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References: <20230712114754.500477-1-Naresh.Solanki@9elements.com>
 <20230712114754.500477-6-Naresh.Solanki@9elements.com> <76aa2aa3-1d38-36a2-d664-00b719f37932@roeck-us.net>
In-Reply-To: <76aa2aa3-1d38-36a2-d664-00b719f37932@roeck-us.net>
From:   Naresh Solanki <naresh.solanki@9elements.com>
Date:   Fri, 14 Jul 2023 14:25:02 +0200
Message-ID: <CABqG17i5NrxAxAxvd3FkLt7_yjw7Zy_usFZiVnPTduh1D3c8JQ@mail.gmail.com>
Subject: Re: [PATCH 6/8] hwmon: (pmbus/mp2975) Add support for MP2971 and MP2973
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     devicetree@vger.kernel.org, Jean Delvare <jdelvare@suse.com>,
        linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
        Patrick Rudolph <patrick.rudolph@9elements.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Guenter,


On Wed, 12 Jul 2023 at 19:58, Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 7/12/23 04:47, Naresh Solanki wrote:
> > From: Patrick Rudolph <patrick.rudolph@9elements.com>
> >
> > Add support for MP2971 and MP2973, the successor of MP2975.
> >
> > The major differences are:
> >   - On MP2973 and MP2971 the Vref cannot be read and thus most of
> >     the OVP/current calculations won't work.
> >   - MP2973 and MP2971 also support LINEAR format for VOUT
> >   - MP2973 and MP2971 do not support OVP2
> >   - On MP2973 and MP2971 most registers are in LINEAR format
> >   - The IMVP9_EN bit has a different position
> >   - Per phase current sense haven't been implemented.
> >
> > As on MP2975 most of the FAULT_LIMIT and WARN_LIMIT registers
> > have been redefined and doesn't provide the functionality as
> > defined in PMBUS spec.
> >
> > Tested on MP2973 and MP2971.
> >
> > Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> > Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> > ---
> >   drivers/hwmon/pmbus/mp2975.c | 262 +++++++++++++++++++++++++++++------
> >   1 file changed, 221 insertions(+), 41 deletions(-)
> >
> > diff --git a/drivers/hwmon/pmbus/mp2975.c b/drivers/hwmon/pmbus/mp2975.c
> > index 13d8b95eb992..83242595ccbe 100644
> > --- a/drivers/hwmon/pmbus/mp2975.c
> > +++ b/drivers/hwmon/pmbus/mp2975.c
> > @@ -35,6 +35,8 @@
> >   #define MP2975_MFR_OVP_TH_SET               0xe5
> >   #define MP2975_MFR_UVP_SET          0xe6
> >
> > +#define MP2973_MFR_RESO_SET          0xc7
> > +
> >   #define MP2975_VOUT_FORMAT          BIT(15)
> >   #define MP2975_VID_STEP_SEL_R1              BIT(4)
> >   #define MP2975_IMVP9_EN_R1          BIT(13)
> > @@ -49,8 +51,32 @@
> >   #define MP2975_SENSE_AMPL_HALF              2
> >   #define MP2975_VIN_UV_LIMIT_UNIT    8
> >
> > +#define MP2973_VOUT_FORMAT_R1                GENMASK(7, 6)
> > +#define MP2973_VOUT_FORMAT_R2                GENMASK(4, 3)
> > +#define MP2973_VOUT_FORMAT_DIRECT_R1 BIT(7)
> > +#define MP2973_VOUT_FORMAT_LINEAR_R1 BIT(6)
> > +#define MP2973_VOUT_FORMAT_DIRECT_R2 BIT(4)
> > +#define MP2973_VOUT_FORMAT_LINEAR_R2 BIT(3)
> > +
> > +#define MP2973_MFR_VR_MULTI_CONFIG_R1        0x0d
> > +#define MP2973_MFR_VR_MULTI_CONFIG_R2        0x1d
> > +#define MP2973_VID_STEP_SEL_R1               BIT(4)
> > +#define MP2973_IMVP9_EN_R1           BIT(14)
> > +#define MP2973_VID_STEP_SEL_R2               BIT(3)
> > +#define MP2973_IMVP9_EN_R2           BIT(13)
> > +
> > +#define MP2973_MFR_READ_IOUT_PK              0x90
> > +#define MP2973_MFR_READ_POUT_PK              0x91
> > +
> >   #define MP2975_MAX_PHASE_RAIL1      8
> >   #define MP2975_MAX_PHASE_RAIL2      4
