linux-toradex.git/drivers/hwmon/pmbus, branch master

hwmon: (pmbus/tps53679) Select page 0 for single-page TPS53676

2026-09-17T00:05:22+00:00

tps53676_identify() derives the number of PMBus pages but does not
ensure that page 0 is selected for single-page configurations.
pmbus_set_page() does not update the PAGE register when info->pages is
1, so if boot firmware leaves PAGE set to another value subsequent
register accesses may target the wrong page.

For single-page devices, select page 0 explicitly.

Fixes: cb3d37b59012 ("hwmon: (pmbus/tps53679) Add support for TI TPS53676")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan 
Link: https://patch.msgid.link/20260916235406.681131-2-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck

hwmon: (pmbus/tps53679) Fix TPS53676 phase page decoding

2026-09-16T14:56:04+00:00

tps53676_identify() reads the USER_DATA_03 phase configuration to count
the phases assigned to each channel and derive the number of PMBus pages.
In each 16-bit phase descriptor the channel (PAGE) is encoded in bit 4 and
the firing order in bits 3:0, but the code tested bit 3 (0x08), which is
part of the firing-order field.

TPS53676 supports up to seven phases, so firing-order bit 3 is never set.
As a result the existing test classifies every enabled phase as channel A.
On a dual-channel configuration the phases assigned to channel B are
therefore miscounted as channel A and page 1 is not exposed.

Test the PAGE field (bit 4) instead.

Fixes: cb3d37b59012 ("hwmon: (pmbus/tps53679) Add support for TI TPS53676")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan 
Link: https://patch.msgid.link/20260915164823.160977-2-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck

hwmon: (pmbus/core) increase number of phases and add new mask

2026-09-14T04:19:48+00:00

Increase the number of phases to 16 as a new upcoming device supports
such a number.

While at it, add a new mask for controlling the source of the output
voltage.

Note (groeck):

This patch was meant to prepare for support of MAX20826 and compatible
devices, which support more than 10 phases per page. However, Sashiko
reports that the mp2975 driver already supports up to 14 phases, and the
mp2856 driver supports up to 12 phases. This already has the potential for
out-of-bounds writes when probing the affected chips, making this patch a
bug fix.

Fixes: 2c6fcbb21149 ("hwmon: (pmbus) Add support for MPS Multi-phase mp2975 controller")
Fixes: f9e5f289b686 ("hwmon: (pmbus) Add support for MPS Multi-phase mp2856/mp2857 controller")
Signed-off-by: Nuno Sá 
Link: https://patch.msgid.link/20260911-hwmon-max20826-support-v2-1-5e30cbd97d84@analog.com
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck

hwmon: (pmbus) Clear generic status alarms with CLEAR_FAULTS

2026-09-10T01:16:34+00:00

Some hwmon alarms fall back to STATUS_WORD summary bits when no
individual limit alarm is available. On PMBus 1.2 and newer devices,
pmbus_get_boolean() acknowledges these alarms with the same byte-data
write used for detailed status registers. For example, PB_STATUS_INPUT
is 0x2000, so it is truncated to zero when passed to
_pmbus_write_byte_data(). The resulting write cannot acknowledge the
input alarm.

PMBus 1.3 Part II, sections 10.2.4 and 10.2.5, excludes ordinary
STATUS_BYTE and STATUS_WORD summary bits from individual clearing.
Their summary bits clear when the underlying status bits clear, so
changing this to a word-data write would not fix the generic input
alarm either.

Use the existing page CLEAR_FAULTS path for generic STATUS_WORD
alarms, including devices whose status accessor uses STATUS_BYTE.
Keep individual byte writes for detailed status registers on PMBus
1.2 and newer devices. As with the existing older-device fallback,
CLEAR_FAULTS can clear other latched status; an active condition can
reassert its status.

Fixes: 35f165f08950 ("hwmon: (pmbus) Clear pmbus fault/warning bits after read")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Vishnu Razdan 
Link: https://patch.msgid.link/20260824-vrazdan-pmbus-status-word-b4-v1-1-2606ecd0c029@openai.com
Signed-off-by: Guenter Roeck

hwmon: (pmbus/ir36021) Use pmbus_read_smbus_i2c_block_data for block commands

2026-08-10T15:59:43+00:00

The driver uses i2c_smbus_read_i2c_block_data() for PMBus block commands.
Use pmbus_read_smbus_i2c_block_data() instead to enable the driver to work
with I2C controllers which do not support i2c_smbus_read_i2c_block_data().

