diff options
author | Robert Coulson <rob.coulson@gmail.com> | 2013-05-16 18:10:41 -0400 |
---|---|---|
committer | Guenter Roeck <linux@roeck-us.net> | 2013-06-27 13:29:02 -0400 |
commit | 79c1cc1c90c0ccaddd20965ea19205c54addd5f7 (patch) | |
tree | 0a1de32d3c503e2eaf56130a315b9753530f3b68 /Documentation/hwmon | |
parent | 3a8fe3315571e896489d2e271ffe7f935bfc5ce8 (diff) |
hwmon: (ds1621) Add ds1631 chip support to ds1621 driver and documentation
Add definitions, information, and code for ds1631 chip support
to the ds1621 driver.
Signed-off-by: Robert Coulson <rob.coulson@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'Documentation/hwmon')
-rw-r--r-- | Documentation/hwmon/ds1621 | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/Documentation/hwmon/ds1621 b/Documentation/hwmon/ds1621 index b61e77c6b1cb..1ebaa2485770 100644 --- a/Documentation/hwmon/ds1621 +++ b/Documentation/hwmon/ds1621 | |||
@@ -14,6 +14,11 @@ Supported chips: | |||
14 | Addresses scanned: I2C 0x48 - 0x4f | 14 | Addresses scanned: I2C 0x48 - 0x4f |
15 | Datasheet: Publicly available from www.datasheetarchive.com | 15 | Datasheet: Publicly available from www.datasheetarchive.com |
16 | 16 | ||
17 | * Maxim Integrated DS1631 | ||
18 | Prefix: 'ds1631' | ||
19 | Addresses scanned: I2C 0x48 - 0x4f | ||
20 | Datasheet: Publicly available from www.maximintegrated.com | ||
21 | |||
17 | * Maxim Integrated DS1721 | 22 | * Maxim Integrated DS1721 |
18 | Prefix: 'ds1721' | 23 | Prefix: 'ds1721' |
19 | Addresses scanned: I2C 0x48 - 0x4f | 24 | Addresses scanned: I2C 0x48 - 0x4f |
@@ -69,7 +74,15 @@ Temperature conversion of the DS1621 takes up to 1000ms; internal access to | |||
69 | non-volatile registers may last for 10ms or below. | 74 | non-volatile registers may last for 10ms or below. |
70 | 75 | ||
71 | The DS1625 is pin compatible and functionally equivalent with the DS1621, | 76 | The DS1625 is pin compatible and functionally equivalent with the DS1621, |
72 | but the DS1621 is meant to replace it. | 77 | but the DS1621 is meant to replace it. The DS1631 and DS1721 are also |
78 | pin compatible with the DS1621, but provide multi-resolution support. | ||
79 | |||
80 | Since there is no version register, there is no unique identification | ||
81 | for these devices. In addition, the DS1631 and DS1721 will emulate a | ||
82 | DS1621 device, if not explicitly instantiated (why? because the detect | ||
83 | function compares the temperature register values bits and checks for a | ||
84 | 9-bit resolution). Therefore, for correct device identification and | ||
85 | functionality, explicit device instantiation is required. | ||
73 | 86 | ||
74 | The DS1721 is pin compatible with the DS1621, has an accuracy of +/- 1.0 | 87 | The DS1721 is pin compatible with the DS1621, has an accuracy of +/- 1.0 |
75 | degree Celsius over a -10 to +85 degree range, a minimum/maximum alarm | 88 | degree Celsius over a -10 to +85 degree range, a minimum/maximum alarm |
@@ -78,9 +91,17 @@ time of 750ms. | |||
78 | 91 | ||
79 | In addition, the DS1721 supports four resolution settings from 9 to 12 bits | 92 | In addition, the DS1721 supports four resolution settings from 9 to 12 bits |
80 | (defined in degrees C per LSB: 0.5, 0.25, 0.125, and 0.0625, respectifully), | 93 | (defined in degrees C per LSB: 0.5, 0.25, 0.125, and 0.0625, respectifully), |
81 | that are set at device power on to the highest resolution: 12-bits (0.0625 degree C). | 94 | that are set at device power on to the highest resolution: 12-bits. |
95 | |||
96 | One additional note about the ds1721 is that although the data sheet says | ||
97 | the temperature flags (THF and TLF) are used internally, these flags do | ||
98 | get set and cleared as the actual temperature crosses the min or max settings. | ||
99 | |||
100 | The DS1631 is also pin compatible with the DS1621 and feature compatible with | ||
101 | the DS1721, however the DS1631 accuracy is +/- 0.5 degree Celsius over the | ||
102 | same range. | ||
82 | 103 | ||
83 | Changing the DS1721 resolution mode affects the conversion time and can be | 104 | Changing the DS1631/1721 resolution mode affects the conversion time and can be |
84 | done from userspace, via the device 'update_interval' sysfs attribute. This | 105 | done from userspace, via the device 'update_interval' sysfs attribute. This |
85 | attribute will normalize range of input values to the device maximum resolution | 106 | attribute will normalize range of input values to the device maximum resolution |
86 | values defined in the datasheet as such: | 107 | values defined in the datasheet as such: |