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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>
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Robert Coulson
Guenter Roeck
parent
3a8fe33155
commit
79c1cc1c90
@ -14,6 +14,11 @@ Supported chips:
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Addresses scanned: I2C 0x48 - 0x4f
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Datasheet: Publicly available from www.datasheetarchive.com
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* Maxim Integrated DS1631
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Prefix: 'ds1631'
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Addresses scanned: I2C 0x48 - 0x4f
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Datasheet: Publicly available from www.maximintegrated.com
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* Maxim Integrated DS1721
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Prefix: 'ds1721'
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Addresses scanned: I2C 0x48 - 0x4f
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@ -69,7 +74,15 @@ Temperature conversion of the DS1621 takes up to 1000ms; internal access to
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non-volatile registers may last for 10ms or below.
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The DS1625 is pin compatible and functionally equivalent with the DS1621,
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but the DS1621 is meant to replace it.
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but the DS1621 is meant to replace it. The DS1631 and DS1721 are also
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pin compatible with the DS1621, but provide multi-resolution support.
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Since there is no version register, there is no unique identification
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for these devices. In addition, the DS1631 and DS1721 will emulate a
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DS1621 device, if not explicitly instantiated (why? because the detect
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function compares the temperature register values bits and checks for a
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9-bit resolution). Therefore, for correct device identification and
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functionality, explicit device instantiation is required.
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The DS1721 is pin compatible with the DS1621, has an accuracy of +/- 1.0
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degree Celsius over a -10 to +85 degree range, a minimum/maximum alarm
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@ -78,9 +91,17 @@ time of 750ms.
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In addition, the DS1721 supports four resolution settings from 9 to 12 bits
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(defined in degrees C per LSB: 0.5, 0.25, 0.125, and 0.0625, respectifully),
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that are set at device power on to the highest resolution: 12-bits (0.0625 degree C).
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that are set at device power on to the highest resolution: 12-bits.
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Changing the DS1721 resolution mode affects the conversion time and can be
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One additional note about the ds1721 is that although the data sheet says
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the temperature flags (THF and TLF) are used internally, these flags do
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get set and cleared as the actual temperature crosses the min or max settings.
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The DS1631 is also pin compatible with the DS1621 and feature compatible with
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the DS1721, however the DS1631 accuracy is +/- 0.5 degree Celsius over the
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same range.
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Changing the DS1631/1721 resolution mode affects the conversion time and can be
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done from userspace, via the device 'update_interval' sysfs attribute. This
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attribute will normalize range of input values to the device maximum resolution
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values defined in the datasheet as such:
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@ -355,6 +355,7 @@ config SENSORS_DS1621
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Integrated DS1621 sensor chips and compatible models including:
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- Dallas Semiconductor DS1625
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- Maxim Integrated DS1631
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- Maxim Integrated DS1721
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This driver can also be built as a module. If so, the module
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@ -10,8 +10,8 @@
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* resolution, a thermal alarm output (Tout), and user-defined minimum
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* and maximum temperature thresholds (TH and TL).
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*
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* The DS1625 and DS1721 are pin compatible with the DS1621 and similar
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* in operation, with slight variations as noted in the device
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* The DS1625, DS1631, and DS1721 are pin compatible with the DS1621 and
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* similar in operation, with slight variations as noted in the device
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* datasheets (please refer to www.maximintegrated.com for specific
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* device information).
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*
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@ -51,7 +51,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
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0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
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/* Supported devices */
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enum chips { ds1621, ds1625, ds1721 };
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enum chips { ds1621, ds1625, ds1631, ds1721 };
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/* Insmod parameters */
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static int polarity = -1;
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@ -69,6 +69,10 @@ MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low")
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* 7 6 5 4 3 2 1 0
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* |Done|THF |TLF |NVB | 1 | 0 |POL |1SHOT|
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*
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* - DS1631:
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* 7 6 5 4 3 2 1 0
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* |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
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*
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* - DS1721:
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* 7 6 5 4 3 2 1 0
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* |Done| X | X | U | R1 | R0 |POL |1SHOT|
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@ -139,8 +143,8 @@ static inline int DS1621_TEMP_FROM_REG(u16 reg)
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/*
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* TEMP: 0.001C/bit (-55C to +125C)
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* REG:
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* - 1621, 1625: x = 0.5C
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* - 1721: x = 0.0625C
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* - 1621, 1625: 0.5C/bit
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* - 1631, 1721: 0.0625C/bit
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* Assume highest resolution and let the bits fall where they may..
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*/
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static inline u16 DS1621_TEMP_TO_REG(long temp)
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@ -174,6 +178,7 @@ static void ds1621_init_client(struct i2c_client *client)
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data->update_interval = DS1625_CONVERSION_MAX;
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sreg = DS1621_COM_START;
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break;
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case ds1631:
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case ds1721:
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resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
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DS1621_REG_CONFIG_RESOL_SHIFT;
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@ -342,7 +347,7 @@ static umode_t ds1621_attribute_visible(struct kobject *kobj,
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struct ds1621_data *data = i2c_get_clientdata(client);
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if (attr == &dev_attr_update_interval.attr)
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if (data->kind != ds1721)
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if (data->kind == ds1621 || data->kind == ds1625)
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/* shhh, we're hiding update_interval */
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return 0;
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return attr->mode;
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@ -376,7 +381,14 @@ static int ds1621_detect(struct i2c_client *client,
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conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
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if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
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return -ENODEV;
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/* The 7 lowest bits of a temperature should always be 0. */
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/*
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* The ds1621 & ds1625 use 9-bit resolution, so the 7 lowest bits
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* of the temperature should always be 0 (NOTE: The other chips
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* have multi-resolution support, so if they have 9-bit resolution
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* configured and the min/max temperature values set accordingly,
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* then if not explicitly instantiated, they *will* appear as and
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* emulate a ds1621 device).
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*/
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for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
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temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
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if (temp < 0 || (temp & 0x7f00))
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@ -438,6 +450,7 @@ static int ds1621_remove(struct i2c_client *client)
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static const struct i2c_device_id ds1621_id[] = {
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{ "ds1621", ds1621 },
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{ "ds1625", ds1625 },
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{ "ds1631", ds1631 },
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{ "ds1721", ds1721 },
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{ }
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};
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