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Subject: Re: [PATCH V1 3/3] mmc: sdhci-msm: Use internal voltage control
To:     Adrian Hunter <adrian.hunter@intel.com>,
        Vijay Viswanath <vviswana@codeaurora.org>,
        ulf.hansson@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        shawn.lin@rock-chips.com, linux-arm-msm@vger.kernel.org,
        georgi.djakov@linaro.org, devicetree@vger.kernel.org,
        asutoshd@codeaurora.org, stummala@codeaurora.org,
        venkatg@codeaurora.org, jeremymc@redhat.com,
        bjorn.andersson@linaro.org, riteshh@codeaurora.org,
        evgreen@chromium.org, dianders@google.com, sayalil@codeaurora.org
References: <1532083566-43215-1-git-send-email-vviswana@codeaurora.org>
 <1532083566-43215-4-git-send-email-vviswana@codeaurora.org>
 <0a5317f1-b75a-5286-2a53-2fe14b67a77a@intel.com>
From:   Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Message-ID: <45f078fa-d396-02a7-5e85-dbb8c824136a@codeaurora.org>
Date:   Tue, 18 Sep 2018 17:05:14 +0530
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Hi Adrian,


On 7/25/2018 7:34 PM, Adrian Hunter wrote:
> On 20/07/18 13:46, Vijay Viswanath wrote:
>> Some sdhci-msm controllers require that voltage switching be done after
>> the HW is ready for it. The HW informs its readiness through power irq.
>> The voltage switching should happen only then.
>>
>> Use the quirk for internal voltage switching and then control the
>> voltage switching using power irq.
>>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>> ---
>>   drivers/mmc/host/sdhci-msm.c | 220 ++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 209 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
>> index a0dc3e1..47732a2 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -43,7 +43,9 @@
>>   #define CORE_PWRCTL_IO_LOW	BIT(2)
>>   #define CORE_PWRCTL_IO_HIGH	BIT(3)
>>   #define CORE_PWRCTL_BUS_SUCCESS BIT(0)
>> +#define CORE_PWRCTL_BUS_FAIL    BIT(1)
>>   #define CORE_PWRCTL_IO_SUCCESS	BIT(2)
>> +#define CORE_PWRCTL_IO_FAIL     BIT(3)
>>   #define REQ_BUS_OFF		BIT(0)
>>   #define REQ_BUS_ON		BIT(1)
>>   #define REQ_IO_LOW		BIT(2)
>> @@ -236,6 +238,14 @@ struct sdhci_msm_variant_info {
>>   	const struct sdhci_msm_offset *offset;
>>   };
>>   
>> +/* Holds voltage regulator information to be used by the driver*/
>> +struct sdhci_msm_vreg_info {
>> +	bool vmmc_load;
>> +	u32 vmmc_level[2];
>> +	bool vqmmc_load;
>> +	u32 vqmmc_level[2];
>> +};
> Kernel style is not to introduce structures that are only ever wholly
> contained within one other structure i.e. the members of struct
> sdhci_msm_vreg_info could just be in struct sdhci_msm_host instead.
Sure. Will move this to sdhci_msm_host
>> +
>>   struct sdhci_msm_host {
>>   	struct platform_device *pdev;
>>   	void __iomem *core_mem;	/* MSM SDCC mapped address */
>> @@ -258,6 +268,8 @@ struct sdhci_msm_host {
>>   	bool mci_removed;
>>   	const struct sdhci_msm_variant_ops *var_ops;
>>   	const struct sdhci_msm_offset *offset;
>> +	struct sdhci_msm_vreg_info vreg_info;
>> +	bool pltfm_init_done;
>>   };
>>   
>>   static const struct sdhci_msm_offset *sdhci_priv_msm_offset(struct sdhci_host *host)
>> @@ -1314,11 +1326,13 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
>>   {
>>   	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>>   	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
>> +	struct mmc_host *mmc = host->mmc;
>>   	u32 irq_status, irq_ack = 0;
>> -	int retry = 10;
>> +	int retry = 10, ret = 0;
>>   	u32 pwr_state = 0, io_level = 0;
>>   	u32 config;
>>   	const struct sdhci_msm_offset *msm_offset = msm_host->offset;
>> +	struct sdhci_msm_vreg_info vreg_info = msm_host->vreg_info;
>>   
>>   	irq_status = msm_host_readl(msm_host, host,
>>   			msm_offset->core_pwrctl_status);
>> @@ -1351,14 +1365,91 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
>>   
>>   	/* Handle BUS ON/OFF*/
>>   	if (irq_status & CORE_PWRCTL_BUS_ON) {
>> -		pwr_state = REQ_BUS_ON;
>> -		io_level = REQ_IO_HIGH;
>> -		irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
>> +		if (!IS_ERR(mmc->supply.vmmc)) {
>> +			if (vreg_info.vmmc_load)
>> +				ret = regulator_set_load(mmc->supply.vmmc,
>> +						vreg_info.vmmc_level[1]);
>> +			ret |= mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
>> +					mmc->ios.vdd);
> Or-ing error numbers seems a bit weird.  The code is a bit crammed also,
> so I suggest adding helper functions.  For example consider something like:
>
> static int sdhci_msm_set_vmmc(struct sdhci_msm_host *msm_host,
> 			      struct mmc_host *mmc, int level)
> {
> 	int load = msm_host->vmmc_level[level];
> 	int ret;
>
> 	if (IS_ERR(mmc->supply.vmmc))
> 		return 0;
>
> 	if (msm_host->vmmc_load) {
> 		ret = regulator_set_load(mmc->supply.vmmc, load);
> 		if (ret)
> 			goto out;
> 	}
>
> 	ret = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, mmc->ios.vdd);
> out:
> 	if (ret)
> 		pr_err("%s: vmmc failed: %d\n", mmc_hostname(mmc), ret);
>
> 	return ret;
> }
Will update it as suggested.