Drop the functionality check to get an explicit error message if the
required SMBus commands are not supported.

Reviewed-by: Nuno Sá 
Signed-off-by: Guenter Roeck

hwmon: (pmbus/max20830) Use pmbus_read_smbus_i2c_block_data for block commands

2026-08-10T15:59:43+00:00

The driver tries to use both pmbus_read_smbus_i2c_block_data() and
i2c_smbus_read_i2c_block_data() for PMBus block commands.

Use pmbus_read_smbus_i2c_block_data() instead to simplify the code.

Drop the functionality check to simplify the code and to trigger a return
with -EOPNOTSUPP if SMBus block commands are not supported.

Cc: Alexis Czezar Torreno 
Cc: Nuno Sá 
Reviewed-by: Nuno Sá 
Signed-off-by: Guenter Roeck

hwmon: (pmbus/ltc2978) Use pmbus_read_smbus_i2c_block_data for block commands

2026-08-10T15:59:43+00:00

The driver uses a mix of pmbus_read_smbus_i2c_block_data() and
i2c_smbus_read_i2c_block_data() for PMBus block commands.

Use pmbus_read_smbus_i2c_block_data() instead to enable the driver to work
I2C controllers which do not support both block commands.

Drop the functionality check to simplify the code and to trigger a return
with -EOPNOTSUPP if SMBus block commands are not supported.

As part of this patch, rework detection of LT7170 and LT7171. The return
length of pmbus_read_smbus_i2c_block_data() may be less than the requested
number of bytes, meaning the return length needs to be checked. Also,
checking for "LT7170-1" after checking for "LT7170" and checking for
"LT7171-1" after checking for "LT7171" is pointless since the first check
will already produce a match, so drop the second part of the check.

Cc: Alexis Czezar Torreno 
Cc: Nuno Sá 
Reviewed-by: Nuno Sá 
Signed-off-by: Guenter Roeck

hwmon: (pmbus/adm1275) Use pmbus_read_smbus_i2c_block_data for block commands

2026-08-10T15:59:43+00:00

The driver uses i2c_smbus_read_block_data() for PMBus block commands.
Use pmbus_read_smbus_i2c_block_data() instead to enable the driver to work
with I2C controllers which do not support i2c_smbus_read_block_data().

Drop the functionality check to get an explicit error message if the
required SMBus commands are not supported.

Reviewed-by: Nuno Sá 
Signed-off-by: Guenter Roeck

hwmon: (pmbus/core) Introduce pmbus_read_smbus_i2c_block_data()

2026-08-10T15:59:43+00:00

PMBus drivers need support for reading SMBus block data. Unfortunately,
not all i2C controllers support this command.

Implement pmbus_read_smbus_i2c_block_data() which first tries to use
i2c_smbus_read_block_data(). If not supported, try to emulate it by calling
i2c_smbus_read_i2c_block_data(). Export the new function for use in PMBus
drivers.

Cc: Alexis Czezar Torreno 
Cc: Nuno Sá 
Reviewed-by: Nuno Sá 
Signed-off-by: Guenter Roeck

hwmon: (pmbus/mpq8646) Gate the writes

2026-08-10T15:59:43+00:00

The write cases of debugfs entries are provisioning and bench
helpers. By designs the MPQ8646 powers the CPU core rail,
so a wrong write can brown out the board or persist a bad
setpoint into finite-cycle NVM.
Said differently: some wrong register writes can and likely
will physically damage or destroy the chip and/or the board.

To be safe, it is disabled by default behind a
CONFIG_SENSORS_MPQ8646_DEBUG_UNSAFE and we print an explicit warning
banner at probe time when they are built in.

Signed-off-by: Vincent Jardin 
Link: https://lore.kernel.org/r/20260730-mpq8646_v0-v7-4-e7c7ad768d5d@free.fr
Signed-off-by: Guenter Roeck