> > +
> > +#define MP2973_MAX_PHASE_RAIL1       14
> > +#define MP2973_MAX_PHASE_RAIL2       6
> > +
> > +#define MP2971_MAX_PHASE_RAIL1       8
> > +#define MP2971_MAX_PHASE_RAIL2       3
> > +
> >   #define MP2975_PAGE_NUM             2
> >
> >   #define MP2975_RAIL2_FUNC   (PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | \
> > @@ -58,11 +84,13 @@
> >                                PMBUS_HAVE_POUT | PMBUS_PHASE_VIRTUAL)
> >
> >   enum chips {
> > -     mp2975
> > +     mp2971, mp2973, mp2975
> >   };
> >
> >   static const int mp2975_max_phases[][MP2975_PAGE_NUM] = {
> >       [mp2975] = { MP2975_MAX_PHASE_RAIL1, MP2975_MAX_PHASE_RAIL2 },
> > +     [mp2973] = { MP2973_MAX_PHASE_RAIL1, MP2973_MAX_PHASE_RAIL2 },
> > +     [mp2971] = { MP2971_MAX_PHASE_RAIL1, MP2971_MAX_PHASE_RAIL2 },
> >   };
> >
> >   struct mp2975_data {
> > @@ -79,6 +107,8 @@ struct mp2975_data {
> >   };
> >
> >   static const struct i2c_device_id mp2975_id[] = {
> > +     {"mp2971", mp2971},
> > +     {"mp2973", mp2973},
> >       {"mp2975", mp2975},
> >       {}
> >   };
> > @@ -215,6 +245,76 @@ mp2975_read_phases(struct i2c_client *client, struct mp2975_data *data,
> >       return ret;
> >   }
> >
> > +static int mp2973_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 mp2975_data *data = to_mp2975_data(info);
> > +     int ret;
> > +
> > +     switch (reg) {
> > +     case PMBUS_OT_FAULT_LIMIT:
> > +             ret = mp2975_read_word_helper(client, page, phase, reg,
> > +                                           GENMASK(7, 0));
> > +             break;
> > +     case PMBUS_VIN_OV_FAULT_LIMIT:
> > +             ret = mp2975_read_word_helper(client, page, phase, reg,
> > +                                           GENMASK(7, 0));
> > +             if (ret < 0)
> > +                     return ret;
> > +
> > +             ret = DIV_ROUND_CLOSEST(ret, MP2975_VIN_UV_LIMIT_UNIT);
> > +             break;
> > +     case PMBUS_VOUT_OV_FAULT_LIMIT:
> > +             /*
> > +              * MP2971 and mp2973 only supports tracking (ovp1) mode.
> > +              */
> > +             ret = mp2975_read_word_helper(client, page, phase,
> > +                                           MP2975_MFR_OVP_TH_SET,
> > +                                           GENMASK(2, 0));
> > +             if (ret < 0)
> > +                     return ret;
> > +
> > +             ret = data->vout_max[page] + 50 * (ret + 1);
> > +             break;
> > +     case PMBUS_VOUT_UV_FAULT_LIMIT:
> > +             ret = mp2975_read_word_helper(client, page, phase, reg,
> > +                                           GENMASK(8, 0));
> > +             if (ret < 0)
> > +                     return ret;
> > +             ret = mp2975_vid2direct(info->vrm_version[page], ret);
> > +             break;
> > +     case PMBUS_VIRT_READ_POUT_MAX:
> > +             ret = pmbus_read_word_data(client, page, phase,
> > +                                        MP2973_MFR_READ_POUT_PK);
> > +             break;
> > +     case PMBUS_VIRT_READ_IOUT_MAX:
> > +             ret = pmbus_read_word_data(client, page, phase,
> > +                                        MP2973_MFR_READ_IOUT_PK);
> > +             break;
> > +     case PMBUS_UT_WARN_LIMIT:
> > +     case PMBUS_UT_FAULT_LIMIT:
> > +     case PMBUS_VIN_UV_WARN_LIMIT:
> > +     case PMBUS_VIN_UV_FAULT_LIMIT:
> > +     case PMBUS_VOUT_UV_WARN_LIMIT:
> > +     case PMBUS_VOUT_OV_WARN_LIMIT:
> > +     case PMBUS_VIN_OV_WARN_LIMIT:
