Re: [PATCH v5 09/11] mfd: bq257xx: Add BQ25792 support

[Alexey Charkov]

On Tue, Mar 31, 2026 at 2:27 PM Lee Jones <lee@xxxxxxxxxx> wrote:
>
> On Tue, 24 Mar 2026, Alexey Charkov wrote:
>
> > Add register definitions and a new 'type' enum to be passed via MFD
> > private data to support the BQ25792, which is a newer variant of the
> > BQ257xx family.
> >
> > BQ25792 shares similar logic of operation with the already supported
> > BQ25703A but has a completely different register map and different
> > electrical constraints.
> >
> > Tested-by: Chris Morgan <macromorgan@xxxxxxxxxxx>
> > Signed-off-by: Alexey Charkov <alchark@xxxxxxxxxxx>
> > ---
> >  drivers/mfd/bq257xx.c       |  54 +++++-
> >  include/linux/mfd/bq257xx.h | 412 ++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 463 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/mfd/bq257xx.c b/drivers/mfd/bq257xx.c
> > index e9d49dac0a16..31654925afa5 100644
> > --- a/drivers/mfd/bq257xx.c
> > +++ b/drivers/mfd/bq257xx.c
> > @@ -39,6 +39,39 @@ static const struct regmap_config bq25703_regmap_config = {
> >       .val_format_endian = REGMAP_ENDIAN_LITTLE,
> >  };
> >
> > +static const struct regmap_range bq25792_writeable_reg_ranges[] = {
> > +     regmap_reg_range(BQ25792_REG00_MIN_SYS_VOLTAGE,
> > +                      BQ25792_REG18_NTC_CONTROL_1),
> > +     regmap_reg_range(BQ25792_REG28_CHARGER_MASK_0,
> > +                      BQ25792_REG30_ADC_FUNCTION_DISABLE_1),
> > +};
> > +
> > +static const struct regmap_access_table bq25792_writeable_regs = {
> > +     .yes_ranges = bq25792_writeable_reg_ranges,
> > +     .n_yes_ranges = ARRAY_SIZE(bq25792_writeable_reg_ranges),
> > +};
> > +
> > +static const struct regmap_range bq25792_volatile_reg_ranges[] = {
> > +     regmap_reg_range(BQ25792_REG19_ICO_CURRENT_LIMIT,
> > +                      BQ25792_REG27_FAULT_FLAG_1),
> > +     regmap_reg_range(BQ25792_REG31_IBUS_ADC,
> > +                      BQ25792_REG47_DPDM_DRIVER),
> > +};
> > +
> > +static const struct regmap_access_table bq25792_volatile_regs = {
> > +     .yes_ranges = bq25792_volatile_reg_ranges,
> > +     .n_yes_ranges = ARRAY_SIZE(bq25792_volatile_reg_ranges),
> > +};
> > +
> > +static const struct regmap_config bq25792_regmap_config = {
> > +     .reg_bits = 8,
> > +     .val_bits = 8,
> > +     .max_register = BQ25792_REG48_PART_INFORMATION,
> > +     .cache_type = REGCACHE_MAPLE,
> > +     .wr_table = &bq25792_writeable_regs,
> > +     .volatile_table = &bq25792_volatile_regs,
> > +};
> > +
> >  static const struct mfd_cell cells[] = {
> >       MFD_CELL_NAME("bq257xx-regulator"),
> >       MFD_CELL_NAME("bq257xx-charger"),
> > @@ -46,6 +79,7 @@ static const struct mfd_cell cells[] = {
> >
> >  static int bq257xx_probe(struct i2c_client *client)
> >  {
> > +     const struct regmap_config *rcfg;
> >       struct bq257xx_device *ddata;
> >       int ret;
> >
> > @@ -53,9 +87,21 @@ static int bq257xx_probe(struct i2c_client *client)
> >       if (!ddata)
> >               return -ENOMEM;
> >
> > +     ddata->type = (uintptr_t)i2c_get_match_data(client);
> >       ddata->client = client;
> >
> > -     ddata->regmap = devm_regmap_init_i2c(client, &bq25703_regmap_config);
> > +     switch (ddata->type) {
> > +     case BQ25703A:
> > +             rcfg = &bq25703_regmap_config;
> > +             break;
> > +     case BQ25792:
> > +             rcfg = &bq25792_regmap_config;
> > +             break;
> > +     default:
> > +             return dev_err_probe(&client->dev, -EINVAL, "Unsupported device type\n");
>
> Nit: Shouldn't we be returning '-ENODEV' here for an unsupported device?

Hi Lee,

Indeed, I've had a quick look and other drivers seem to return -ENODEV
in similar situations. Shall I respin a new version with that change?

Thanks a lot,
Alexey