linux-kernel - Re: [PATCH V1 3/3] mmc: sdhci: Allow platform controlled voltage switching

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Message-ID: <1c4cdb66-25b1-68bf-1474-35b182605fc1@codeaurora.org>
Date:   Wed, 20 May 2020 16:49:05 +0530
From:   Veerabhadrarao Badiganti <vbadigan@...eaurora.org>
To:     Adrian Hunter <adrian.hunter@...el.com>, ulf.hansson@...aro.org,
        robh+dt@...nel.org
Cc:     linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        Vijay Viswanath <vviswana@...eaurora.org>
Subject: Re: [PATCH V1 3/3] mmc: sdhci: Allow platform controlled voltage
 switching


On 5/19/2020 11:36 AM, Adrian Hunter wrote:
> On 15/05/20 2:18 pm, Veerabhadrarao Badiganti wrote:
>> From: Vijay Viswanath <vviswana@...eaurora.org>
>>
>> If vendor platform drivers are controlling whole logic of voltage
>> switching, then sdhci driver no need control vqmmc regulator.
>> So skip enabling/disable vqmmc from SDHC driver.
>>
>> Signed-off-by: Vijay Viswanath <vviswana@...eaurora.org>
>> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@...eaurora.org>
>> ---
>>   drivers/mmc/host/sdhci.c | 32 +++++++++++++++++++-------------
>>   drivers/mmc/host/sdhci.h |  1 +
>>   2 files changed, 20 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 1bb6b67..c010823 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -4098,6 +4098,7 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   	unsigned int override_timeout_clk;
>>   	u32 max_clk;
>>   	int ret;
>> +	bool enable_vqmmc = false;
>>   
>>   	WARN_ON(host == NULL);
>>   	if (host == NULL)
>> @@ -4111,9 +4112,12 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   	 * the host can take the appropriate action if regulators are not
>>   	 * available.
>>   	 */
>> -	ret = mmc_regulator_get_supply(mmc);
>> -	if (ret)
>> -		return ret;
>> +	if (!mmc->supply.vqmmc) {
>> +		ret = mmc_regulator_get_supply(mmc);
>> +		if (ret)
>> +			return ret;
>> +		enable_vqmmc  = true;
>> +	}
>>   
>>   	DBG("Version:   0x%08x | Present:  0x%08x\n",
>>   	    sdhci_readw(host, SDHCI_HOST_VERSION),
>> @@ -4373,7 +4377,15 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   		mmc->caps |= MMC_CAP_NEEDS_POLL;
>>   
>>   	if (!IS_ERR(mmc->supply.vqmmc)) {
>> -		ret = regulator_enable(mmc->supply.vqmmc);
>> +		if (enable_vqmmc) {
>> +			ret = regulator_enable(mmc->supply.vqmmc);
>> +			if (ret) {
>> +				pr_warn("%s: Failed to enable vqmmc regulator: %d\n",
>> +					mmc_hostname(mmc), ret);
>> +				mmc->supply.vqmmc = ERR_PTR(-EINVAL);
>> +			}
>> +			host->vqmmc_enabled = !ret;
>> +		}
>>   
>>   		/* If vqmmc provides no 1.8V signalling, then there's no UHS */
>>   		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>> @@ -4386,12 +4398,6 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 2700000,
>>   						    3600000))
>>   			host->flags &= ~SDHCI_SIGNALING_330;
>> -
>> -		if (ret) {
>> -			pr_warn("%s: Failed to enable vqmmc regulator: %d\n",
>> -				mmc_hostname(mmc), ret);
>> -			mmc->supply.vqmmc = ERR_PTR(-EINVAL);
>> -		}
>>   	}
>>   
>>   	if (host->quirks2 & SDHCI_QUIRK2_NO_1_8_V) {
>> @@ -4625,7 +4631,7 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   	return 0;
>>   
>>   unreg:
>> -	if (!IS_ERR(mmc->supply.vqmmc))
>> +	if (host->vqmmc_enabled)
>>   		regulator_disable(mmc->supply.vqmmc);
>>   undma:
>>   	if (host->align_buffer)
>> @@ -4643,7 +4649,7 @@ void sdhci_cleanup_host(struct sdhci_host *host)
>>   {
>>   	struct mmc_host *mmc = host->mmc;
>>   
>> -	if (!IS_ERR(mmc->supply.vqmmc))
>> +	if (host->vqmmc_enabled)
>>   		regulator_disable(mmc->supply.vqmmc);
>>   
>>   	if (host->align_buffer)
>> @@ -4780,7 +4786,7 @@ void sdhci_remove_host(struct sdhci_host *host, int dead)
>>   
>>   	destroy_workqueue(host->complete_wq);
>>   
>> -	if (!IS_ERR(mmc->supply.vqmmc))
>> +	if (host->vqmmc_enabled)
>>   		regulator_disable(mmc->supply.vqmmc);
>>   
>>   	if (host->align_buffer)
>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>> index 8d2a096..24d27e1 100644
>> --- a/drivers/mmc/host/sdhci.h
>> +++ b/drivers/mmc/host/sdhci.h
>> @@ -570,6 +570,7 @@ struct sdhci_host {
>>   	u32 caps1;		/* CAPABILITY_1 */
>>   	bool read_caps;		/* Capability flags have been read */
>>   
>> +	bool vqmmc_enabled;	/* Vqmmc is enabled */
> Last time around there was dissatisfaction with this variable name.  Perhaps
> change it to sdhci_core_to_disable_vqmmc

Sure Adrian. Will update this variable name.

>
>>   	unsigned int            ocr_avail_sdio;	/* OCR bit masks */
>>   	unsigned int            ocr_avail_sd;
>>   	unsigned int            ocr_avail_mmc;
>>