>> +			if (ret)
>> +				pr_err("%s: vmmc enable failed: %d\n",
>> +						mmc_hostname(mmc), ret);
>> +		}
>> +
>> +		if (!IS_ERR(mmc->supply.vqmmc) && !ret) {
>> +			struct mmc_ios ios;
>> +
>> +			if (vreg_info.vqmmc_load)
>> +				ret = regulator_set_load(mmc->supply.vqmmc,
>> +						vreg_info.vqmmc_level[1]);
>> +			/*
>> +			 * The IO voltage regulator maynot always support
>> +			 * a voltage close to vdd. Set IO voltage based on
>> +			 * capability of the regulator.
>> +			 */
>> +			if (msm_host->caps_0 & CORE_3_0V_SUPPORT)
>> +				ios.signal_voltage = MMC_SIGNAL_VOLTAGE_330;
>> +			else if (msm_host->caps_0 & CORE_1_8V_SUPPORT)
>> +				ios.signal_voltage = MMC_SIGNAL_VOLTAGE_180;
>> +			if (msm_host->caps_0 & CORE_VOLT_SUPPORT) {
>> +				pr_err("%s: %s: setting signal voltage: %d\n",
>> +						mmc_hostname(mmc), __func__,
>> +						ios.signal_voltage);
> Why pr_err()?
This need not be pr_err. Will change it to pr_debug().
>> +				ret |= mmc_regulator_set_vqmmc(mmc, &ios);
> Again I suggest createing a helper function and not or-ing error numbers.
>
>> +			}
>> +
>> +			if (!ret)
>> +				ret = regulator_enable(mmc->supply.vqmmc);
>> +			if (ret)
>> +				pr_err("%s: vqmmc enable failed: %d\n",
>> +						mmc_hostname(mmc), ret);
>> +		}
>> +		if (!ret) {
>> +			pwr_state = REQ_BUS_ON;
>> +			io_level = REQ_IO_HIGH;
>> +			irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
>> +		} else {
>> +			pr_err("%s: BUS_ON req failed(%d). irq_status: 0x%08x\n",
>> +					mmc_hostname(mmc), ret, irq_status);
>> +			irq_ack |= CORE_PWRCTL_BUS_FAIL;
>> +		}
>>   	}
>>   	if (irq_status & CORE_PWRCTL_BUS_OFF) {
>> -		pwr_state = REQ_BUS_OFF;
>> -		io_level = REQ_IO_LOW;
>> -		irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
>> +		/*
>> +		 * During platform initialization, we may get BUS_OFF request
>> +		 * and turn off the supply. EMMC devices expect Power off
>> +		 * notification before being turned off. So wait till platform
>> +		 * initialization is over to actually turn off power.
