Commit c2a338c9 authored by Václav Kubernát's avatar Václav Kubernát Committed by Guenter Roeck
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hwmon: (pmbus/fsp-3y) Fix FSP-3Y YH-5151E VOUT 



After testing new YH-5151E devices, we found out that not all YH-5151E
work the same. The newly tested devices actually report vout correctly
in linear16 (even though they're still YH-5151E). We suspect that it is
because these new devices have a different firmware version, but that is
unconfirmed. The version cannot be queried through PMBus.

The compliant versions of YH-5151E report VOUT_MODE normally, so we turn
on the linear11 workaround only if VOUT_MODE doesn't report anything.

Signed-off-by: default avatarVáclav Kubernát <kubernat@cesnet.cz>
Link: https://lore.kernel.org/r/20210513201110.313523-1-kubernat@cesnet.cz


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 35d470b5

drivers/hwmon/pmbus/fsp-3y.c

+25 −7
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ struct fsp3y_data { 
	struct pmbus_driver_info info;

	int chip;

	int page;



	bool vout_linear_11;

};



#define to_fsp3y_data(x) container_of(x, struct fsp3y_data, info)
@@ -108,11 +110,9 @@ static int fsp3y_read_byte_data(struct i2c_client *client, int page, int reg) 
	int rv;



	/*

	 * YH5151-E outputs vout in linear11. The conversion is done when

	 * reading. Here, we have to inject pmbus_core with the correct

	 * exponent (it is -6).

	 * Inject an exponent for non-compliant YH5151-E.

	 */

	if (data->chip == yh5151e && reg == PMBUS_VOUT_MODE)

	if (data->vout_linear_11 && reg == PMBUS_VOUT_MODE)

		return 0x1A;



	rv = set_page(client, page);
@@ -161,10 +161,9 @@ static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase, 
		return rv;



	/*

	 * YH-5151E is non-compliant and outputs output voltages in linear11

	 * instead of linear16.

	 * Handle YH-5151E non-compliant linear11 vout voltage.

	 */

	if (data->chip == yh5151e && reg == PMBUS_READ_VOUT)

	if (data->vout_linear_11 && reg == PMBUS_READ_VOUT)

		rv = sign_extend32(rv, 10) & 0xffff;



	return rv;
@@ -256,6 +255,25 @@ static int fsp3y_probe(struct i2c_client *client) 


	data->info = fsp3y_info[data->chip];



	/*

	 * YH-5151E sometimes reports vout in linear11 and sometimes in

	 * linear16. This depends on the exact individual piece of hardware. One

	 * YH-5151E can use linear16 and another might use linear11 instead.

	 *

	 * The format can be recognized by reading VOUT_MODE - if it doesn't

	 * report a valid exponent, then vout uses linear11. Otherwise, the

	 * device is compliant and uses linear16.

	 */

	data->vout_linear_11 = false;

	if (data->chip == yh5151e) {

		rv = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);

		if (rv < 0)

			return rv;



		if (rv == 0xFF)

			data->vout_linear_11 = true;

	}



	return pmbus_do_probe(client, &data->info);

}