diff options
| -rw-r--r-- | drivers/hwmon/pmbus/pmbus.h | 2 | ||||
| -rw-r--r-- | drivers/hwmon/pmbus/pmbus_core.c | 142 |
2 files changed, 139 insertions, 5 deletions
diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h index c031a9700ace..c708b60c1b48 100644 --- a/drivers/hwmon/pmbus/pmbus.h +++ b/drivers/hwmon/pmbus/pmbus.h @@ -406,7 +406,7 @@ enum pmbus_sensor_classes { #define PMBUS_PHASE_VIRTUAL BIT(30) /* Phases on this page are virtual */ #define PMBUS_PAGE_VIRTUAL BIT(31) /* Page is virtual */ -enum pmbus_data_format { linear = 0, direct, vid }; +enum pmbus_data_format { linear = 0, ieee754, direct, vid }; enum vrm_version { vr11 = 0, vr12, vr13, imvp9, amd625mv }; struct pmbus_driver_info { diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index e670b868e74b..bb21f1e79289 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -612,6 +612,66 @@ static void pmbus_update_sensor_data(struct i2c_client *client, struct pmbus_sen } /* + * Convert ieee754 sensor values to milli- or micro-units + * depending on sensor type. + * + * ieee754 data format: + * bit 15: sign + * bit 10..14: exponent + * bit 0..9: mantissa + * exponent=0: + * v=(−1)^signbit * 2^(−14) * 0.significantbits + * exponent=1..30: + * v=(−1)^signbit * 2^(exponent - 15) * 1.significantbits + * exponent=31: + * v=NaN + * + * Add the number mantissa bits into the calculations for simplicity. + * To do that, add '10' to the exponent. By doing that, we can just add + * 0x400 to normal values and get the expected result. + */ +static long pmbus_reg2data_ieee754(struct pmbus_data *data, + struct pmbus_sensor *sensor) +{ + int exponent; + bool sign; + long val; + + /* only support half precision for now */ + sign = sensor->data & 0x8000; + exponent = (sensor->data >> 10) & 0x1f; + val = sensor->data & 0x3ff; + + if (exponent == 0) { /* subnormal */ + exponent = -(14 + 10); + } else if (exponent == 0x1f) { /* NaN, convert to min/max */ + exponent = 0; + val = 65504; + } else { + exponent -= (15 + 10); /* normal */ + val |= 0x400; + } + + /* scale result to milli-units for all sensors except fans */ + if (sensor->class != PSC_FAN) + val = val * 1000L; + + /* scale result to micro-units for power sensors */ + if (sensor->class == PSC_POWER) + val = val * 1000L; + + if (exponent >= 0) + val <<= exponent; + else + val >>= -exponent; + + if (sign) + val = -val; + + return val; +} + +/* * Convert linear sensor values to milli- or micro-units * depending on sensor type. */ @@ -741,6 +801,9 @@ static s64 pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor) case vid: val = pmbus_reg2data_vid(data, sensor); break; + case ieee754: + val = pmbus_reg2data_ieee754(data, sensor); + break; case linear: default: val = pmbus_reg2data_linear(data, sensor); @@ -749,8 +812,72 @@ static s64 pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor) return val; } -#define MAX_MANTISSA (1023 * 1000) -#define MIN_MANTISSA (511 * 1000) +#define MAX_IEEE_MANTISSA (0x7ff * 1000) +#define MIN_IEEE_MANTISSA (0x400 * 1000) + +static u16 pmbus_data2reg_ieee754(struct pmbus_data *data, + struct pmbus_sensor *sensor, long val) +{ + u16 exponent = (15 + 10); + long mantissa; + u16 sign = 0; + + /* simple case */ + if (val == 0) + return 0; + + if (val < 0) { + sign = 0x8000; + val = -val; + } + + /* Power is in uW. Convert to mW before converting. */ + if (sensor->class == PSC_POWER) + val = DIV_ROUND_CLOSEST(val, 1000L); + + /* + * For simplicity, convert fan data to milli-units + * before calculating the exponent. + */ + if (sensor->class == PSC_FAN) + val = val * 1000; + + /* Reduce large mantissa until it fits into 10 bit */ + while (val > MAX_IEEE_MANTISSA && exponent < 30) { + exponent++; + val >>= 1; + } + /* + * Increase small mantissa to generate valid 'normal' + * number + */ + while (val < MIN_IEEE_MANTISSA && exponent > 1) { + exponent--; + val <<= 1; + } + + /* Convert mantissa from milli-units to units */ + mantissa = DIV_ROUND_CLOSEST(val, 1000); + + /* + * Ensure that the resulting number is within range. + * Valid range is 0x400..0x7ff, where bit 10 reflects + * the implied high bit in normalized ieee754 numbers. + * Set the range to 0x400..0x7ff to reflect this. + * The upper bit is then removed by the mask against + * 0x3ff in the final assignment. + */ + if (mantissa > 0x7ff) + mantissa = 0x7ff; + else if (mantissa < 0x400) + mantissa = 0x400; + + /* Convert to sign, 5 bit exponent, 10 bit mantissa */ + return sign | (mantissa & 0x3ff) | ((exponent << 10) & 0x7c00); +} + +#define MAX_LIN_MANTISSA (1023 * 1000) +#define MIN_LIN_MANTISSA (511 * 1000) static u16 pmbus_data2reg_linear(struct pmbus_data *data, struct pmbus_sensor *sensor, s64 val) @@ -796,12 +923,12 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, val = val * 1000LL; /* Reduce large mantissa until it fits into 10 bit */ - while (val >= MAX_MANTISSA && exponent < 15) { + while (val >= MAX_LIN_MANTISSA && exponent < 15) { exponent++; val >>= 1; } /* Increase small mantissa to improve precision */ - while (val < MIN_MANTISSA && exponent > -15) { + while (val < MIN_LIN_MANTISSA && exponent > -15) { exponent--; val <<= 1; } @@ -875,6 +1002,9 @@ static u16 pmbus_data2reg(struct pmbus_data *data, case vid: regval = pmbus_data2reg_vid(data, sensor, val); break; + case ieee754: + regval = pmbus_data2reg_ieee754(data, sensor, val); + break; case linear: default: regval = pmbus_data2reg_linear(data, sensor, val); @@ -2369,6 +2499,10 @@ static int pmbus_identify_common(struct i2c_client *client, if (data->info->format[PSC_VOLTAGE_OUT] != direct) return -ENODEV; break; + case 3: /* ieee 754 half precision */ + if (data->info->format[PSC_VOLTAGE_OUT] != ieee754) + return -ENODEV; + break; default: return -ENODEV; } |