>> +		 */
>> +		if (!IS_ERR(mmc->supply.vmmc) && msm_host->pltfm_init_done) {
>> +			if (vreg_info.vmmc_load)
>> +				ret = regulator_set_load(mmc->supply.vmmc,
>> +						vreg_info.vmmc_level[0]);
>> +			ret |= mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
>> +					mmc->ios.vdd);
>> +			if (ret)
>> +				pr_err("%s: vmmc disabling failed: %d\n",
>> +						mmc_hostname(mmc), ret);
>> +		}
> So with the function above, that would be:
>
> 		if (msm_host->pltfm_init_done)
> 			ret = sdhci_msm_set_vmmc(msm_host, mmc, 0)
>
>> +		if (!IS_ERR(mmc->supply.vqmmc) && msm_host->pltfm_init_done &&
>> +				!ret) {
>> +			if (vreg_info.vqmmc_load)
>> +				ret = regulator_set_load(mmc->supply.vqmmc,
>> +						vreg_info.vqmmc_level[0]);
>> +			ret |= regulator_disable(mmc->supply.vqmmc);
>> +			if (ret)
>> +				pr_err("%s: vqmmc disabling failed: %d\n",
>> +						mmc_hostname(mmc), ret);
>> +		}
>> +		if (!ret) {
>> +			pwr_state = REQ_BUS_OFF;
>> +			io_level = REQ_IO_LOW;
>> +			irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
>> +		} else {
>> +			pr_err("%s: BUS_ON req failed(%d). irq_status: 0x%08x\n",
>> +					mmc_hostname(mmc), ret, irq_status);
>> +			irq_ack |= CORE_PWRCTL_BUS_FAIL;
>> +		}
>>   	}
>>   	/* Handle IO LOW/HIGH */
>>   	if (irq_status & CORE_PWRCTL_IO_LOW) {
>> @@ -1370,6 +1461,15 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
>>   		irq_ack |= CORE_PWRCTL_IO_SUCCESS;
>>   	}
>>   
>> +	if (io_level && !IS_ERR(mmc->supply.vqmmc) && !pwr_state) {
>> +		ret = mmc_regulator_set_vqmmc(mmc, &mmc->ios);
>> +		if (ret)
>> +			pr_err("%s: IO_level setting failed(%d). signal_voltage: %d, vdd: %d irq_status: 0x%08x\n",
>> +					mmc_hostname(mmc), ret,
>> +					mmc->ios.signal_voltage, mmc->ios.vdd,
>> +					irq_status);
>> +	}
>> +
>>   	/*
>>   	 * The driver has to acknowledge the interrupt, switch voltages and
>>   	 * report back if it succeded or not to this register. The voltage
>> @@ -1415,10 +1515,9 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
>>   		msm_host->curr_pwr_state = pwr_state;
>>   	if (io_level)
>>   		msm_host->curr_io_level = io_level;
>> -
>>   	pr_debug("%s: %s: Handled IRQ(%d), irq_status=0x%x, ack=0x%x\n",
>> -		mmc_hostname(msm_host->mmc), __func__, irq, irq_status,
>> -		irq_ack);
>> +			mmc_hostname(msm_host->mmc), __func__,
>> +			irq, irq_status, irq_ack);
> Seem to be some unrelated whitespace changes here.
>
>>   }
>>   
>>   static irqreturn_t sdhci_msm_pwr_irq(int irq, void *data)
>> @@ -1563,6 +1662,13 @@ static void sdhci_msm_writeb(struct sdhci_host *host, u8 val, int reg)
>>   		sdhci_msm_check_power_status(host, req_type);
>>   }
>>   
>> +static void sdhci_msm_set_power(struct sdhci_host *host, unsigned char mode,
>> +		     unsigned short vdd)
>> +{
>> +	sdhci_set_power_noreg(host, mode, vdd);
> Why not just have .set_power = sdhci_set_power_noreg()
You are right. Will remove  sdhci_msm_set_power()
>
>> +
>> +}
>> +
>>   static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
>>   {
>>   	struct mmc_host *mmc = msm_host->mmc;
>> @@ -1605,6 +1711,91 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
>>   	pr_debug("%s: supported caps: 0x%08x\n", mmc_hostname(mmc), caps);
>>   }
>>   
>> +static int sdhci_msm_register_vreg(struct sdhci_msm_host *msm_host)
>> +{
>> +	int ret = 0;
>> +
>> +	ret = mmc_regulator_get_supply(msm_host->mmc);
>> +	if (ret)
>> +		return ret;
>> +	if (device_property_read_u32_array(&msm_host->pdev->dev,
>> +			"vmmc-current-level",
>> +			msm_host->vreg_info.vmmc_level, 2) >= 0)
>> +		msm_host->vreg_info.vmmc_load = true;
>> +	if (device_property_read_u32_array(&msm_host->pdev->dev,
>> +			"vqmmc-current-level",
>> +			msm_host->vreg_info.vqmmc_level, 2) >= 0)
>> +		msm_host->vreg_info.vqmmc_load = true;
>> +
>> +	sdhci_msm_set_regulator_caps(msm_host);
>> +
>> +	return 0;
>> +
>> +}
>> +
>> +static int sdhci_msm_start_signal_voltage_switch(struct mmc_host *mmc,
>> +				      struct mmc_ios *ios)
>> +{
>> +	struct sdhci_host *host = mmc_priv(mmc);
>> +	u16 ctrl;
>> +
>> +	/*
>> +	 * Signal Voltage Switching is only applicable for Host Controllers
>> +	 * v3.00 and above.
