On Thu, May 13, 2021 at 10:11:10PM +0200, Václav Kubernát wrote:
> After testing new YH-5151E devices, we found out that not all YH-5151E
> work the same. The newly tested devices actually report vout correctly
> in linear16 (even though they're still YH-5151E). We suspect that it is
> because these new devices have a different firmware version, but that is
> unconfirmed. The version cannot be queried through PMBus.
>
> The compliant versions of YH-5151E report VOUT_MODE normally, so we turn
> on the linear11 workaround only if VOUT_MODE doesn't report anything.
>
What a mess. But thanks for keeping on top of this, and for the fix.
Applied.
Thanks,
Guenter
> Signed-off-by: Václav Kubernát <kubernat@xxxxxxxxx>
> ---
> drivers/hwmon/pmbus/fsp-3y.c | 32 +++++++++++++++++++++++++-------
> 1 file changed, 25 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/hwmon/pmbus/fsp-3y.c b/drivers/hwmon/pmbus/fsp-3y.c
> index 46252b17c008..073d960a0af5 100644
> --- a/drivers/hwmon/pmbus/fsp-3y.c
> +++ b/drivers/hwmon/pmbus/fsp-3y.c
> @@ -37,6 +37,8 @@ struct fsp3y_data {
> struct pmbus_driver_info info;
> int chip;
> int page;
> +
> + bool vout_linear_11;
> };
>
> #define to_fsp3y_data(x) container_of(x, struct fsp3y_data, info)
> @@ -108,11 +110,9 @@ static int fsp3y_read_byte_data(struct i2c_client *client, int page, int reg)
> int rv;
>
> /*
> - * YH5151-E outputs vout in linear11. The conversion is done when
> - * reading. Here, we have to inject pmbus_core with the correct
> - * exponent (it is -6).
> + * Inject an exponent for non-compliant YH5151-E.
> */
> - if (data->chip == yh5151e && reg == PMBUS_VOUT_MODE)
> + if (data->vout_linear_11 && reg == PMBUS_VOUT_MODE)
> return 0x1A;
>
> rv = set_page(client, page);
> @@ -161,10 +161,9 @@ static int fsp3y_read_word_data(struct i2c_client *client, int page, int phase,
> return rv;
>
> /*
> - * YH-5151E is non-compliant and outputs output voltages in linear11
> - * instead of linear16.
> + * Handle YH-5151E non-compliant linear11 vout voltage.
> */
> - if (data->chip == yh5151e && reg == PMBUS_READ_VOUT)
> + if (data->vout_linear_11 && reg == PMBUS_READ_VOUT)
> rv = sign_extend32(rv, 10) & 0xffff;
>
> return rv;
> @@ -256,6 +255,25 @@ static int fsp3y_probe(struct i2c_client *client)
>
> data->info = fsp3y_info[data->chip];
>
> + /*
> + * YH-5151E sometimes reports vout in linear11 and sometimes in
> + * linear16. This depends on the exact individual piece of hardware. One
> + * YH-5151E can use linear16 and another might use linear11 instead.
> + *
> + * The format can be recognized by reading VOUT_MODE - if it doesn't
> + * report a valid exponent, then vout uses linear11. Otherwise, the
> + * device is compliant and uses linear16.
> + */
> + data->vout_linear_11 = false;
> + if (data->chip == yh5151e) {
> + rv = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
> + if (rv < 0)
> + return rv;
> +
> + if (rv == 0xFF)
> + data->vout_linear_11 = true;
> + }
> +
> return pmbus_do_probe(client, &data->info);
> }
>
