 | + kfree(pcf8563); | |
126 | ||
127 | exit: | |
128 | return err; | |
129 | @@ -309,6 +336,7 @@ exit: | |
130 | ||
131 | static int pcf8563_detach(struct i2c_client *client) | |
132 | { | |
133 | + struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client); | |
134 | int err; | |
135 | struct rtc_device *rtc = i2c_get_clientdata(client); | |
136 | ||
137 | @@ -318,7 +346,7 @@ static int pcf8563_detach(struct i2c_cli | |
138 | if ((err = i2c_detach_client(client))) | |
139 | return err; | |
140 | ||
141 | - kfree(client); | |
142 | + kfree(pcf8563); | |
143 | ||
144 | return 0; | |
145 | } |