diff options
| author | Carl Lee <carl.lee@amd.com> | 2026-02-10 15:26:34 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-26 15:01:04 -0800 |
| commit | 3e66bdc27aaf1f4d73defc55ecec7bc569401e2a (patch) | |
| tree | e3ff81fa4bcc38064edb7e17a230e1bd12484d81 /drivers/hwmon | |
| parent | 894d9c7aab68fd0c70c78b1d03c8fa589fb0f67d (diff) | |
hwmon: (pmbus/mpq8785) fix VOUT_MODE mismatch during identification
[ Upstream commit 9e33c1dba22431bea9b2bf48adf56859e52fc7ec ]
When MPQ8785 reports VOUT_MODE as VID mode, mpq8785_identify()
configures the driver for direct mode. The subsequent
pmbus_identify_common() check then fails due to a mismatch
between the reported mode and the configured mode, causing
device initialization to fail.
Override the reported VOUT_MODE to direct mode to keep the
driver configuration consistent with the reported mode and
allow successful device initialization.
This does not change how voltages are interpreted, but avoids
a false identification failure caused by mismatched mode
handling.
Fixes: f20b4a931130c ("hwmon: Add driver for MPS MPQ8785 Synchronous Step-Down Converter")
Signed-off-by: Carl Lee <carl.lee@amd.com>
Link: https://lore.kernel.org/r/20260210-dt-bindings-hwmon-pmbus-mpq8785-add-mpq8786-support-v3-1-84636ccfe76f@amd.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/pmbus/mpq8785.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/mpq8785.c b/drivers/hwmon/pmbus/mpq8785.c index 1f56aaf4dde8..87bd039c77b9 100644 --- a/drivers/hwmon/pmbus/mpq8785.c +++ b/drivers/hwmon/pmbus/mpq8785.c @@ -47,6 +47,33 @@ static int mpq8785_identify(struct i2c_client *client, return 0; }; +static int mpq8785_read_byte_data(struct i2c_client *client, int page, int reg) +{ + int ret; + + switch (reg) { + case PMBUS_VOUT_MODE: + ret = pmbus_read_byte_data(client, page, reg); + if (ret < 0) + return ret; + + if ((ret >> 5) == 1) { + /* + * The MPQ8785 chip reports VOUT_MODE as VID mode, but the driver + * treats VID as direct mode. Without this, identification would fail + * due to mode mismatch. + * This override ensures the reported mode matches the driver + * configuration, allowing successful initialization. + */ + return PB_VOUT_MODE_DIRECT; + } + + return ret; + default: + return -ENODATA; + } +} + static int mpm82504_read_word_data(struct i2c_client *client, int page, int phase, int reg) { @@ -129,6 +156,7 @@ static int mpq8785_probe(struct i2c_client *client) break; case mpq8785: info->identify = mpq8785_identify; + info->read_byte_data = mpq8785_read_byte_data; break; default: return -ENODEV; |