> > +     case PMBUS_IIN_OC_FAULT_LIMIT:
> > +     case PMBUS_IOUT_OC_LV_FAULT_LIMIT:
> > +     case PMBUS_IOUT_OC_WARN_LIMIT:
> > +     case PMBUS_IOUT_OC_FAULT_LIMIT:
> > +     case PMBUS_IOUT_UC_FAULT_LIMIT:
> > +     case PMBUS_POUT_OP_FAULT_LIMIT:
> > +     case PMBUS_POUT_OP_WARN_LIMIT:
> > +     case PMBUS_PIN_OP_WARN_LIMIT:
> > +             return -ENXIO;
> > +     default:
> > +             return -ENODATA;
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> >   static int mp2975_read_word_data(struct i2c_client *client, int page,
> >                                int phase, int reg)
> >   {
> > @@ -386,7 +486,7 @@ mp2975_identify_multiphase(struct i2c_client *client, struct mp2975_data *data,
> >   }
> >
> >   static int
> > -mp2975_identify_vid(struct i2c_client *client, struct mp2975_data *data,
> > +mp297x_identify_vid(struct i2c_client *client, struct mp2975_data *data,
>
> Please refrain from such cosmetic changes. It is perfectly fine to keep
> calling the function mp2975_identify_vid() even if it is called for
> other chips.
>
> Those changes only make it more difficult to review your patch and,
> on top of that, are not really related to introducing support for
> the new chips.
Yes. I agree with you.
I've removed cosmetic changes & diff looks better now.
Will follow this way for future patch.
Thanks.
>
> >                   struct pmbus_driver_info *info, u32 reg, int page,
> >                   u32 imvp_bit, u32 vr_bit)
> >   {
> > @@ -422,7 +522,7 @@ mp2975_identify_rails_vid(struct i2c_client *client, struct mp2975_data *data,
> >               return ret;
> >
> >       /* Identify VID mode for rail 1. */
> > -     ret = mp2975_identify_vid(client, data, info,
> > +     ret = mp297x_identify_vid(client, data, info,
> >                                 MP2975_MFR_VR_MULTI_CONFIG_R1, 0,
> >                                 MP2975_IMVP9_EN_R1, MP2975_VID_STEP_SEL_R1);
> >       if (ret < 0)
> > @@ -430,10 +530,39 @@ mp2975_identify_rails_vid(struct i2c_client *client, struct mp2975_data *data,
> >
> >       /* Identify VID mode for rail 2, if connected. */
> >       if (info->phases[1])
> > -             ret = mp2975_identify_vid(client, data, info,
> > +             ret = mp297x_identify_vid(client, data, info,
> >                                         MP2975_MFR_VR_MULTI_CONFIG_R2, 1,
> >                                         MP2975_IMVP9_EN_R2,
> >                                         MP2975_VID_STEP_SEL_R2);
> > +
> > +     return ret;
> > +}
> > +
> > +static int
> > +mp2973_identify_rails_vid(struct i2c_client *client, struct mp2975_data *data,
> > +                       struct pmbus_driver_info *info)
> > +{
> > +     int ret;
> > +
> > +     ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 2);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     /* Identify VID mode for rail 1. */
> > +     ret = mp297x_identify_vid(client, data, info,
> > +                               MP2973_MFR_VR_MULTI_CONFIG_R1, 0,
> > +                               MP2973_IMVP9_EN_R1, MP2973_VID_STEP_SEL_R1);
> > +
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     /* Identify VID mode for rail 2, if connected. */
> > +     if (info->phases[1])
> > +             ret = mp297x_identify_vid(client, data, info,
> > +                                       MP2973_MFR_VR_MULTI_CONFIG_R2, 1,
> > +                                       MP2973_IMVP9_EN_R2,
> > +                                       MP2973_VID_STEP_SEL_R2);
> > +
> >       return ret;
