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

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Date:   Tue, 19 May 2020 09:06:43 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Veerabhadrarao Badiganti <vbadigan@...eaurora.org>,
        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 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

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