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Commit daa436e6 authored by Guenter Roeck's avatar Guenter Roeck
Browse files

hwmon: (pmbus) Support per-page exponent in linear mode 



Some chips use different exponents for sensors on different pages
or rails. Detect and store exponent per page to support this situation.

This fixes a problem with wrong voltages seen on UCD90120.

Reported-by: default avatarSoren Brinkmann <soren.brinkmann@xilinx.com>
Tested-by: default avatarSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 38dbfb59

drivers/hwmon/pmbus/pmbus_core.c

+36 −32
Original line number Diff line number Diff line
@@ -90,7 +90,8 @@ struct pmbus_data { 


	u32 flags;		/* from platform data */



	int exponent;		/* linear mode: exponent for output voltages */

	int exponent[PMBUS_PAGES];

				/* linear mode: exponent for output voltages */



	const struct pmbus_driver_info *info;
@@ -410,7 +411,7 @@ static long pmbus_reg2data_linear(struct pmbus_data *data, 
	long val;



	if (sensor->class == PSC_VOLTAGE_OUT) {	/* LINEAR16 */

		exponent = data->exponent;

		exponent = data->exponent[sensor->page];

		mantissa = (u16) sensor->data;

	} else {				/* LINEAR11 */

		exponent = ((s16)sensor->data) >> 11;
@@ -516,7 +517,7 @@ static long pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor) 
#define MIN_MANTISSA	(511 * 1000)



static u16 pmbus_data2reg_linear(struct pmbus_data *data,

				 enum pmbus_sensor_classes class, long val)

				 struct pmbus_sensor *sensor, long val)

{

	s16 exponent = 0, mantissa;

	bool negative = false;
@@ -525,7 +526,7 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, 
	if (val == 0)

		return 0;



	if (class == PSC_VOLTAGE_OUT) {

	if (sensor->class == PSC_VOLTAGE_OUT) {

		/* LINEAR16 does not support negative voltages */

		if (val < 0)

			return 0;
@@ -534,10 +535,10 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, 
		 * For a static exponents, we don't have a choice

		 * but to adjust the value to it.

		 */

		if (data->exponent < 0)

			val <<= -data->exponent;

		if (data->exponent[sensor->page] < 0)

			val <<= -data->exponent[sensor->page];

		else

			val >>= data->exponent;

			val >>= data->exponent[sensor->page];

		val = DIV_ROUND_CLOSEST(val, 1000);

		return val & 0xffff;

	}
@@ -548,14 +549,14 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, 
	}



	/* Power is in uW. Convert to mW before converting. */

	if (class == PSC_POWER)

	if (sensor->class == PSC_POWER)

		val = DIV_ROUND_CLOSEST(val, 1000L);



	/*

	 * For simplicity, convert fan data to milli-units

	 * before calculating the exponent.

	 */

	if (class == PSC_FAN)

	if (sensor->class == PSC_FAN)

		val = val * 1000;



	/* Reduce large mantissa until it fits into 10 bit */
@@ -585,22 +586,22 @@ static u16 pmbus_data2reg_linear(struct pmbus_data *data, 
}



static u16 pmbus_data2reg_direct(struct pmbus_data *data,

				 enum pmbus_sensor_classes class, long val)

				 struct pmbus_sensor *sensor, long val)

{

	long m, b, R;



	m = data->info->m[class];

	b = data->info->b[class];

	R = data->info->R[class];

	m = data->info->m[sensor->class];

	b = data->info->b[sensor->class];

	R = data->info->R[sensor->class];



	/* Power is in uW. Adjust R and b. */

	if (class == PSC_POWER) {

	if (sensor->class == PSC_POWER) {

		R -= 3;

		b *= 1000;

	}



	/* Calculate Y = (m * X + b) * 10^R */

	if (class != PSC_FAN) {

	if (sensor->class != PSC_FAN) {

		R -= 3;		/* Adjust R and b for data in milli-units */

		b *= 1000;

	}
@@ -619,7 +620,7 @@ static u16 pmbus_data2reg_direct(struct pmbus_data *data, 
}



static u16 pmbus_data2reg_vid(struct pmbus_data *data,

			      enum pmbus_sensor_classes class, long val)

			      struct pmbus_sensor *sensor, long val)

{

	val = clamp_val(val, 500, 1600);
@@ -627,20 +628,20 @@ static u16 pmbus_data2reg_vid(struct pmbus_data *data, 
}



static u16 pmbus_data2reg(struct pmbus_data *data,

			  enum pmbus_sensor_classes class, long val)

			  struct pmbus_sensor *sensor, long val)

{

	u16 regval;



	switch (data->info->format[class]) {

	switch (data->info->format[sensor->class]) {

	case direct:

		regval = pmbus_data2reg_direct(data, class, val);

		regval = pmbus_data2reg_direct(data, sensor, val);

		break;

	case vid:

		regval = pmbus_data2reg_vid(data, class, val);

		regval = pmbus_data2reg_vid(data, sensor, val);

		break;

	case linear:

	default:

		regval = pmbus_data2reg_linear(data, class, val);

		regval = pmbus_data2reg_linear(data, sensor, val);

		break;

	}

	return regval;
@@ -746,7 +747,7 @@ static ssize_t pmbus_set_sensor(struct device *dev, 
		return -EINVAL;



	mutex_lock(&data->update_lock);

	regval = pmbus_data2reg(data, sensor->class, val);

	regval = pmbus_data2reg(data, sensor, val);

	ret = _pmbus_write_word_data(client, sensor->page, sensor->reg, regval);

	if (ret < 0)

		rv = ret;
@@ -1643,12 +1644,13 @@ static int pmbus_find_attributes(struct i2c_client *client, 
 * This function is called for all chips.

 */

static int pmbus_identify_common(struct i2c_client *client,

				 struct pmbus_data *data)

				 struct pmbus_data *data, int page)

{

	int vout_mode = -1;



	if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE))

		vout_mode = _pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);

	if (pmbus_check_byte_register(client, page, PMBUS_VOUT_MODE))

		vout_mode = _pmbus_read_byte_data(client, page,

						  PMBUS_VOUT_MODE);

	if (vout_mode >= 0 && vout_mode != 0xff) {

		/*

		 * Not all chips support the VOUT_MODE command,
@@ -1659,7 +1661,7 @@ static int pmbus_identify_common(struct i2c_client *client, 
			if (data->info->format[PSC_VOLTAGE_OUT] != linear)

				return -ENODEV;



			data->exponent = ((s8)(vout_mode << 3)) >> 3;

			data->exponent[page] = ((s8)(vout_mode << 3)) >> 3;

			break;

		case 1: /* VID mode         */

			if (data->info->format[PSC_VOLTAGE_OUT] != vid)
@@ -1674,7 +1676,7 @@ static int pmbus_identify_common(struct i2c_client *client, 
		}

	}



	pmbus_clear_fault_page(client, 0);

	pmbus_clear_fault_page(client, page);

	return 0;

}
@@ -1682,7 +1684,7 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data, 
			     struct pmbus_driver_info *info)

{

	struct device *dev = &client->dev;

	int ret;

	int page, ret;



	/*

	 * Some PMBus chips don't support PMBUS_STATUS_BYTE, so try
@@ -1715,11 +1717,13 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data, 
		return -ENODEV;

	}



	ret = pmbus_identify_common(client, data);

	for (page = 0; page < info->pages; page++) {

		ret = pmbus_identify_common(client, data, page);

		if (ret < 0) {

			dev_err(dev, "Failed to identify chip capabilities\n");

			return ret;

		}

	}

	return 0;

}