> >   }
> >
> > @@ -532,7 +661,7 @@ mp2975_vref_offset_get(struct i2c_client *client, struct mp2975_data *data,
> >   }
> >
> >   static int
> > -mp2975_vout_max_get(struct i2c_client *client, struct mp2975_data *data,
> > +mp297x_vout_max_get(struct i2c_client *client, struct mp2975_data *data,
> >                   struct pmbus_driver_info *info, int page)
> >   {
> >       int ret;
> > @@ -548,17 +677,33 @@ mp2975_vout_max_get(struct i2c_client *client, struct mp2975_data *data,
> >   }
> >
> >   static int
> > -mp2975_set_vout_format(struct i2c_client *client,
> > +mp297x_set_vout_format(struct i2c_client *client,
> >                      struct mp2975_data *data, int page)
> >   {
> >       int ret;
> >
> > -     ret = i2c_smbus_read_word_data(client, MP2975_MFR_DC_LOOP_CTRL);
> > -     if (ret < 0)
> > -             return ret;
> >       /* Enable DIRECT VOUT format 1mV/LSB */
> > -     ret &= ~MP2975_VOUT_FORMAT;
> > -     ret = i2c_smbus_write_word_data(client, MP2975_MFR_DC_LOOP_CTRL, ret);
> > +     if (data->chip_id == mp2975) {
> > +             ret = i2c_smbus_read_word_data(client, MP2975_MFR_DC_LOOP_CTRL);
> > +             if (ret < 0)
> > +                     return ret;
> > +             ret &= ~MP2975_VOUT_FORMAT;
> > +             ret = i2c_smbus_write_word_data(client, MP2975_MFR_DC_LOOP_CTRL, ret);
> > +     } else {
> > +             ret = i2c_smbus_read_word_data(client, MP2973_MFR_RESO_SET);
> > +             if (ret < 0)
> > +                     return ret;
> > +
> > +             if (page == 0) {
> > +                     ret &= ~MP2973_VOUT_FORMAT_R1;
> > +                     ret |= MP2973_VOUT_FORMAT_DIRECT_R1;
> > +             } else {
> > +                     ret &= ~MP2973_VOUT_FORMAT_R2;
> > +                     ret |= MP2973_VOUT_FORMAT_DIRECT_R2;
> > +             }
> > +
> > +             ret = i2c_smbus_write_word_data(client, MP2973_MFR_RESO_SET, ret);
>
> Same as with the previous patch: The value only needs to be written back if it differs
> from the value already configured in the chip.
Yes. I that's efficient approach.
Will introduce a variable 'i' & check for difference at the end & do
i2c write if needed.

>
> > +     }
> >       return ret;
> >   }
> >
> > @@ -605,24 +750,28 @@ mp2975_vout_per_rail_config_get(struct i2c_client *client,
> >       for (i = 0; i < data->info.pages; i++) {
> >               ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
> >               if (ret < 0)
> > -                     return ret;
> > +                     continue;
> >
> > -             /* Obtain voltage reference offsets. */
> > -             ret = mp2975_vref_offset_get(client, data, i);
> > +             /*
> > +              * Set VOUT format for READ_VOUT command : direct.
> > +              * Pages on same device can be configured with different
> > +              * formats.
> > +              */
> > +             ret = mp297x_set_vout_format(client, data, i);
> >               if (ret < 0)
> >                       return ret;
> >
> >               /* Obtain maximum voltage values. */
> > -             ret = mp2975_vout_max_get(client, data, info, i);
> > +             ret = mp297x_vout_max_get(client, data, info, i);
> >               if (ret < 0)
> >                       return ret;
> >
> > -             /*
> > -              * Set VOUT format for READ_VOUT command : direct.
> > -              * Pages on same device can be configured with different
> > -              * formats.
