linux-kernel - Re: [PATCH 3/3] mmc: sdhci-sprd: Add pin control support for voltage switch

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Message-ID: <bc6ae189-ca6b-5447-907e-41ec05b2926c@intel.com>
Date:   Mon, 1 Jul 2019 16:31:25 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Baolin Wang <baolin.wang@...aro.org>, ulf.hansson@...aro.org,
        zhang.lyra@...il.com, orsonzhai@...il.com, robh+dt@...nel.org,
        mark.rutland@....com
Cc:     vincent.guittot@...aro.org, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH 3/3] mmc: sdhci-sprd: Add pin control support for voltage
 switch

On 21/06/19 9:12 AM, Baolin Wang wrote:
> For Spreadtrum SD card voltage switching, besides regulator setting,
> it also need switch related pin's state to output corresponding voltage.
> 
> This patch adds pin control operation to support voltage switch.
> 
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> ---
>  drivers/mmc/host/sdhci-sprd.c |   54 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
> index 8b23c88..6ee340a 100644
> --- a/drivers/mmc/host/sdhci-sprd.c
> +++ b/drivers/mmc/host/sdhci-sprd.c
> @@ -12,6 +12,7 @@
>  #include <linux/of.h>
>  #include <linux/of_device.h>
>  #include <linux/of_gpio.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
> @@ -72,6 +73,9 @@ struct sdhci_sprd_host {
>  	struct clk *clk_sdio;
>  	struct clk *clk_enable;
>  	struct clk *clk_2x_enable;
> +	struct pinctrl *pinctrl;
> +	struct pinctrl_state *pins_uhs;
> +	struct pinctrl_state *pins_default;
>  	u32 base_rate;
>  	int flags; /* backup of host attribute */
>  	u32 phy_delay[MMC_TIMING_MMC_HS400 + 2];
> @@ -405,6 +409,8 @@ static void sdhci_sprd_request(struct mmc_host *mmc, struct mmc_request *mrq)
>  
>  static int sdhci_sprd_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
>  {
> +	struct sdhci_host *host = mmc_priv(mmc);
> +	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
>  	int ret;
>  
>  	if (!IS_ERR(mmc->supply.vqmmc)) {
> @@ -416,6 +422,37 @@ static int sdhci_sprd_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
>  		}
>  	}
>  
> +	if (IS_ERR(sprd_host->pinctrl))
> +		return 0;
> +
> +	switch (ios->signal_voltage) {
> +	case MMC_SIGNAL_VOLTAGE_180:
> +		ret = pinctrl_select_state(sprd_host->pinctrl,
> +					   sprd_host->pins_uhs);
> +		if (ret) {
> +			pr_err("%s: failed to select uhs pin state\n",
> +			       mmc_hostname(mmc));
> +			return ret;
> +		}
> +		break;
> +
> +	default:
> +		/* fall-through */
> +	case MMC_SIGNAL_VOLTAGE_330:
> +		ret = pinctrl_select_state(sprd_host->pinctrl,
> +					   sprd_host->pins_default);
> +		if (ret) {
> +			pr_err("%s: failed to select default pin state\n",
> +			       mmc_hostname(mmc));
> +			return ret;
> +		}
> +		break;
> +	}
> +
> +	/* Wait for 300 ~ 500 us for pin state stable */
> +	usleep_range(300, 500);
> +	sdhci_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
> +
>  	return 0;
>  }
>  
> @@ -504,6 +541,23 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
>  	sprd_host = TO_SPRD_HOST(host);
>  	sdhci_sprd_phy_param_parse(sprd_host, pdev->dev.of_node);
>  
> +	sprd_host->pinctrl = devm_pinctrl_get(&pdev->dev);
> +	if (!IS_ERR(sprd_host->pinctrl)) {
> +		sprd_host->pins_uhs =
> +			pinctrl_lookup_state(sprd_host->pinctrl, "state_uhs");
> +		if (IS_ERR(sprd_host->pins_uhs)) {
> +			ret = PTR_ERR(sprd_host->pins_uhs);
> +			goto pltfm_free;
> +		}
> +
> +		sprd_host->pins_default =
> +			pinctrl_lookup_state(sprd_host->pinctrl, "default");
> +		if (IS_ERR(sprd_host->pins_default)) {
> +			ret = PTR_ERR(sprd_host->pins_default);
> +			goto pltfm_free;
> +		}
> +	}
> +
>  	clk = devm_clk_get(&pdev->dev, "sdio");
>  	if (IS_ERR(clk)) {
>  		ret = PTR_ERR(clk);
>