diff mbox series

[v2,3/3] mmc: sdhci-msm: drop redundant of_device_id entries

Message ID 20220712150219.20539-4-krzysztof.kozlowski@linaro.org
State Superseded
Headers show
Series dt-bindings: mmc: / ARM: qcom: add MSM8998 and cleanup driver of_device_id | expand

Commit Message

Krzysztof Kozlowski July 12, 2022, 3:02 p.m. UTC
This reverts three commits:
1. Revert "mmc: sdhci-msm: Add compatible string check for sdx65"
   This reverts commit 953706844f0f2fd4dc6984cc010fe6cf51c041f2.

2. Revert "mmc: sdhci-msm: Add compatible string check for sm8150"
   This reverts commit 5acd6adb65802cc6f9986be3750179a820580d37.

3. Revert "mmc: sdhci-msm: Add SoC specific compatibles"
   This reverts commit 466614a9765c6fb67e1464d0a3f1261db903834b.

The oldest commit 466614a9765c ("mmc: sdhci-msm: Add SoC specific
compatibles") did not specify what benefits such multiple compatibles
bring, therefore assume there is none.  On the other hand such approach
brings a lot of churn to driver maintenance by expecting commit for
every new compatible, even though it is already covered by the fallback.

There is really no sense in duplicating of_device_id for each
variant, which is already covered by generic compatible fallback
qcom,sdhci-msm-v4 or qcom,sdhci-msm-v5.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

Cc: Konrad Dybcio <konrad.dybcio@somainline.org>
Cc: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Cc: Doug Anderson <dianders@chromium.org>
---
 drivers/mmc/host/sdhci-msm.c | 25 -------------------------
 1 file changed, 25 deletions(-)

Comments

Doug Anderson July 13, 2022, 3:57 p.m. UTC | #1
Hi,

On Tue, Jul 12, 2022 at 8:02 AM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> This reverts three commits:
> 1. Revert "mmc: sdhci-msm: Add compatible string check for sdx65"
>    This reverts commit 953706844f0f2fd4dc6984cc010fe6cf51c041f2.
>
> 2. Revert "mmc: sdhci-msm: Add compatible string check for sm8150"
>    This reverts commit 5acd6adb65802cc6f9986be3750179a820580d37.
>
> 3. Revert "mmc: sdhci-msm: Add SoC specific compatibles"
>    This reverts commit 466614a9765c6fb67e1464d0a3f1261db903834b.
>
> The oldest commit 466614a9765c ("mmc: sdhci-msm: Add SoC specific
> compatibles") did not specify what benefits such multiple compatibles
> bring, therefore assume there is none.  On the other hand such approach
> brings a lot of churn to driver maintenance by expecting commit for
> every new compatible, even though it is already covered by the fallback.
>
> There is really no sense in duplicating of_device_id for each
> variant, which is already covered by generic compatible fallback
> qcom,sdhci-msm-v4 or qcom,sdhci-msm-v5.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Personally, I would have taken the extra step and added a comment in
the code to prevent someone from doing this again. Maybe like this:

/*
 * In the device tree, all boards are required to have _two_ compatible
 * strings listed: a SoC-specific one followed by a more generic one.
 * Normally we can just rely on the generic string, but we always
 * include both so that if we ever find a bug on a specific SoC that
 * we need to workaround (like in sdm845/sc7180) that we can quickly
 * work around it without any changes to the dts.
 */

In any case:

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Krzysztof Kozlowski July 13, 2022, 4:07 p.m. UTC | #2
On 13/07/2022 17:57, Doug Anderson wrote:
> Hi,
> 
> On Tue, Jul 12, 2022 at 8:02 AM Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> This reverts three commits:
>> 1. Revert "mmc: sdhci-msm: Add compatible string check for sdx65"
>>    This reverts commit 953706844f0f2fd4dc6984cc010fe6cf51c041f2.
>>
>> 2. Revert "mmc: sdhci-msm: Add compatible string check for sm8150"
>>    This reverts commit 5acd6adb65802cc6f9986be3750179a820580d37.
>>
>> 3. Revert "mmc: sdhci-msm: Add SoC specific compatibles"
>>    This reverts commit 466614a9765c6fb67e1464d0a3f1261db903834b.
>>
>> The oldest commit 466614a9765c ("mmc: sdhci-msm: Add SoC specific
>> compatibles") did not specify what benefits such multiple compatibles
>> bring, therefore assume there is none.  On the other hand such approach
>> brings a lot of churn to driver maintenance by expecting commit for
>> every new compatible, even though it is already covered by the fallback.
>>
>> There is really no sense in duplicating of_device_id for each
>> variant, which is already covered by generic compatible fallback
>> qcom,sdhci-msm-v4 or qcom,sdhci-msm-v5.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> 
> Personally, I would have taken the extra step and added a comment in
> the code to prevent someone from doing this again. Maybe like this:
> 
> /*
>  * In the device tree, all boards are required to have _two_ compatible
>  * strings listed: a SoC-specific one followed by a more generic one.
>  * Normally we can just rely on the generic string, but we always
>  * include both so that if we ever find a bug on a specific SoC that
>  * we need to workaround (like in sdm845/sc7180) that we can quickly
>  * work around it without any changes to the dts.
>  */

This actually does not instruct the developer not to add new variants to
the driver, so how about something like:

/* Do not add new variants to the driver which are compatible with
generic ones, unless they need customization. */
?

