linux-kernel - Re: [RESEND PATCH v6 3/3] input: pm8xxx-vibrator: add new SPMI vibrator support

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Date:   Mon, 9 Oct 2023 12:01:03 +0800
From:   Fenglin Wu <quic_fenglinw@...cinc.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <robh+dt@...nel.org>,
        <agross@...nel.org>, <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        <linux-input@...r.kernel.org>, <quic_collinsd@...cinc.com>,
        <quic_subbaram@...cinc.com>, <quic_kamalw@...cinc.com>,
        <jestar@....qualcomm.com>, Luca Weiss <luca.weiss@...rphone.com>
Subject: Re: [RESEND PATCH v6 3/3] input: pm8xxx-vibrator: add new SPMI
 vibrator support

On 10/1/2023 12:17 AM, Dmitry Torokhov wrote:
> On Mon, Sep 25, 2023 at 10:54:45AM +0800, Fenglin Wu wrote:
>>
>>
>> On 9/24/2023 3:07 AM, Dmitry Baryshkov wrote:
>>>> +
>>>> +       switch (vib->data->hw_type) {
>>>> +       case SSBI_VIB:
>>>>                   mask = SSBI_VIB_DRV_LEVEL_MASK;
>>>>                   shift = SSBI_VIB_DRV_SHIFT;
>>>> +               break;
>>>> +       case SPMI_VIB:
>>>> +               mask = SPMI_VIB_DRV_LEVEL_MASK;
>>>> +               shift = SPMI_VIB_DRV_SHIFT;
>>>> +               break;
>>>> +       case SPMI_VIB_GEN2:
>>>> +               mask = SPMI_VIB_GEN2_DRV_MASK;
>>>> +               shift = SPMI_VIB_GEN2_DRV_SHIFT;
>>>> +               break;
>>>> +       default:
>>>> +               return -EINVAL;
>>> Could you please move the switch to the previous patch? Then it would
>>> be more obvious that you are just adding the SPMI_VIB_GEN2 here.
>>>
>>> Other than that LGTM.
>>
>> Sure, I can move the switch to the previous refactoring patch.
> 
> Actually, the idea of having a const "reg" or "chip", etc. structure is
> to avoid this kind of runtime checks based on hardware type and instead
> use common computation. I believe you need to move mask and shift into
> the chip-specific structure and avoid defining hw_type.
> 

Actually, the main motivation for adding 'hw_type' is to avoid reading 
'reg_base' from DT for SSBI_VIB. It can also help to simplify the 
'pm8xxx_vib_data' structure and make following code logic more 
straightforward and easier to understand(check hw_type instead of 
checking specific constant reg/mask value), it has been used in 
following places:

   1) Avoid reading 'reg_base' from DT for SSBI_VIB.
   2) Only do manual-mode-mask-write for SSBI_VIB. Previously, it was 
achieved by giving a valid 'drv_en_manual_mask' value only for SSBI_VIB, 
having hw_type make it more straightforward.
   3) Not writing VIB_EN register for SSBI_VIB. A similar strategy was 
used previously, only write VIB_EN register when 'enable_mask' is valid, 
  checking hw_type make it more straightforward.
   4) To achieve different drive step size for SPMI_VIB （100mV per step) 
and SPMI_VIB_GEN2 (1mV per step).
   5) Do different VIB_DRV mask and shift assignment for SPMI_VIB and 
SPMI_VIB_GEN2
   6) Only write VIB_DRV2 for SPMI_VIB_GEN2.

> Thanks.
>