Re: [PATCH 1/5] hwmon: (pmbus/pim4328) Add function for reading direct mode coefficients

From: Guenter Roeck
Date: Wed May 19 2021 - 19:38:31 EST


On 5/19/21 1:10 PM, Erik Rosen wrote:
Add the function pmbus_read_coefficients to pmbus_core to be able to
read and decode the coefficients for the direct format for a certain
command and read/write direction.

Signed-off-by: Erik Rosen <erik.rosen@xxxxxxxxxxxxx>
---
drivers/hwmon/pmbus/pmbus.h | 4 ++++
drivers/hwmon/pmbus/pmbus_core.c | 38 ++++++++++++++++++++++++++++++++
2 files changed, 42 insertions(+)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index 3968924f8533..a131b253ebf9 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -499,6 +499,10 @@ int pmbus_get_fan_rate_cached(struct i2c_client *client, int page, int id,
enum pmbus_fan_mode mode);
int pmbus_update_fan(struct i2c_client *client, int page, int id,
u8 config, u8 mask, u16 command);
+int pmbus_read_coefficients(struct i2c_client *client,
+ struct pmbus_driver_info *info,
+ enum pmbus_sensor_classes sensor_class,
+ u8 command, bool for_reading);
struct dentry *pmbus_get_debugfs_dir(struct i2c_client *client);
#endif /* PMBUS_H */
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index bbd745178147..14d3d3352aac 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -301,6 +301,44 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id,
}
EXPORT_SYMBOL_NS_GPL(pmbus_update_fan, PMBUS);
+/*
+ * Read the coefficients for direct mode.
+ */
+int pmbus_read_coefficients(struct i2c_client *client,
+ struct pmbus_driver_info *info,
+ enum pmbus_sensor_classes sensor_class,
+ u8 command, bool for_reading)
+{

The way the code is written, we never need to read coefficients for writing.
With that in mind, I don't think the 'for_reading' parameter is necessary.

Guenter

+ int rv;
+ union i2c_smbus_data data;
+ s8 R;
+ s16 m, b;
+
+ data.block[0] = 2;
+ data.block[1] = command;
+ data.block[2] = for_reading ? 0x01 : 0x00;
+
+ 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[sensor_class] = m;
+ info->b[sensor_class] = b;
+ info->R[sensor_class] = R;
+
+ return rv;
+}
+EXPORT_SYMBOL_GPL(pmbus_read_coefficients);

EXPORT_SYMBOL_NS_GPL(pmbus_read_coefficients, PMBUS);

+
int pmbus_read_word_data(struct i2c_client *client, int page, int phase, u8 reg)
{
int rv;