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References: <20230609083009.2822259-1-wenst@chromium.org> <20230609083009.2822259-4-wenst@chromium.org>
In-Reply-To: <20230609083009.2822259-4-wenst@chromium.org>
From:   Fei Shao <fshao@chromium.org>
Date:   Mon, 12 Jun 2023 18:56:57 +0800
Message-ID: <CAJ66y9H91WaRxaZzXRYc5LN9t+M+ZpEy6nbgo=W1kOn_Yu_BCg@mail.gmail.com>
Subject: Re: [PATCH 3/9] regulator: mt6358: Merge VCN33_* regulators
To:     Chen-Yu Tsai <wenst@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
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On Fri, Jun 9, 2023 at 4:30=E2=80=AFPM Chen-Yu Tsai <wenst@chromium.org> wr=
ote:
>
> 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 driver
> 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/mt6=
358-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_regulator=
s[] =3D {
>                    MT6358_LDO_VCAMA1_CON0, 0, MT6358_VCAMA1_ANA_CON0, 0xf=
00),
>         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, 0x3=
00),
>         MT6358_LDO("ldo_vcama2", VCAMA2, vcama_voltages, vcama_idx,
>                    MT6358_LDO_VCAMA2_CON0, 0, MT6358_VCAMA2_ANA_CON0, 0xf=
00),
>         MT6358_LDO("ldo_vmc", VMC, vmc_voltages, vmc_idx,
> @@ -662,12 +658,8 @@ static struct mt6358_regulator_info mt6366_regulator=
s[] =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, 0x3=
00),
>         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_regulato=
rs[] =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 s=
ame
> +        * regulator. They share the same voltage setting and output pin.
> +        * Instead of having two potentially conflicting regulators, just=
 have
> +        * one VCN33 regulator. Sync the two enable bits and only use one=
 in
> +        * the regulator device.
> +        */
> +       ret =3D regmap_read(mt6397->regmap, MT6358_LDO_VCN33_CON0_1, &val=
);
> +       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_CON0_=
0, BIT(0), BIT(0));
> +       if (ret) {
> +               dev_err(dev, "Failed to sync VCN33_WIFI setting to VCN33_=
BT\n");
> +               return ret;
> +       }
> +
> +       /* Disable VCN33_WIFI */
> +       ret =3D regmap_update_bits(mt6397->regmap, MT6358_LDO_VCN33_CON0_=
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?

Regards,
Fei