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w1: w1_therm: Add support for GXCAS GX20MH01 device.
GX20MH01 device shares family number 0x28 with DS18B20. The device is generally compatible with DS18B20. Added are the lowest 2^-5, 2^-6 temperature bits in Config register; R2 bit in Config register enabling 13 and 14 bit resolutions. It is powered up in 14 bit mode. Signed-off-by: Ivan Zaentsev <ivan.zaentsev@wirenboard.ru> Link: https://lore.kernel.org/r/20200904160004.87710-2-ivan.zaentsev@wirenboard.ru Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ivan Zaentsev
Greg Kroah-Hartman
parent
021da53e65
commit
9ace0b4dab
@ -49,7 +49,7 @@ Description:
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will be changed only in device RAM, so it will be cleared when
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power is lost. Trigger a 'save' to EEPROM command to keep
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values after power-on. Read or write are :
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* '9..12': device resolution in bit
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* '9..14': device resolution in bit
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or resolution to set in bit
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* '-xx': xx is kernel error when reading the resolution
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* Anything else: do nothing
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@ -89,7 +89,7 @@ Description:
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*write* :
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* '0' : save the 2 or 3 bytes to the device EEPROM
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(i.e. TH, TL and config register)
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* '9..12' : set the device resolution in RAM
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* '9..14' : set the device resolution in RAM
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(if supported)
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* Anything else: do nothing
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refer to Documentation/w1/slaves/w1_therm.rst for detailed
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@ -6,6 +6,7 @@ Supported chips:
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* Maxim ds18*20 based temperature sensors.
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* Maxim ds1825 based temperature sensors.
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* GXCAS GC20MH01 temperature sensor.
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Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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@ -13,8 +14,8 @@ Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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Description
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-----------
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w1_therm provides basic temperature conversion for ds18*20 devices, and the
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ds28ea00 device.
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w1_therm provides basic temperature conversion for ds18*20, ds28ea00, GX20MH01
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devices.
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Supported family codes:
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@ -130,4 +131,12 @@ conversion and temperature reads 85.00 (powerup value) or 127.94 (insufficient
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power), the driver returns a conversion error. Bit mask ``2`` enables poll for
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conversion completion (normal power only) by generating read cycles on the bus
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after conversion starts. In parasite power mode this feature is not available.
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Feature bit masks may be combined (OR).
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Feature bit masks may be combined (OR). See accompanying sysfs documentation:
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:ref:`Documentation/w1/slaves/w1_therm.rst <w1_therm>`
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GX20MH01 device shares family number 0x28 with DS18*20. The device is generally
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compatible with DS18B20. Added are lowest 2^-5, 2^-6 temperature bits in Config
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register; R2 bit in Config register enabling 13 and 14 bit resolutions. The
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device is powered up in 14-bit resolution mode. The conversion times specified
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in the datasheet are too low and have to be increased. The device supports
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driver features ``1`` and ``2``.
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@ -80,6 +80,18 @@ static u16 bulk_read_device_counter; /* =0 as per C standard */
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#define W1_POLL_CONVERT_TEMP 2000 /* Timeout for W1_CONVERT_TEMP, ms */
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#define W1_POLL_RECALL_EEPROM 500 /* Timeout for W1_RECALL_EEPROM, ms*/
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/* Masks for resolution functions, work with all devices */
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/* Bit mask for config register for all devices, bits 7,6,5 */
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#define W1_THERM_RESOLUTION_MASK 0xE0
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/* Bit offset of resolution in config register for all devices */
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#define W1_THERM_RESOLUTION_SHIFT 5
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/* Bit offset of resolution in config register for all devices */
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#define W1_THERM_RESOLUTION_SHIFT 5
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/* Add this to bit value to get resolution */
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#define W1_THERM_RESOLUTION_MIN 9
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/* Maximum allowed value */
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#define W1_THERM_RESOLUTION_MAX 14
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/* Helpers Macros */
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/*
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@ -523,7 +535,9 @@ static inline int w1_DS18B20_convert_time(struct w1_slave *sl)
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if (SLAVE_CONV_TIME_OVERRIDE(sl) != CONV_TIME_DEFAULT)
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return SLAVE_CONV_TIME_OVERRIDE(sl);
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/* Return the conversion time from datasheet, depending on resolution */
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/* Return the conversion time, depending on resolution,
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* select maximum conversion time among all compatible devices
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*/
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switch (SLAVE_RESOLUTION(sl)) {
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case 9:
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ret = 95;
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@ -535,6 +549,14 @@ static inline int w1_DS18B20_convert_time(struct w1_slave *sl)
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ret = 375;
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break;
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case 12:
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ret = 750;
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break;
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case 13:
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ret = 850; /* GX20MH01 only. Datasheet says 500ms, but that's not enough. */
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break;
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case 14:
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ret = 1600; /* GX20MH01 only. Datasheet says 1000ms - not enough */
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break;
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default:
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ret = 750;
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}
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@ -568,62 +590,71 @@ static inline int w1_DS18S20_write_data(struct w1_slave *sl,
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static inline int w1_DS18B20_set_resolution(struct w1_slave *sl, int val)
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{
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int ret;
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u8 new_config_register[3]; /* array of data to be written */
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struct therm_info info, info2;
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/* resolution of DS18B20 is in the range [9..12] bits */
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if (val < 9 || val > 12)
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/* DS18B20 resolution is 9 to 12 bits */
