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In-Reply-To: <501bc7d0-1f97-1c53-a7f8-701ab9dfdf8e@quicinc.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Tue, 18 Jul 2023 14:04:09 +0300
Message-ID: <CAA8EJppjshTCqeYQL1QUbLd03bopZjGHuOhoFqy7P8XuzYXc9w@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] Input: pm8xxx-vib - Add support for more PMICs
To:     Fenglin Wu <quic_fenglinw@quicinc.com>
Cc:     linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        linux-input@vger.kernel.org, quic_collinsd@quicinc.com,
        quic_subbaram@quicinc.com, quic_kamalw@quicinc.com,
        jestar@qti.qualcomm.com, quic_huliu@quicinc.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, 18 Jul 2023 at 13:55, Fenglin Wu <quic_fenglinw@quicinc.com> wrote:
>
>
>
> On 7/18/2023 5:41 PM, Dmitry Baryshkov wrote:
> > On Tue, 18 Jul 2023 at 09:58, Fenglin Wu <quic_fenglinw@quicinc.com> wrote:
> >>
> >>
> >>
> >> On 7/18/2023 2:44 PM, Dmitry Baryshkov wrote:
> >>> On Tue, 18 Jul 2023 at 09:27, Fenglin Wu <quic_fenglinw@quicinc.com> wrote:
> >>>>
> >>>> Add support for vibrator module inside PMI632, PM7250B, PM7325B.
> >>>> It is very similar to vibrator inside PM8xxx but just the drive
> >>>> amplitude is controlled through 2 bytes registers.
> >>>>
> >>>> Signed-off-by: Fenglin Wu <quic_fenglinw@quicinc.com>
> >>>> ---
> >>>>    drivers/input/misc/pm8xxx-vibrator.c | 48 ++++++++++++++++++++++++++++
> >>>>    1 file changed, 48 insertions(+)
> >>>>
> >>>> diff --git a/drivers/input/misc/pm8xxx-vibrator.c b/drivers/input/misc/pm8xxx-vibrator.c
> >>>> index 04cb87efd799..213fdfd47c7f 100644
> >>>> --- a/drivers/input/misc/pm8xxx-vibrator.c
> >>>> +++ b/drivers/input/misc/pm8xxx-vibrator.c
> >>>> @@ -25,6 +25,9 @@ struct pm8xxx_regs {
> >>>>           unsigned int drv_addr;
> >>>>           unsigned int drv_mask;
> >>>>           unsigned int drv_shift;
> >>>> +       unsigned int drv_addr2;
> >>>> +       unsigned int drv_mask2;
> >>>> +       unsigned int drv_shift2;
> >>>>           unsigned int drv_en_manual_mask;
> >>>>    };
> >>>>
> >>>> @@ -44,6 +47,42 @@ static struct pm8xxx_regs pm8916_regs = {
> >>>>           .drv_en_manual_mask = 0,
> >>>>    };
> >>>>
> >>>> +static struct pm8xxx_regs pmi632_regs = {
> >>>> +       .enable_addr = 0x5746,
> >>>> +       .enable_mask = BIT(7),
> >>>> +       .drv_addr = 0x5740,
> >>>> +       .drv_mask = 0xff,
> >>>> +       .drv_shift = 0,
> >>>> +       .drv_addr2 = 0x5741,
> >>>> +       .drv_mask2 = 0x0f,
> >>>> +       .drv_shift2 = 8,
> >>>
> >>> I see that you are just expanding what was done for SSBI PMICs and
> >>> later expanded to support pm8916. However it might be better to drop
> >>> the hardcoded .drv_addr (and drv_addr2) and read address from DT
> >>> instead.
> >>>
> >>
> >> Right, this is the simplest change without updating the code logic too
> >> much. If we decided to read .drv_addr and .drv_add2 from DT, we will
> >> have to read .enable_addr along with all other mask/shift for each
> >> register address from DT as well because they are not consistent from
> >> target to target. I don't know how would you suggest to add the DT
> >> properties for all of them, but if we end up to add a property for each
> >> of them, it won't be cleaner than hard-coding them.
> >
> > No, we (correctly) have device compatibles for that. The issue with
> > hardcoding register addresses is that it adds extra issues here.
> >
> > If I understand correctly, we have several 'generation':
> > - SSBI PMIC, shifted 5-bit mask, en_manual_mask, no enable_register.
> > - older SPMI PMIC, 5 bit drv_mask, 0 en_manual_mask, enable register at +6
> > - new SPMI PMIC, 12 bit drv_mask, 0 en_manual_mask, enable register at +6
> >
> > For the last generation you are adding three independent entries,
> > while the block looks the same. If you remove drv_addr (and get it
> > from reg property), it would allow us to keep only the functional data
> > in struct pm8xxxx_regs (masks / shifts).
> >
>
> Okay, let me know if I understood it correctly, this is what you are
> suggesting:
>
>    - hard code the mask/shifts and still keep them in struct pm8xxx_regs,
>      combine the drv_mask2 to the upper byte of the drv_mask, so we will
>      have following data structure for the 3rd generation vibrator
>
>      static struct pm8xxx_regs pm7250b_regs = {
>          .enable_addr = 0x5346,
>          .enable_mask = BIT(7),
>          .drv_mask = 0xfff,
>          .drv_shift = 0,
>          .drv_en_manual_mask = 0,
>      };
>
>
>    - move the drv_addr/drv_addr2 into DT, read them from 'reg' property.
>      Because of 'mfd/qcom,spmi-pmic.yaml' has defined the 'address-cells'
>      as 1 and the 'size-cells' as 0 for qcom spmi devices, we couldn't
>      specify the address size to 2 even the drv_addr for the 3rd
>      generation vibrator is 2 adjacent bytes. So we will end of having
>      following DT scheme:
>
>        For the 2nd generation which only has drv_addr
>         vibrator@c041 {
>               compatible = "qcom,pm8916-vib";
>               reg = <0xc041>;  /* drv_addr */