>> +	 */
>> +	if (host->version < SDHCI_SPEC_300)
>> +		return 0;
>> +
>> +	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> +
>> +	switch (ios->signal_voltage) {
>> +	case MMC_SIGNAL_VOLTAGE_330:
>> +		if (!(host->flags & SDHCI_SIGNALING_330))
>> +			return -EINVAL;
>> +		/* Set 1.8V Signal Enable in the Host Control2 register to 0 */
>> +		ctrl &= ~SDHCI_CTRL_VDD_180;
>> +		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>> +
>> +		/* 3.3V regulator output should be stable within 5 ms */
>> +		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> +		if (!(ctrl & SDHCI_CTRL_VDD_180))
>> +			return 0;
>> +
>> +		pr_warn("%s: 3.3V regulator output did not became stable\n",
>> +			mmc_hostname(mmc));
>> +
>> +		return -EAGAIN;
>> +	case MMC_SIGNAL_VOLTAGE_180:
>> +		if (!(host->flags & SDHCI_SIGNALING_180))
>> +			return -EINVAL;
>> +
>> +		/*
>> +		 * Enable 1.8V Signal Enable in the Host Control2
>> +		 * register
>> +		 */
>> +		ctrl |= SDHCI_CTRL_VDD_180;
>> +		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>> +
>> +		/* 1.8V regulator output should be stable within 5 ms */
>> +		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>> +		if (ctrl & SDHCI_CTRL_VDD_180)
>> +			return 0;
>> +
>> +		pr_warn("%s: 1.8V regulator output did not became stable\n",
>> +			mmc_hostname(mmc));
>> +
>> +		return -EAGAIN;
>> +	case MMC_SIGNAL_VOLTAGE_120:
>> +		if (!(host->flags & SDHCI_SIGNALING_120))
>> +			return -EINVAL;
>> +		return 0;
>> +	default:
>> +		/* No signal voltage switch required */
>> +		return 0;
>> +	}
>> +
>> +}
>> +
>>   static const struct sdhci_msm_variant_ops mci_var_ops = {
>>   	.msm_readl_relaxed = sdhci_msm_mci_variant_readl_relaxed,
>>   	.msm_writel_relaxed = sdhci_msm_mci_variant_writel_relaxed,
>> @@ -1644,6 +1835,7 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
>>   	.set_uhs_signaling = sdhci_msm_set_uhs_signaling,
>>   	.write_w = sdhci_msm_writew,
>>   	.write_b = sdhci_msm_writeb,
>> +	.set_power = sdhci_msm_set_power,
>>   };
>>   
>>   static const struct sdhci_pltfm_data sdhci_msm_pdata = {
>> @@ -1672,6 +1864,8 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>>   	if (IS_ERR(host))
>>   		return PTR_ERR(host);
>>   
>> +	host->mmc_host_ops.start_signal_voltage_switch =
>> +		sdhci_msm_start_signal_voltage_switch;
> Perhaps put this where the other mmc_host_ops assignment is.
sure. Will move it.
>>   	host->sdma_boundary = 0;
>>   	pltfm_host = sdhci_priv(host);
>>   	msm_host = sdhci_pltfm_priv(pltfm_host);
>> @@ -1819,6 +2013,10 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>>   				msm_offset->core_vendor_spec_capabilities0);
>>   	}
>>   
>> +	ret = sdhci_msm_register_vreg(msm_host);
>> +	if (ret == -EPROBE_DEFER)
> Why not just:
>
> 	if (ret)
>
>> +		goto clk_disable;
>> +
>>   	/*
>>   	 * Power on reset state may trigger power irq if previous status of
>>   	 * PWRCTL was either BUS_ON or IO_HIGH_V. So before enabling pwr irq
>> @@ -1867,7 +2065,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>>   	ret = sdhci_add_host(host);
>>   	if (ret)
>>   		goto pm_runtime_disable;
>> -	sdhci_msm_set_regulator_caps(msm_host);
>> +	msm_host->pltfm_init_done = true;
>>   
>>   	pm_runtime_mark_last_busy(&pdev->dev);
>>   	pm_runtime_put_autosuspend(&pdev->dev);
>>
Thanks for all the comments. Will incorporate all the commented changes.
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