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/* GX20MH01 resolution is 9 to 14 bits */
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if (val < W1_THERM_RESOLUTION_MIN || val > W1_THERM_RESOLUTION_MAX)
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return -EINVAL;
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val -= 9; /* soustract 9 the lowest resolution in bit */
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val = (val << 5); /* shift to position bit 5 & bit 6 */
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/* Calc bit value from resolution */
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val = (val - W1_THERM_RESOLUTION_MIN) << W1_THERM_RESOLUTION_SHIFT;
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/*
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* Read the scratchpad to change only the required bits
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* (bit5 & bit 6 from byte 4)
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*/
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ret = read_scratchpad(sl, &info);
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if (!ret) {
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new_config_register[0] = info.rom[2];
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new_config_register[1] = info.rom[3];
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/* config register is byte 4 & mask 0b10011111*/
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new_config_register[2] = (info.rom[4] & 0x9F) |
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(u8) val;
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} else
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if (ret)
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return ret;
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info.rom[4] &= ~W1_THERM_RESOLUTION_MASK;
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info.rom[4] |= val;
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/* Write data in the device RAM */
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ret = w1_DS18B20_write_data(sl, new_config_register);
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ret = w1_DS18B20_write_data(sl, info.rom + 2);
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if (ret)
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return ret;
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/* Some DS18B20 clones don't support resolution change, read back to verify */
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/* Have to read back the resolution to verify an actual value
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* GX20MH01 and DS18B20 are indistinguishable by family number, but resolutions differ
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* Some DS18B20 clones don't support resolution change
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*/
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ret = read_scratchpad(sl, &info2);
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if (ret)
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/* Scratchpad read fail */
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return ret;
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if ((info2.rom[4] & 0x9F) == (info.rom[4] & 0x9F))
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if ((info2.rom[4] & W1_THERM_RESOLUTION_MASK) == (info.rom[4] & W1_THERM_RESOLUTION_MASK))
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return 0;
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else
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return -EIO;
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/* Resolution verify error */
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return -EIO;
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}
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static inline int w1_DS18B20_get_resolution(struct w1_slave *sl)
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{
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int ret;
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u8 config_register;
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int resolution;
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struct therm_info info;
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ret = read_scratchpad(sl, &info);
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if (!ret) {
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config_register = info.rom[4]; /* config register is byte 4 */
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config_register &= 0x60; /* 0b01100000 keep only bit 5 & 6 */
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config_register = (config_register >> 5); /* shift */
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config_register += 9; /* add 9 the lowest resolution in bit */
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ret = (int) config_register;
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}
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return ret;
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if (ret)
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return ret;
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resolution = ((info.rom[4] & W1_THERM_RESOLUTION_MASK) >> W1_THERM_RESOLUTION_SHIFT)
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+ W1_THERM_RESOLUTION_MIN;
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/* GX20MH01 has one special case:
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* >=14 means 14 bits when getting resolution from bit value.
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* Other devices have no more then 12 bits.
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*/
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if (resolution > W1_THERM_RESOLUTION_MAX)
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resolution = W1_THERM_RESOLUTION_MAX;
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return resolution;
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}
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/**
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@ -636,11 +667,28 @@ static inline int w1_DS18B20_get_resolution(struct w1_slave *sl)
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*/
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static inline int w1_DS18B20_convert_temp(u8 rom[9])
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{
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s16 t = le16_to_cpup((__le16 *)rom);
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int t;
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u32 bv;
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/* Config register bit R2 = 1 - GX20MH01 in 13 or 14 bit resolution mode */
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if (rom[4] & 0x80) {
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/* Signed 16-bit value to unsigned, cpu order */
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bv = le16_to_cpup((__le16 *)rom);
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/* Insert two temperature bits from config register */
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/* Avoid arithmetic shift of signed value */
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bv = (bv << 2) | (rom[4] & 3);
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t = (int) sign_extend32(bv, 17); /* Degrees, lowest bit is 2^-6 */
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return (t*1000)/64; /* Millidegrees */
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}
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t = (int)le16_to_cpup((__le16 *)rom);
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return t*1000/16;
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}
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/**
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* w1_DS18S20_convert_temp() - temperature computation for DS18S20
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* @rom: data read from device RAM (8 data bytes + 1 CRC byte)
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@ -672,6 +720,7 @@ static inline int w1_DS18S20_convert_temp(u8 rom[9])
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}
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/* Device capability description */
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/* GX20MH01 device shares family number and structure with DS18B20 */
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static struct w1_therm_family_converter w1_therm_families[] = {
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{
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@ -693,6 +742,7 @@ static struct w1_therm_family_converter w1_therm_families[] = {
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.bulk_read = true
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},
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{
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/* Also used for GX20MH01 */
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.f = &w1_therm_family_DS18B20,
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.convert = w1_DS18B20_convert_temp,
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.get_conversion_time = w1_DS18B20_convert_time,
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