No. This is <0xc000>.

>               ...
>         };
>
>        For the 3rd generation which has both drv_addr and drv_addr2
>          vibrator@5340 {
>               compatible = "qcom,pm7250b-vib";
>              reg = <0x5340>,  /* drv_addr */
>                    <0x5341>;  /* drv_addr2 */
>              ...
>         };
>
> Not sure how do you feel, I actually don't see too much benefit than
> hard-coding them in the driver.
> We will end up having code to check how many u32 value in the 'reg' and
> only assign it to drv_addr2 when the 2nd is available, also when
> programming drv_addr2 register, the driver will always assume the mask
> is in the upper byte of the drv_mask and the shift to the drive level is
> 8 (this seems hacky to me and it was my biggest concern while I made
> this change, and it led me to defining drv_shift2/drv_mask2 along with
> drv_addr2).

We only need drv_addr2 if drv_mask has more than 8 bits. So you don't
have to specify it in the DT. It is always equal to base_reg + 0x41.
The same way drv_addr is always equal to base_reg + 0x40 for all
SPMI-based PMIC vibrator devices.

>
>
>
> >>
> >>
> >>>> +       .drv_en_manual_mask = 0,
> >>>> +};
> >>>> +
> >>>> +static struct pm8xxx_regs pm7250b_regs = {
> >>>> +       .enable_addr = 0x5346,
> >>>> +       .enable_mask = BIT(7),
> >>>> +       .drv_addr = 0x5340,
> >>>> +       .drv_mask = 0xff,
> >>>> +       .drv_shift = 0,
> >>>> +       .drv_addr2 = 0x5341,
> >>>> +       .drv_mask2 = 0x0f,
> >>>> +       .drv_shift2 = 8,
> >>>> +       .drv_en_manual_mask = 0,
> >>>> +};
> >>>> +
> >>>> +static struct pm8xxx_regs pm7325b_regs = {
> >>>> +       .enable_addr = 0xdf46,
> >>>> +       .enable_mask = BIT(7),
> >>>> +       .drv_addr = 0xdf40,
> >>>> +       .drv_mask = 0xff,
> >>>> +       .drv_shift = 0,
> >>>> +       .drv_addr2 = 0xdf41,
> >>>> +       .drv_mask2 = 0x0f,
> >>>> +       .drv_shift2 = 8,
> >>>> +       .drv_en_manual_mask = 0,
> >>>> +};
> >>>> +
> >>>>    /**
> >>>>     * struct pm8xxx_vib - structure to hold vibrator data
> >>>>     * @vib_input_dev: input device supporting force feedback
> >>>> @@ -87,6 +126,12 @@ static int pm8xxx_vib_set(struct pm8xxx_vib *vib, bool on)
> >>>>                   return rc;
> >>>>
> >>>>           vib->reg_vib_drv = val;
> >>>> +       if (regs->drv_addr2 != 0 && on) {
> >>>> +               val = (vib->level << regs->drv_shift2) & regs->drv_mask2;
> >>>> +               rc = regmap_write(vib->regmap, regs->drv_addr2, val);
> >>>> +               if (rc < 0)
> >>>> +                       return rc;
> >>>> +       }
> >>>>
> >>>>           if (regs->enable_mask)
> >>>>                   rc = regmap_update_bits(vib->regmap, regs->enable_addr,
> >>>> @@ -242,6 +287,9 @@ static const struct of_device_id pm8xxx_vib_id_table[] = {
> >>>>           { .compatible = "qcom,pm8058-vib", .data = &pm8058_regs },
> >>>>           { .compatible = "qcom,pm8921-vib", .data = &pm8058_regs },
> >>>>           { .compatible = "qcom,pm8916-vib", .data = &pm8916_regs },
> >>>> +       { .compatible = "qcom,pmi632-vib", .data = &pmi632_regs },
> >>>> +       { .compatible = "qcom,pm7250b-vib", .data = &pm7250b_regs },
> >>>> +       { .compatible = "qcom,pm7325b-vib", .data = &pm7325b_regs },
> >>>>           { }
> >>>>    };
> >>>>    MODULE_DEVICE_TABLE(of, pm8xxx_vib_id_table);
> >>>> --
> >>>> 2.25.1
> >>>>
> >>>
> >>>
> >
> >
> >


-- 
With best wishes
Dmitry