Add support for reading and decoding direct format coefficients to
the PMBus core driver. If the new flag PMBUS_USE_COEFFICIENTS_CMD
is set, the driver will use the COEFFICIENTS register together with
the information in the pmbus_sensor_attr structs to initialize
relevant coefficients for the direct mode format.
Signed-off-by: Erik Rosen <erik.rosen@xxxxxxxxxxxxx>
---
drivers/hwmon/pmbus/pmbus_core.c | 116 +++++++++++++++++++++++++++++++
include/linux/pmbus.h | 8 +++
2 files changed, 124 insertions(+)
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index cb885efc4fba..cd80cb574267 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2139,6 +2139,111 @@ static int pmbus_find_attributes(struct i2c_client *client,
return ret;
}
+/*
+ * The pmbus_class_attr_map structure maps one sensor class to
+ * it's corresponding sensor attributes array.
+ */
+struct pmbus_class_attr_map {
+ enum pmbus_sensor_classes class;
+ int nattr;
+ const struct pmbus_sensor_attr *attr;
+};
+
+static const struct pmbus_class_attr_map class_attr_map[] = {
+ {
+ .class = PSC_VOLTAGE_IN,
+ .attr = voltage_attributes,
+ .nattr = ARRAY_SIZE(voltage_attributes),
+ }, {
+ .class = PSC_VOLTAGE_OUT,
+ .attr = voltage_attributes,
+ .nattr = ARRAY_SIZE(voltage_attributes),
+ }, {
+ .class = PSC_CURRENT_IN,
+ .attr = current_attributes,
+ .nattr = ARRAY_SIZE(current_attributes),
+ }, {
+ .class = PSC_CURRENT_OUT,
+ .attr = current_attributes,
+ .nattr = ARRAY_SIZE(current_attributes),
+ }, {
+ .class = PSC_POWER,
+ .attr = power_attributes,
+ .nattr = ARRAY_SIZE(power_attributes),
+ }, {
+ .class = PSC_TEMPERATURE,
+ .attr = temp_attributes,
+ .nattr = ARRAY_SIZE(temp_attributes),
+ }
+};
+
+/*
+ * Read the coefficients for direct mode.
+ */
+static int pmbus_read_coefficients(struct i2c_client *client,
+ struct pmbus_driver_info *info,
+ const struct pmbus_sensor_attr *attr)
+{
+ int rv;
+ union i2c_smbus_data data;
+ enum pmbus_sensor_classes class = attr->class;
+ s8 R;
+ s16 m, b;
+
+ data.block[0] = 2;
+ data.block[1] = attr->reg;
+ data.block[2] = 0x01;
+
+ rv = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
+ I2C_SMBUS_WRITE, PMBUS_COEFFICIENTS,
+ I2C_SMBUS_BLOCK_PROC_CALL, &data);
+
+ if (rv < 0)
+ return rv;
+
+ if (data.block[0] != 5)
+ return -EIO;
+
+ m = data.block[1] | (data.block[2] << 8);
+ b = data.block[3] | (data.block[4] << 8);
+ R = data.block[5];
+ info->m[class] = m;
+ info->b[class] = b;
+ info->R[class] = R;
+
+ return rv;
+}
+
+static int pmbus_init_coefficients(struct i2c_client *client,
+ struct pmbus_driver_info *info)
+{
+ int i, n, ret;
+ const struct pmbus_class_attr_map *map;
+ const struct pmbus_sensor_attr *attr;
+
+ for (i = 0; i < ARRAY_SIZE(class_attr_map); i++) {
+ map = &class_attr_map[i];
+ if (info->format[map->class] != direct)
+ continue;
+ for (n = 0; n < map->nattr; n++) {
+ attr = &map->attr[n];
+ if (map->class != attr->class)
+ continue;
+ ret = pmbus_read_coefficients(client, info, attr);
+ if (ret >= 0)
+ break;
+ }
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "No coefficients found for sensor class %d\n",
+ map->class);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
/*
* Identify chip parameters.
* This function is called for all chips.
@@ -2258,6 +2363,17 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
return ret;
}
}
+
+ if (data->flags & PMBUS_USE_COEFFICIENTS_CMD) {
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BLOCK_PROC_CALL))
+ return -ENODEV;
+
+ ret = pmbus_init_coefficients(client, info);
+ if (ret < 0)
+ return ret;
+ }
+
return 0;
}
diff --git a/include/linux/pmbus.h b/include/linux/pmbus.h
index f720470b1bab..7fdc282dab5a 100644
--- a/include/linux/pmbus.h
+++ b/include/linux/pmbus.h
@@ -52,6 +52,14 @@
*/
#define PMBUS_NO_WRITE_PROTECT BIT(4)
+/*
+ * PMBUS_USE_COEFFICIENTS_CMD
+ *
+ * When this flag is set the PMBus core driver will use the COEFFICIENTS
+ * register to initialize the coefficients for the direct mode format.
+ */
+#define PMBUS_USE_COEFFICIENTS_CMD BIT(5)
+
struct pmbus_platform_data {
u32 flags; /* Device specific flags */
--
2.20.1
