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hwmon: (pmbus/ir35221) Remove unnecessary scaling
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The ir35221 datasheet describes specific scaling factors for a number of
commands which the current driver applies when reading.
However now that the ir35221 has been tested on machines with more
easily verifiable readings these descriptions have turned out to be
superfluous and reading each command according to the linear format is
sufficient.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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@sammj @groeck
sammj authored and groeck committed Jan 15, 2018
1 parent abe6c3b commit 08f411b
Showing 1 changed file with 0 additions and 189 deletions.
189 changes: 0 additions & 189 deletions drivers/hwmon/pmbus/ir35221.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,178 +25,26 @@
#define IR35221_MFR_IOUT_VALLEY 0xcb
#define IR35221_MFR_TEMP_VALLEY 0xcc

static long ir35221_reg2data(int data, enum pmbus_sensor_classes class)
{
s16 exponent;
s32 mantissa;
long val;

/* We only modify LINEAR11 formats */
exponent = ((s16)data) >> 11;
mantissa = ((s16)((data & 0x7ff) << 5)) >> 5;

val = mantissa * 1000L;

/* scale result to micro-units for power sensors */
if (class == PSC_POWER)
val = val * 1000L;

if (exponent >= 0)
val <<= exponent;
else
val >>= -exponent;

return val;
}

#define MAX_MANTISSA (1023 * 1000)
#define MIN_MANTISSA (511 * 1000)

static u16 ir35221_data2reg(long val, enum pmbus_sensor_classes class)
{
s16 exponent = 0, mantissa;
bool negative = false;

if (val == 0)
return 0;

if (val < 0) {
negative = true;
val = -val;
}

/* Power is in uW. Convert to mW before converting. */
if (class == PSC_POWER)
val = DIV_ROUND_CLOSEST(val, 1000L);

/* Reduce large mantissa until it fits into 10 bit */
while (val >= MAX_MANTISSA && exponent < 15) {
exponent++;
val >>= 1;
}
/* Increase small mantissa to improve precision */
while (val < MIN_MANTISSA && exponent > -15) {
exponent--;
val <<= 1;
}

/* Convert mantissa from milli-units to units */
mantissa = DIV_ROUND_CLOSEST(val, 1000);

/* Ensure that resulting number is within range */
if (mantissa > 0x3ff)
mantissa = 0x3ff;

/* restore sign */
if (negative)
mantissa = -mantissa;

/* Convert to 5 bit exponent, 11 bit mantissa */
return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
}

static u16 ir35221_scale_result(s16 data, int shift,
enum pmbus_sensor_classes class)
{
long val;

val = ir35221_reg2data(data, class);

if (shift < 0)
val >>= -shift;
else
val <<= shift;

return ir35221_data2reg(val, class);
}

static int ir35221_read_word_data(struct i2c_client *client, int page, int reg)
{
int ret;

