When the LM73 temperature sensor measures a temperature below 0 C, the current driver does not perform sign extension, so the result returned is 512 C too high. This patch fixes the problem, and does general cleanup of the code.
Signed-off-by: Larry Johnson lrj@acm.org --- drivers/hwmon/lm73.c | 60 +++++++++++++++++++++++++------------------------- 1 files changed, 30 insertions(+), 30 deletions(-)
diff --git a/drivers/hwmon/lm73.c b/drivers/hwmon/lm73.c index db8ef66..98e8bd2 100644 --- a/drivers/hwmon/lm73.c +++ b/drivers/hwmon/lm73.c @@ -1,5 +1,5 @@ /* - * (C) Copyright 2007 + * (C) Copyright 2007-2008 * Larry Johnson, lrj@acm.org * * based on dtt/lm75.c which is ... @@ -39,10 +39,10 @@ */ #define DTT_I2C_DEV_CODE 0x48 /* National Semi's LM73 device */
-int dtt_read(int sensor, int reg) +int dtt_read(int const sensor, int const reg) { int dlen; - uchar data[2]; + uint8_t data[2];
/* * Validate 'reg' param and get register size. @@ -62,27 +62,24 @@ int dtt_read(int sensor, int reg) return -1; } /* - * Calculate sensor address and register. + * Try to read the register at the calculated sensor address. */ - sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate LM73 addr */ - /* - * Now try to read the register. - */ - if (i2c_read(sensor, reg, 1, data, dlen) != 0) + if (0 != + i2c_read(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, dlen)) return -1; /* * Handle 2 byte result. */ if (2 == dlen) - return ((int)((short)data[1] + (((short)data[0]) << 8))); + return (int)((unsigned)data[0] << 8 | (unsigned)data[1]);
return (int)data[0]; } /* dtt_read() */
-int dtt_write(int sensor, int reg, int val) +int dtt_write(int const sensor, int const reg, int const val) { int dlen; - uchar data[2]; + uint8_t data[2];
/* * Validate 'reg' param and handle register size @@ -91,28 +88,25 @@ int dtt_write(int sensor, int reg, int val) case DTT_CONFIG: case DTT_CONTROL: dlen = 1; - data[0] = (char)(val & 0xff); + data[0] = (uint8_t) val; break; case DTT_TEMP_HIGH: case DTT_TEMP_LOW: dlen = 2; - data[0] = (char)((val >> 8) & 0xff); /* MSB first */ - data[1] = (char)(val & 0xff); + data[0] = (uint8_t) (val >> 8); /* MSB first */ + data[1] = (uint8_t) val; break; default: return -1; } /* - * Calculate sensor address and register. - */ - sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate LM73 addr */ - /* - * Write value to register. + * Write value to register at the calculated sensor address. */ - return i2c_write(sensor, reg, 1, data, dlen) != 0; + return 0 != i2c_write(DTT_I2C_DEV_CODE + (sensor & 0x07), reg, 1, data, + dlen); } /* dtt_write() */
-static int _dtt_init(int sensor) +static int _dtt_init(int const sensor) { int val;
@@ -120,31 +114,31 @@ static int _dtt_init(int sensor) * Validate the Identification register */ if (0x0190 != dtt_read(sensor, DTT_ID)) - return 1; + return -1; /* * Setup THIGH (upper-limit) and TLOW (lower-limit) registers */ val = CFG_DTT_MAX_TEMP << 7; if (dtt_write(sensor, DTT_TEMP_HIGH, val)) - return 1; + return -1;
val = CFG_DTT_MIN_TEMP << 7; if (dtt_write(sensor, DTT_TEMP_LOW, val)) - return 1; + return -1; /* * Setup configuraton register */ /* config = alert active low, disabled, and reset */ val = 0x64; if (dtt_write(sensor, DTT_CONFIG, val)) - return 1; + return -1; /* * Setup control/status register */ /* control = temp resolution 0.25C */ val = 0x00; if (dtt_write(sensor, DTT_CONTROL, val)) - return 1; + return -1;
dtt_read(sensor, DTT_CONTROL); /* clear temperature flags */ return 0; @@ -157,7 +151,7 @@ int dtt_init(void) const char *const header = "DTT: ";
for (i = 0; i < sizeof(sensors); i++) { - if (_dtt_init(sensors[i]) != 0) + if (0 != _dtt_init(sensors[i])) printf("%s%d FAILED INIT\n", header, i + 1); else printf("%s%d is %i C\n", header, i + 1, @@ -166,7 +160,13 @@ int dtt_init(void) return 0; } /* dtt_init() */
-int dtt_get_temp(int sensor) +int dtt_get_temp(int const sensor) { - return (dtt_read(sensor, DTT_READ_TEMP) + 0x0040) >> 7; + int const ret = dtt_read(sensor, DTT_READ_TEMP); + + if (ret < 0) { + printf("DTT temperature read failed.\n"); + return 0; + } + return (int)((int16_t) ret + 0x0040) >> 7; } /* dtt_get_temp() */