Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230609083009.2822259-1-wenst@chromium.org> <20230609083009.2822259-4-wenst@chromium.org>
 <CAJ66y9H91WaRxaZzXRYc5LN9t+M+ZpEy6nbgo=W1kOn_Yu_BCg@mail.gmail.com>
In-Reply-To: <CAJ66y9H91WaRxaZzXRYc5LN9t+M+ZpEy6nbgo=W1kOn_Yu_BCg@mail.gmail.com>
From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Thu, 15 Jun 2023 15:37:34 +0800
Message-ID: <CAGXv+5FOy+d_j=8uKHwUqih_po=Pt590BkBGMFc+Td9rBhutRA@mail.gmail.com>
Subject: Re: [PATCH 3/9] regulator: mt6358: Merge VCN33_* regulators
To:     Fei Shao <fshao@chromium.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Mark Brown <broonie@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, Jun 12, 2023 at 6:57=E2=80=AFPM Fei Shao <fshao@chromium.org> wrote=
:
>
> On Fri, Jun 9, 2023 at 4:30=E2=80=AFPM Chen-Yu Tsai <wenst@chromium.org> =
wrote:
> >
> > The VCN33_BT and VCN33_WIFI regulators are actually the same regulator,
> > having the same voltage setting and output pin. There are simply two
> > enable bits that are ORed together to enable the regulator.
> >
> > Having two regulators representing the same output pin is misleading
> > from a design matching standpoint, and also error-prone in driver
> > implementations. If consumers try to set different voltages on either
> > regulator, the one set later would override the one set before. There
> > are ways around this, such as chaining them together and having the
> > downstream one act as a switch. But given there's only one output pin,
> > such a workaround doesn't match reality.
> >
> > Remove the VCN33_WIFI regulator. During the probe phase, have the drive=
r
> > sync the enable status of VCN33_WIFI to VCN33_BT. Also drop the suffix
> > so that the regulator name matches the pin name in the datasheet.
> >
> > Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> > ---
> >  drivers/regulator/mt6358-regulator.c       | 65 +++++++++++++++++-----
> >  include/linux/regulator/mt6358-regulator.h |  6 +-
> >  2 files changed, 52 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/regulator/mt6358-regulator.c b/drivers/regulator/m=
t6358-regulator.c
> > index c9e16bd092f6..faf6b0757019 100644
> > --- a/drivers/regulator/mt6358-regulator.c
> > +++ b/drivers/regulator/mt6358-regulator.c
> > @@ -277,7 +277,7 @@ static const unsigned int vcama_voltages[] =3D {
> >         2800000, 2900000, 3000000,
> >  };
> >
> > -static const unsigned int vcn33_bt_wifi_voltages[] =3D {
> > +static const unsigned int vcn33_voltages[] =3D {
> >         3300000, 3400000, 3500000,
> >  };
> >
> > @@ -321,7 +321,7 @@ static const u32 vcama_idx[] =3D {
> >         0, 7, 9, 10, 11, 12,
> >  };
> >
> > -static const u32 vcn33_bt_wifi_idx[] =3D {
> > +static const u32 vcn33_idx[] =3D {
> >         1, 2, 3,
> >  };
> >
> > @@ -566,12 +566,8 @@ static struct mt6358_regulator_info mt6358_regulat=
ors[] =3D {
> >                    MT6358_LDO_VCAMA1_CON0, 0, MT6358_VCAMA1_ANA_CON0, 0=
xf00),
> >         MT6358_LDO("ldo_vemc", VEMC, vmch_vemc_voltages, vmch_vemc_idx,
> >                    MT6358_LDO_VEMC_CON0, 0, MT6358_VEMC_ANA_CON0, 0x700=
),
> > -       MT6358_LDO("ldo_vcn33_bt", VCN33_BT, vcn33_bt_wifi_voltages,
> > -                  vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_0,
> > -                  0, MT6358_VCN33_ANA_CON0, 0x300),
> > -       MT6358_LDO("ldo_vcn33_wifi", VCN33_WIFI, vcn33_bt_wifi_voltages=
