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hwmon: (pmbus/tps53679) Select page 0 for single-page TPS536C7

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tps536c7_identify() sets info->pages to 1 for a single-channel part and
then accesses page 0 (writing PMBUS_PHASE) without ensuring PAGE is
actually 0. pmbus_set_page() does not update the PAGE register when
info->pages is 1, so if boot firmware left PAGE set to another value the
PHASE writes and subsequent telemetry may target the wrong page.

Select page 0 explicitly before configuring PHASE.

Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://patch.msgid.link/20260916235406.681131-3-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Sanman Pradhan 2026-09-16 23:54:21 +00:00 committed by Guenter Roeck
parent 4810ec90c4
commit c3147b4d1b
1 changed files with 11 additions and 0 deletions
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11
drivers/hwmon/pmbus/tps53679.c
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@ -283,6 +283,17 @@ static int tps536c7_identify(struct i2c_client *client,
*/
info->pages = phases_b ? 2 : 1;
/*
* pmbus_set_page() does not update the PAGE register on single-page
* devices, so select page 0 explicitly in case the boot firmware
* left the device on another page.
*/
if (info->pages == 1) {
ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
if (ret < 0)
return ret;
}
/*
* With info->phases[] left unset the PMBus core never programs the
* PHASE selector, so make sure each page reports the aggregate