Re: [PATCH V2 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

From: Sibi Sankar <sibis@codeaurora.org>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Pradeep P V K <ppvk@codeaurora.org>,
	bjorn.andersson@linaro.org, adrian.hunter@intel.com,
	robh+dt@kernel.org, ulf.hansson@linaro.org,
	vbadigan@codeaurora.org, sboyd@kernel.org,
	georgi.djakov@linaro.org, linux-mmc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	devicetree@vger.kernel.org, linux-mmc-owner@vger.kernel.org,
	rnayak@codeaurora.org, matthias@chromium.org
Subject: Re: [PATCH V2 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support
Date: Fri, 05 Jun 2020 00:04:02 +0530	[thread overview]
Message-ID: <23d6da79d604ce5113d90a2adab17483@codeaurora.org> (raw)
In-Reply-To: <20200604170906.GP4525@google.com>

On 2020-06-04 22:39, Matthias Kaehlcke wrote:
> On Thu, Jun 04, 2020 at 04:44:42PM +0530, Pradeep P V K wrote:
>> Interconnect bandwidth scaling support is now added as a
>> part of OPP [1]. So, make sure interconnect driver is ready
>> before handling interconnect scaling.
>> 
>> This change is based on
>> [1] [Patch v8] Introduce OPP bandwidth bindings
>> (https://lkml.org/lkml/2020/5/12/493)
>> 
>> [2] [Patch v3] mmc: sdhci-msm: Fix error handling
>> for dev_pm_opp_of_add_table()
>> (https://lkml.org/lkml/2020/5/5/491)
>> 
>> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
>> ---
>>  drivers/mmc/host/sdhci-msm.c | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>> 
>> diff --git a/drivers/mmc/host/sdhci-msm.c 
>> b/drivers/mmc/host/sdhci-msm.c
>> index b277dd7..a13ff1b 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -14,6 +14,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/iopoll.h>
>>  #include <linux/regulator/consumer.h>
>> +#include <linux/interconnect.h>
>> 
>>  #include "sdhci-pltfm.h"
>>  #include "cqhci.h"
>> @@ -2070,6 +2071,18 @@ static int sdhci_msm_probe(struct 
>> platform_device *pdev)
>>  	}
>>  	msm_host->bulk_clks[0].clk = clk;
>> 
>> +	/* Make sure that ICC driver is ready for interconnect bandwdith
>> +	 * scaling before registering the device for OPP.
>> +	 */
>> +	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
>> +	if (ret) {
>> +		if (ret == -EPROBE_DEFER)
>> +			dev_info(&pdev->dev, "defer icc path: %d\n", ret);
> 
> I already commented on this on v1:
> 
>   This log seems to add little more than noise, or are there particular 
> reasons
>   why it is useful in this driver? Most drivers just return silently in 
> case of
>   deferred probing.
> 
> If you think the log is really needed please explain why.

Both the err logs seem redundant.
EPROBE_DEFERS are rather readily
noticeable through the return val.
dev_.._find_icc_paths already prints
err messages when we fail to get icc
paths.

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