,
> > -                  vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_1,
> > -                  0, MT6358_VCN33_ANA_CON0, 0x300),
> > +       MT6358_LDO("ldo_vcn33", VCN33, vcn33_voltages, vcn33_idx,
> > +                  MT6358_LDO_VCN33_CON0_0, 0, MT6358_VCN33_ANA_CON0, 0=
x300),
> >         MT6358_LDO("ldo_vcama2", VCAMA2, vcama_voltages, vcama_idx,
> >                    MT6358_LDO_VCAMA2_CON0, 0, MT6358_VCAMA2_ANA_CON0, 0=
xf00),
> >         MT6358_LDO("ldo_vmc", VMC, vmc_voltages, vmc_idx,
> > @@ -662,12 +658,8 @@ static struct mt6358_regulator_info mt6366_regulat=
ors[] =3D {
> >                    MT6358_LDO_VMCH_CON0, 0, MT6358_VMCH_ANA_CON0, 0x700=
),
> >         MT6366_LDO("ldo_vemc", VEMC, vmch_vemc_voltages, vmch_vemc_idx,
> >                    MT6358_LDO_VEMC_CON0, 0, MT6358_VEMC_ANA_CON0, 0x700=
),
> > -       MT6366_LDO("ldo_vcn33_bt", VCN33_BT, vcn33_bt_wifi_voltages,
> > -                  vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_0,
> > -                  0, MT6358_VCN33_ANA_CON0, 0x300),
> > -       MT6366_LDO("ldo_vcn33_wifi", VCN33_WIFI, vcn33_bt_wifi_voltages=
,
> > -                  vcn33_bt_wifi_idx, MT6358_LDO_VCN33_CON0_1,
> > -                  0, MT6358_VCN33_ANA_CON0, 0x300),
> > +       MT6366_LDO("ldo_vcn33", VCN33, vcn33_voltages, vcn33_idx,
> > +                  MT6358_LDO_VCN33_CON0_0, 0, MT6358_VCN33_ANA_CON0, 0=
x300),
> >         MT6366_LDO("ldo_vmc", VMC, vmc_voltages, vmc_idx,
> >                    MT6358_LDO_VMC_CON0, 0, MT6358_VMC_ANA_CON0, 0xf00),
> >         MT6366_LDO("ldo_vsim2", VSIM2, vsim_voltages, vsim_idx,
> > @@ -690,13 +682,56 @@ static struct mt6358_regulator_info mt6366_regula=
tors[] =3D {
> >                     MT6358_LDO_VSRAM_CON1, 0x7f),
> >  };
> >
> > +static int mt6358_sync_vcn33_setting(struct device *dev)
> > +{
> > +       struct mt6397_chip *mt6397 =3D dev_get_drvdata(dev->parent);
> > +       unsigned int val;
> > +       int ret;
> > +
> > +       /*
> > +        * VCN33_WIFI and VCN33_BT are two separate enable bits for the=
 same
> > +        * regulator. They share the same voltage setting and output pi=
n.
> > +        * Instead of having two potentially conflicting regulators, ju=
st have
> > +        * one VCN33 regulator. Sync the two enable bits and only use o=
ne in
> > +        * the regulator device.
> > +        */
> > +       ret =3D regmap_read(mt6397->regmap, MT6358_LDO_VCN33_CON0_1, &v=
al);
> > +       if (ret) {
> > +               dev_err(dev, "Failed to read VCN33_WIFI setting\n");
> > +               return ret;
> > +       }
> > +
> > +       if (!(val & BIT(0)))
> > +               return 0;
> > +
> > +       /* Sync VCN33_WIFI enable status to VCN33_BT */
> > +       ret =3D regmap_update_bits(mt6397->regmap, MT6358_LDO_VCN33_CON=
0_0, BIT(0), BIT(0));
> > +       if (ret) {
> > +               dev_err(dev, "Failed to sync VCN33_WIFI setting to VCN3=
3_BT\n");
> > +               return ret;
> > +       }
> > +
> > +       /* Disable VCN33_WIFI */
> > +       ret =3D regmap_update_bits(mt6397->regmap, MT6358_LDO_VCN33_CON=
0_1, BIT(0), 0);
> > +       if (ret) {
> > +               dev_err(dev, "Failed to disable VCN33_BT\n");
>
> I think it should be "VCN33_WIFI" in the error message?

Mark already merged the patch. I send followup fixes for this and the
call sequence.

ChenYu