switch (reg) {
case PMBUS_IOUT_OC_FAULT_LIMIT:
case PMBUS_IOUT_OC_WARN_LIMIT:
ret = pmbus_read_word_data(client, page, reg);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, 1, PSC_CURRENT_OUT);
break;
case PMBUS_VIN_OV_FAULT_LIMIT:
case PMBUS_VIN_OV_WARN_LIMIT:
case PMBUS_VIN_UV_WARN_LIMIT:
ret = pmbus_read_word_data(client, page, reg);
ret = ir35221_scale_result(ret, -4, PSC_VOLTAGE_IN);
break;
case PMBUS_IIN_OC_WARN_LIMIT:
ret = pmbus_read_word_data(client, page, reg);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, -1, PSC_CURRENT_IN);
break;
case PMBUS_READ_VIN:
ret = pmbus_read_word_data(client, page, PMBUS_READ_VIN);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, -5, PSC_VOLTAGE_IN);
break;
case PMBUS_READ_IIN:
ret = pmbus_read_word_data(client, page, PMBUS_READ_IIN);
if (ret < 0)
break;
if (page == 0)
ret = ir35221_scale_result(ret, -4, PSC_CURRENT_IN);
else
ret = ir35221_scale_result(ret, -5, PSC_CURRENT_IN);
break;
case PMBUS_READ_POUT:
ret = pmbus_read_word_data(client, page, PMBUS_READ_POUT);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, -1, PSC_POWER);
break;
case PMBUS_READ_PIN:
ret = pmbus_read_word_data(client, page, PMBUS_READ_PIN);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, -1, PSC_POWER);
break;
case PMBUS_READ_IOUT:
ret = pmbus_read_word_data(client, page, PMBUS_READ_IOUT);
if (ret < 0)
break;
if (page == 0)
ret = ir35221_scale_result(ret, -1, PSC_CURRENT_OUT);
else
ret = ir35221_scale_result(ret, -2, PSC_CURRENT_OUT);
break;
case PMBUS_VIRT_READ_VIN_MAX:
ret = pmbus_read_word_data(client, page, IR35221_MFR_VIN_PEAK);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, -5, PSC_VOLTAGE_IN);
break;
case PMBUS_VIRT_READ_VOUT_MAX:
ret = pmbus_read_word_data(client, page, IR35221_MFR_VOUT_PEAK);
break;
case PMBUS_VIRT_READ_IOUT_MAX:
ret = pmbus_read_word_data(client, page, IR35221_MFR_IOUT_PEAK);
if (ret < 0)
break;
if (page == 0)
ret = ir35221_scale_result(ret, -1, PSC_CURRENT_IN);
else
ret = ir35221_scale_result(ret, -2, PSC_CURRENT_IN);
break;
case PMBUS_VIRT_READ_TEMP_MAX:
ret = pmbus_read_word_data(client, page, IR35221_MFR_TEMP_PEAK);
break;
case PMBUS_VIRT_READ_VIN_MIN:
ret = pmbus_read_word_data(client, page,
IR35221_MFR_VIN_VALLEY);
if (ret < 0)
break;
ret = ir35221_scale_result(ret, -5, PSC_VOLTAGE_IN);
break;
case PMBUS_VIRT_READ_VOUT_MIN:
ret = pmbus_read_word_data(client, page,
Expand All @@ -205,12 +53,6 @@ static int ir35221_read_word_data(struct i2c_client *client, int page, int reg)
case PMBUS_VIRT_READ_IOUT_MIN:
ret = pmbus_read_word_data(client, page,
IR35221_MFR_IOUT_VALLEY);
if (ret < 0)
break;
if (page == 0)
ret = ir35221_scale_result(ret, -1, PSC_CURRENT_IN);
else
ret = ir35221_scale_result(ret, -2, PSC_CURRENT_IN);
break;
case PMBUS_VIRT_READ_TEMP_MIN:
ret = pmbus_read_word_data(client, page,
Expand All @@ -224,36 +66,6 @@ static int ir35221_read_word_data(struct i2c_client *client, int page, int reg)
return ret;
}

static int ir35221_write_word_data(struct i2c_client *client, int page, int reg,
u16 word)
{
int ret;
u16 val;

switch (reg) {
case PMBUS_IOUT_OC_FAULT_LIMIT:
case PMBUS_IOUT_OC_WARN_LIMIT:
val = ir35221_scale_result(word, -1, PSC_CURRENT_OUT);
ret = pmbus_write_word_data(client, page, reg, val);
break;
case PMBUS_VIN_OV_FAULT_LIMIT:
case PMBUS_VIN_OV_WARN_LIMIT:
case PMBUS_VIN_UV_WARN_LIMIT:
val = ir35221_scale_result(word, 4, PSC_VOLTAGE_IN);
ret = pmbus_write_word_data(client, page, reg, val);
break;
case PMBUS_IIN_OC_WARN_LIMIT:
val = ir35221_scale_result(word, 1, PSC_CURRENT_IN);
ret = pmbus_write_word_data(client, page, reg, val);
break;
default:
ret = -ENODATA;
break;
}

return ret;
}

static int ir35221_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
Expand Down Expand Up @@ -292,7 +104,6 @@ static int ir35221_probe(struct i2c_client *client,
if (!info)
return -ENOMEM;

info->write_word_data = ir35221_write_word_data;
info->read_word_data = ir35221_read_word_data;

info->pages = 2;
Expand Down

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