The problem is that this applies to several such drivers on several
platforms (Qualcomm, NXP - these for sure use such pattern), so we would
be documenting something obvious, IMO.

> 
> In any case:
> 
> Reviewed-by: Douglas Anderson <dianders@chromium.org>


Best regards,
Krzysztof
Doug Anderson July 13, 2022, 4:10 p.m. UTC | #3
Hi,

On Wed, Jul 13, 2022 at 9:07 AM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> On 13/07/2022 17:57, Doug Anderson wrote:
> > Hi,
> >
> > On Tue, Jul 12, 2022 at 8:02 AM Krzysztof Kozlowski
> > <krzysztof.kozlowski@linaro.org> wrote:
> >>
> >> This reverts three commits:
> >> 1. Revert "mmc: sdhci-msm: Add compatible string check for sdx65"
> >>    This reverts commit 953706844f0f2fd4dc6984cc010fe6cf51c041f2.
> >>
> >> 2. Revert "mmc: sdhci-msm: Add compatible string check for sm8150"
> >>    This reverts commit 5acd6adb65802cc6f9986be3750179a820580d37.
> >>
> >> 3. Revert "mmc: sdhci-msm: Add SoC specific compatibles"
> >>    This reverts commit 466614a9765c6fb67e1464d0a3f1261db903834b.
> >>
> >> The oldest commit 466614a9765c ("mmc: sdhci-msm: Add SoC specific
> >> compatibles") did not specify what benefits such multiple compatibles
> >> bring, therefore assume there is none.  On the other hand such approach
> >> brings a lot of churn to driver maintenance by expecting commit for
> >> every new compatible, even though it is already covered by the fallback.
> >>
> >> There is really no sense in duplicating of_device_id for each
> >> variant, which is already covered by generic compatible fallback
> >> qcom,sdhci-msm-v4 or qcom,sdhci-msm-v5.
> >>
> >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> >
> > Personally, I would have taken the extra step and added a comment in
> > the code to prevent someone from doing this again. Maybe like this:
> >
> > /*
> >  * In the device tree, all boards are required to have _two_ compatible
> >  * strings listed: a SoC-specific one followed by a more generic one.
> >  * Normally we can just rely on the generic string, but we always
> >  * include both so that if we ever find a bug on a specific SoC that
> >  * we need to workaround (like in sdm845/sc7180) that we can quickly
> >  * work around it without any changes to the dts.
> >  */
>
> This actually does not instruct the developer not to add new variants to
> the driver, so how about something like:
>
> /* Do not add new variants to the driver which are compatible with
> generic ones, unless they need customization. */
> ?

Sure, that would be fine.


> The problem is that this applies to several such drivers on several
> platforms (Qualcomm, NXP - these for sure use such pattern), so we would
> be documenting something obvious, IMO.

The problem is that the people adding to this file are probably not
device tree experts and may not know, so a short comment might be
worthwhile. If you don't think it's a good idea, though, I won't push.

-Doug
diff mbox series

Patch

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index e395411fb6fd..ff9f5b63c337 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -2435,33 +2435,8 @@  static const struct sdhci_msm_variant_info sdm845_sdhci_var = {
 };
 
 static const struct of_device_id sdhci_msm_dt_match[] = {
-	 /* Following two entries are deprecated (kept only for backward compatibility) */
 	{.compatible = "qcom,sdhci-msm-v4", .data = &sdhci_msm_mci_var},
 	{.compatible = "qcom,sdhci-msm-v5", .data = &sdhci_msm_v5_var},
-	/* Add entries for sdcc versions less than 5.0 here */
-	{.compatible = "qcom,apq8084-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8226-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8916-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8953-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8974-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8992-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8994-sdhci", .data = &sdhci_msm_mci_var},
-	{.compatible = "qcom,msm8996-sdhci", .data = &sdhci_msm_mci_var},
-	/*
-	 * Add entries for sdcc version 5.0 here. For SDCC version 5.0.0,
-	 * MCI registers are removed from SDCC interface and some registers
-	 * are moved to HC.
-	 */
-	{.compatible = "qcom,qcs404-sdhci", .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sdx55-sdhci",  .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sdx65-sdhci",  .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sdm630-sdhci", .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sm6125-sdhci", .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sm6350-sdhci", .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sm8150-sdhci", .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sm8250-sdhci", .data = &sdhci_msm_v5_var},
-	{.compatible = "qcom,sc7280-sdhci", .data = &sdhci_msm_v5_var},
-	/* Add entries where soc specific handling is required, here */
 	{.compatible = "qcom,sdm845-sdhci", .data = &sdm845_sdhci_var},
 	{.compatible = "qcom,sc7180-sdhci", .data = &sdm845_sdhci_var},
 	{},