> -----Original Message-----
> From: Guenter Roeck <groeck7@xxxxxxxxx> On Behalf Of Guenter Roeck
> Sent: Monday, May 10, 2021 7:48 PM
> To: Vadim Pasternak <vadimp@xxxxxxxxxx>
> Cc: robh+dt@xxxxxxxxxx; linux-hwmon@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH hwmon-next v6 2/3] hwmon: (pmbus) Add support for
> MPS Multi-phase mp2888 controller
>
> On Fri, May 07, 2021 at 08:14:20PM +0300, Vadim Pasternak wrote:
> > Add support for mp2888 device from Monolithic Power Systems, Inc.
> > (MPS) vendor. This is a digital, multi-phase, pulse-width modulation
> > controller.
> >
> > This device supports:
> > - One power rail.
> > - Programmable Multi-Phase up to 10 Phases.
> > - PWM-VID Interface
> > - One pages 0 for telemetry.
> > - Programmable pins for PMBus Address.
> > - Built-In EEPROM to Store Custom Configurations.
> > - Can configured VOUT readout in direct or VID format and allows
> > setting of different formats on rails 1 and 2. For VID the following
> > protocols are available: VR13 mode with 5-mV DAC; VR13 mode with
> > 10-mV DAC, IMVP9 mode with 5-mV DAC.
> >
> > Signed-off-by: Vadim Pasternak <vadimp@xxxxxxxxxx>
> > ---
> > v5->v6
> > Comments pointed out by Guenter:
> > - Fix comments for limits in mp2888_read_word_data().
> > - Remove unnecessary typecasts from mp2888_write_word_data().
> >
> > v4->v5
> > Comments pointed out by Guenter:
> > - Fix calculation of PMBUS_READ_VIN.
> > - Add mp2888_write_word_data() for limits setting.
> > - Treat PMBUS_POUT_OP_WARN_LIMIT in separate case.
> > - Drop tuning of "m[PSC_POWER]" and "m[PSC_CURRENT_OUT]" from
> probing
> > routine.
> > Fixes from Vadim:
> > - Treat PMBUS_IOUT_OC_WARN_LIMIT in separate case.
> >
> > v3->v4
> > Comments pointed out by Guenter:
> > - Fix PMBUS_READ_VIN and limits calculations.
> > - Add comment for PMBUS_OT_WARN_LIMIT scaling.
> > - Fix PMBUS_READ_IOUT, PMBUS_READ_POUT, PMBUS_READ_PIN
> calculations.
> > - Enable PMBUS_IOUT_OC_WARN_LIMIT and
> PMBUS_POUT_OP_WARN_LIMIT.
> > Fixes from Vadim:
> > - Disable PMBUS_POUT_MAX. Device uses this register for different
> > purpose.
> > - Disable PMBUS_MFR_VOU_MIN. Device doe not implement this
> register.
> > - Update documentation file.
> >
> > v2->v3
> > Comments pointed out by Guenter:
> > - Fix precision for PMBUS_READ_VIN (it requires adding scale for
> > PMBUS_VIN_OV_FAULT_LIMIT and PMBUS_VIN_UV_WARN_LIMIT.
> > - Fix precision for PMBUS_READ_TEMPERATURE_1 (it requires adding
> > scale for PMBUS_OT_WARN_LIMIT).
> > - Use DIV_ROUND_CLOSEST_ULL for scaling PMBUS_READ_POUT,
> > PMBUS_READ_PIN readouts.
> > Notes and fixes from Vadim:
> > - READ_IOUT in linear11 does not give write calculation (tested with
> > external load), while in direct format readouts are correct.
> > - Disable non-configured phases in mp2888_identify_multiphase().
> >
> > v1->v2:
> > Comments pointed out by Guenter:
> > - Use standard access for getting PMBUS_OT_WARN_LIMIT,
> > PMBUS_VIN_OV_FAULT_LIMIT, PMBUS_VIN_UV_WARN_LIMIT.
> > - Use linear11 conversion for PMBUS_READ_VIN, PMBUS_READ_POUT,
> > PMBUS_READ_PIN, PMBUS_READ_TEMPERATURE_1 and adjust
> coefficients.
> > - Add reading phases current from the dedicated registers.
> > - Add comment for not implemented or implemented not according to the
> > spec registers, for which "ENXIO" code is returned.
> > - Set PMBUS_HAVE_IOUT" statically.
> > Notes from Vadim:
> > - READ_IOUT uses direct format, so I did not adjust it like the below
> > registers.
> > ---
>
> [ ... ]
>
> > +
> > +static int mp2888_write_word_data(struct i2c_client *client, int
> > +page, int reg, u16 word) {
> > + const struct pmbus_driver_info *info =
> pmbus_get_driver_info(client);
> > + struct mp2888_data *data = to_mp2888_data(info);
> > +
> > + switch (reg) {
> > + case PMBUS_OT_WARN_LIMIT:
> > + word = DIV_ROUND_CLOSEST((int)word,
> MP2888_TEMP_UNIT);
>
> Sorry if I am missing something, but why those typecasts here and below ?
I forgot to remove it. Sorry.
>
> > + /* Drop unused bits 15:8. */
> > + word = clamp_val(word, 0, GENMASK(7, 0));
> > + break;
> > + case PMBUS_IOUT_OC_WARN_LIMIT:
> > + /* Fix limit according to total curent resolution. */
> > + word = data->total_curr_resolution ?
> DIV_ROUND_CLOSEST((int)word, 8) :
> > + DIV_ROUND_CLOSEST((int)word, 4);
> > + /* Drop unused bits 15:10. */
> > + word = clamp_val(word, 0, GENMASK(9, 0));
> > + break;
> > + case PMBUS_POUT_OP_WARN_LIMIT:
> > + /* Fix limit according to total curent resolution. */
> > + word = data->total_curr_resolution ?
> DIV_ROUND_CLOSEST((int)word, 4) :
> > + DIV_ROUND_CLOSEST((int)word, 2);
> > + /* Drop unused bits 15:10. */
> > + word = clamp_val(word, 0, GENMASK(9, 0));
> > + break;
> > + default:
> > + return -ENODATA;
> > + }
> > + return pmbus_write_word_data(client, page, reg, word); }
> > +
> > +static int
> > +mp2888_identify_multiphase(struct i2c_client *client, struct mp2888_data
> *data,
> > + struct pmbus_driver_info *info) {
> > + int i, ret;
> > +
> > + ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
> > + if (ret < 0)
> > + return ret;
> > +
> > + /* Identify multiphase number - could be from 1 to 10. */
> > + ret = i2c_smbus_read_word_data(client,
> MP2888_MFR_VR_CONFIG1);
> > + if (ret <= 0)
> > + return ret;
> > +
> > + info->phases[0] = ret & GENMASK(3, 0);
> > +
> > + /*
> > + * The device provides a total of 10 PWM pins, and can be configured
> to different phase
> > + * count applications for rail.
> > + */
> > + if (info->phases[0] > MP2888_MAX_PHASE)
> > + return -EINVAL;
> > +
> > + /* Disable non-configured phases. */
> > + for (i = info->phases[0]; i < MP2888_MAX_PHASE; i++)
> > + info->pfunc[i] = 0;
>
> Not that it matters much, but this is unnecessary since the pmbus core won't
> look at phase data beyond info->phases[].
I see. So I'll drop these two lines.
>
> Guenter
