Re: [PATCH 3/7] hwmon: adm1275: Support ROHM BD12780
From: Guenter Roeck
Date: Tue Jun 16 2026 - 10:29:50 EST
On 6/15/26 23:36, Matti Vaittinen wrote:
From: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
ROHM BD12780 and BD12780A are hot-swap controllers. They are largely
similar to Analog Devices ADM1278. Besides the ID registers and some
added functionality, the BD12780 and BD12780A mark PMON_CONFIG bits
[15:14] as reserved. Hence TSFILT setting must be omitted on these ICs.
The BD12780 has 3 pins usable for configuring the I2C address. The
BD12780A lists the ADDR3-pin as "not connect".
Support ROHM BD12780 and BD12780A controllers.
Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
---
drivers/hwmon/pmbus/Kconfig | 2 +-
drivers/hwmon/pmbus/adm1275.c | 46 +++++++++++++++++++++++++++++------
2 files changed, 39 insertions(+), 9 deletions(-)
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 8f4bff375ecb..b3c27f3b2712 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -52,7 +52,7 @@ config SENSORS_ADM1275
help
If you say yes here you get hardware monitoring support for Analog
Devices ADM1075, ADM1272, ADM1273, ADM1275, ADM1276, ADM1278, ADM1281,
- ADM1293, ADM1294 and SQ24905C Hot-Swap Controller and
+ ADM1293, ADM1294, ROHM BD12780, and SQ24905C Hot-Swap Controller and
Digital Power Monitors.
This driver can also be built as a module. If so, the module will
diff --git a/drivers/hwmon/pmbus/adm1275.c b/drivers/hwmon/pmbus/adm1275.c
index bc2a6a07dc3e..838b8827eb76 100644
--- a/drivers/hwmon/pmbus/adm1275.c
+++ b/drivers/hwmon/pmbus/adm1275.c
@@ -19,7 +19,7 @@
#include "pmbus.h"
enum chips { adm1075, adm1272, adm1273, adm1275, adm1276, adm1278, adm1281,
- adm1293, adm1294, sq24905c };
+ adm1293, adm1294, bd12780, sq24905c };
#define ADM1275_MFR_STATUS_IOUT_WARN2 BIT(0)
#define ADM1293_MFR_STATUS_VAUX_UV_WARN BIT(5)
@@ -47,6 +47,8 @@ enum chips { adm1075, adm1272, adm1273, adm1275, adm1276, adm1278, adm1281,
#define ADM1278_VOUT_EN BIT(1)
#define ADM1278_PMON_DEFCONFIG (ADM1278_VOUT_EN | ADM1278_TEMP1_EN | ADM1278_TSFILT)
+/* The BD12780 data sheets mark TSFILT bit as reserved. */
+#define BD12780_PMON_DEFCONFIG (ADM1278_VOUT_EN | ADM1278_TEMP1_EN)
#define ADM1293_IRANGE_25 0
#define ADM1293_IRANGE_50 BIT(6)
@@ -487,6 +489,21 @@ static const struct i2c_device_id adm1275_id[] = {
{ "adm1281", adm1281 },
{ "adm1293", adm1293 },
{ "adm1294", adm1294 },
+ /*
+ * The BD12780a is functionally identical to BD12780(*). Even the pmbus ID
+ * register contents are same. When instantiated from the DT, it is required
+ * to have the bd12780 as a fall-back. We still need the bd12780a ID here,
+ * because the i2c_device_id is created from the first compatible, not from
+ * the fall-back entry.
+ * (*)Until proven to differ. I prefer having own compatible for these
+ * variants for that day. Please note that even though the probe is called
+ * based on the 'bd12780a' -entry, the ID is picked at probe based on the
+ * pmbus register contents and not by DT entry. Thus, if the bd12780 and
+ * bd12780a are found to require different handling, then this needs to be
+ * changed, or bd12780a is handled as bd12780.
+ */
+ { "bd12780", bd12780 },
+ { "bd12780a", /* driver data unused, see --^ */ },
We don't usually do that. There are various A/B/C variants for many chips,
and we just use the base name unless a difference is warranted. Either this
is needed, and driver data is needed as well, or it isn't. If it is not needed,
it should be dropped.
{ "mc09c", sq24905c },
{ }
};
@@ -494,12 +511,13 @@ MODULE_DEVICE_TABLE(i2c, adm1275_id);
/* Enable VOUT & TEMP1 if not enabled (disabled by default) */
static int adm1275_enable_vout_temp(struct adm1275_data *data,
- struct i2c_client *client, int config)
+ struct i2c_client *client, int config,
+ u16 defconfig)
{
int ret;
- if ((config & ADM1278_PMON_DEFCONFIG) != ADM1278_PMON_DEFCONFIG) {
- config |= ADM1278_PMON_DEFCONFIG;
+ if ((config & defconfig) != defconfig) {
+ config |= defconfig;
ret = adm1275_write_pmon_config(data, client, config);
if (ret < 0) {
dev_err(&client->dev, "Failed to enable VOUT/TEMP1 monitoring\n");
@@ -535,7 +553,8 @@ static int adm1275_probe(struct i2c_client *client)
return ret;
}
if ((ret != 3 || strncmp(block_buffer, "ADI", 3)) &&
- (ret != 2 || strncmp(block_buffer, "SY", 2))) {
+ (ret != 2 || strncmp(block_buffer, "SY", 2)) &&
+ (ret != 4 || strncmp(block_buffer, "ROHM", 4))) {
dev_err(&client->dev, "Unsupported Manufacturer ID\n");
return -ENODEV;
}
@@ -562,7 +581,7 @@ static int adm1275_probe(struct i2c_client *client)
if (mid->driver_data == adm1272 || mid->driver_data == adm1273 ||
mid->driver_data == adm1278 || mid->driver_data == adm1281 ||
mid->driver_data == adm1293 || mid->driver_data == adm1294 ||
- mid->driver_data == sq24905c)
+ mid->driver_data == bd12780 || mid->driver_data == sq24905c)
config_read_fn = i2c_smbus_read_word_data;
else
config_read_fn = i2c_smbus_read_byte_data;
@@ -666,7 +685,8 @@ static int adm1275_probe(struct i2c_client *client)
PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
- ret = adm1275_enable_vout_temp(data, client, config);
+ ret = adm1275_enable_vout_temp(data, client, config,
+ ADM1278_PMON_DEFCONFIG);
if (ret)
return ret;
@@ -712,7 +732,16 @@ static int adm1275_probe(struct i2c_client *client)
break;
case adm1278:
case adm1281:
+ case bd12780:
case sq24905c:
+ {
+ u16 defconfig;
+
+ if (data->id == bd12780)
+ defconfig = BD12780_PMON_DEFCONFIG;
+ else
+ defconfig = ADM1278_PMON_DEFCONFIG;
+
Please add a separate case statement for the new chip
and do not overload existing chip data.
data->have_vout = true;
data->have_pin_max = true;
data->have_temp_max = true;
@@ -728,13 +757,14 @@ static int adm1275_probe(struct i2c_client *client)
PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
- ret = adm1275_enable_vout_temp(data, client, config);
+ ret = adm1275_enable_vout_temp(data, client, config, defconfig);
if (ret)
return ret;
if (config & ADM1278_VIN_EN)
info->func[0] |= PMBUS_HAVE_VIN;
break;
+ }
case adm1293:
case adm1294:
data->have_iout_min = true;