> > -              */
> > -             ret = mp2975_set_vout_format(client, data, i);
> > +             /* Skip if reading Vref is unsupported */
> > +             if (data->chip_id != mp2975)
> > +                     continue;
> > +
> > +             /* Obtain voltage reference offsets. */
> > +             ret = mp2975_vref_offset_get(client, data, i);
> >               if (ret < 0)
> >                       return ret;
> >
> > @@ -660,6 +809,23 @@ static struct pmbus_driver_info mp2975_info = {
> >       .read_word_data = mp2975_read_word_data,
> >   };
> >
> > +static struct pmbus_driver_info mp2973_info = {
> > +     .pages = 1,
> > +     .format[PSC_VOLTAGE_IN] = linear,
> > +     .format[PSC_VOLTAGE_OUT] = direct,
> > +     .format[PSC_TEMPERATURE] = linear,
> > +     .format[PSC_CURRENT_IN] = linear,
> > +     .format[PSC_CURRENT_OUT] = linear,
> > +     .format[PSC_POWER] = linear,
> > +     .m[PSC_VOLTAGE_OUT] = 1,
> > +     .R[PSC_VOLTAGE_OUT] = 3,
> > +     .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
> > +             PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
> > +             PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_POUT |
> > +             PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT,
> > +     .read_word_data = mp2973_read_word_data,
> > +};
> > +
> >   static int mp2975_probe(struct i2c_client *client)
> >   {
> >       struct pmbus_driver_info *info;
> > @@ -679,6 +845,11 @@ static int mp2975_probe(struct i2c_client *client)
> >       memcpy(data->max_phases, mp2975_max_phases[data->chip_id],
> >              sizeof(data->max_phases));
> >
> > +     if (data->chip_id == mp2975)
> > +             memcpy(&data->info, &mp2975_info, sizeof(*info));
> > +     else
> > +             memcpy(&data->info, &mp2973_info, sizeof(*info));
> > +
> >       info = &data->info;
> >
> >       /* Identify multiphase configuration for rail 2. */
> > @@ -693,30 +864,37 @@ static int mp2975_probe(struct i2c_client *client)
> >               data->info.func[1] = MP2975_RAIL2_FUNC;
> >       }
> >
> > -     /* Identify multiphase configuration. */
> > -     ret = mp2975_identify_multiphase(client, data, info);
> > -     if (ret)
> > -             return ret;
> > +     if (data->chip_id == mp2975) {
> > +             /* Identify multiphase configuration. */
> > +             ret = mp2975_identify_multiphase(client, data, info);
> > +             if (ret)
> > +                     return ret;
> >
> > -     /* Identify VID setting per rail. */
> > -     ret = mp2975_identify_rails_vid(client, data, info);
> > -     if (ret < 0)
> > -             return ret;
> > +             /* Identify VID setting per rail. */
> > +             ret = mp2975_identify_rails_vid(client, data, info);
> > +             if (ret < 0)
> > +                     return ret;
> >
> > -     /* Obtain current sense gain of power stage. */
> > -     ret = mp2975_current_sense_gain_get(client, data);
> > -     if (ret)
> > -             return ret;
> > +             /* Obtain current sense gain of power stage. */
> > +             ret = mp2975_current_sense_gain_get(client, data);
> > +             if (ret)
> > +                     return ret;
> >
> > -     /* Obtain voltage reference values. */
> > -     ret = mp2975_vref_get(client, data, info);
> > -     if (ret)
> > -             return ret;
> > +             /* Obtain voltage reference values. */
> > +             ret = mp2975_vref_get(client, data, info);
> > +             if (ret)
> > +                     return ret;
> >
> > -     /* Obtain vout over-voltage scales. */
> > -     ret = mp2975_vout_ov_scale_get(client, data, info);
> > -     if (ret < 0)
> > -             return ret;
> > +             /* Obtain vout over-voltage scales. */
> > +             ret = mp2975_vout_ov_scale_get(client, data, info);
> > +             if (ret < 0)
> > +                     return ret;
> > +     } else {
> > +             /* Identify VID setting per rail. */
> > +             ret = mp2973_identify_rails_vid(client, data, info);
> > +             if (ret < 0)
> > +                     return ret;
> > +     }
> >
> >       /* Obtain offsets, maximum and format for vout. */
> >       ret = mp2975_vout_per_rail_config_get(client, data, info);
> > @@ -727,6 +905,8 @@ static int mp2975_probe(struct i2c_client *client)
> >   }
> >
> >   static const struct of_device_id __maybe_unused mp2975_of_match[] = {
> > +     {.compatible = "mps,mp2971", .data = (void *)mp2971},
> > +     {.compatible = "mps,mp2973", .data = (void *)mp2973},
> >       {.compatible = "mps,mp2975", .data = (void *)mp2975},
> >       {}
> >   };
>