On 4/28/21 1:38 AM, Václav Kubernát wrote:
> I didn't properly test the driver for YH-5151E, so it was completely
> broken. Firstly, the log/real mapping was incorrect in one case.
> Secondly, PMBus specifies that output voltages should be in the linear16
> encoding. However, the PDU is non-compliant and uses linear11. YM-2151E
> isn't affected by this. Fix this by converting the values inside the
> read functions. linear16 gets the exponent from the VOUT_MODE command.
> The device doesn't support it, so I have to manually supply the value
> for it.
>
> Both supported devices have now been tested to report correct vout
> values.
>
Fixes: 1734b4135a62 ("hwmon: Add driver for fsp-3y PSUs and PDUs")
> Signed-off-by: Václav Kubernát <kubernat@xxxxxxxxx>
> ---
> drivers/hwmon/pmbus/fsp-3y.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwmon/pmbus/fsp-3y.c b/drivers/hwmon/pmbus/fsp-3y.c
> index 564649e87e34..dc147a79d6aa 100644
> --- a/drivers/hwmon/pmbus/fsp-3y.c
> +++ b/drivers/hwmon/pmbus/fsp-3y.c
> @@ -57,7 +57,7 @@ static int page_log_to_page_real(int page_log, enum chips chip)
> case YH5151E_PAGE_12V_LOG:
> return YH5151E_PAGE_12V_REAL;
> case YH5151E_PAGE_5V_LOG:
> - return YH5151E_PAGE_5V_LOG;
> + return YH5151E_PAGE_5V_REAL;
> case YH5151E_PAGE_3V3_LOG:
> return YH5151E_PAGE_3V3_REAL;
> }
> @@ -103,17 +103,28 @@ static int set_page(struct i2c_client *client, int page_log)
>
> static int fsp3y_read_byte_data(struct i2c_client *client, int page, int reg)
> {
> + const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> + struct fsp3y_data *data = to_fsp3y_data(info);
> int rv;
>
> rv = set_page(client, page);
> if (rv < 0)
> return rv;
>
> + /*
> + * YH5151-E outputs vout in linear11. The conversion is done later, but
> + * I have to inject pmbus_core with the correct exponent.
s/I/we/
Also, it might be useful to mention the actual exponent (-6 ?) in the comment.
> + */
> + if (data->chip == yh5151e && reg == PMBUS_VOUT_MODE)
> + return 0x1A;
Can this code be moved ahead of set_page() ?
> +
> return i2c_smbus_read_byte_data(client, reg);
> }
>
> static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase, int reg)
> {
> + const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> + struct fsp3y_data *data = to_fsp3y_data(info);
> int rv;
>
> /*
> @@ -144,7 +155,18 @@ static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase,
> if (rv < 0)
> return rv;
>
> - return i2c_smbus_read_word_data(client, reg);
> + rv = i2c_smbus_read_word_data(client, reg);
> + if (rv < 0)
> + return rv;
> +
> + /*
> + * The PDU is non-compliant and outputs output voltages in linear11
s/The PDU/YH-5151E/
> + * instead of linear16.
> + */
> + if (data->chip == yh5151e && reg == PMBUS_READ_VOUT)
> + rv = ((s16)((rv & 0x7ff) << 5)) >> 5;
Problem with this is that it auto-converts to int and will return a
negative value if bit 10 is set (I wrote some test code and confirmed it,
just to be sure).
rv = sign_extend32(rv, 10) & 0xffff;
should work here.
Thanks,
Guenter
> +
> + return rv;
> }
>
> struct pmbus_driver_info fsp3y_info[] = {
>
