Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver

From: Kishon Vijay Abraham I <kishon@ti.com>
To: Adrian Hunter <adrian.hunter@intel.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	Rob Herring <robh+dt@kernel.org>
Cc: <nsekhar@ti.com>, <linux-omap@vger.kernel.org>,
	<linux-mmc@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver
Date: Thu, 17 Aug 2017 11:27:33 +0530	[thread overview]
Message-ID: <46568bdf-c11f-e04b-edd4-25d5363ae504@ti.com> (raw)
In-Reply-To: <a45cf402-26c9-d9d0-1ca0-cbeeddad388c@intel.com>

Hi Adrian,

On Tuesday 15 August 2017 01:52 PM, Adrian Hunter wrote:
> On 07/08/17 19:01, Kishon Vijay Abraham I wrote:
>> Create a new sdhci-omap driver to configure the eMMC/SD/SDIO controller
>> in TI's OMAP SoCs making use of the SDHCI core library. For OMAP specific
>> configurations, populate sdhci_ops with OMAP specific callbacks and use
>> SDHCI quirks.
>> Enable only high speed mode for both SD and eMMC here and add other
>> UHS mode support later.
> 
> I only have a couple of comments below.
> 
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
>> ---
>>  drivers/mmc/host/Kconfig      |  12 +
>>  drivers/mmc/host/Makefile     |   1 +
>>  drivers/mmc/host/sdhci-omap.c | 593 ++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 606 insertions(+)
>>  create mode 100644 drivers/mmc/host/sdhci-omap.c
>>
>> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
>> index 5755b69f2f72..9aa7e5ce43ba 100644
>> --- a/drivers/mmc/host/Kconfig
>> +++ b/drivers/mmc/host/Kconfig
>> @@ -871,3 +871,15 @@ config MMC_SDHCI_XENON
>>  	  This selects Marvell Xenon eMMC/SD/SDIO SDHCI.
>>  	  If you have a controller with this interface, say Y or M here.
>>  	  If unsure, say N.
>> +
>> +config MMC_SDHCI_OMAP
>> +	tristate "TI SDHCI Controller Support"
>> +	depends on MMC_SDHCI_PLTFM
>> +	help
>> +	  This selects the Secure Digital Host Controller Interface (SDHCI)
>> +	  support present in TI's DRA7 SOCs. The controller supports
>> +	  SD/MMC/SDIO devices.
>> +
>> +	  If you have a controller with this interface, say Y or M here.
>> +
>> +	  If unsure, say N.
>> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
>> index 4d4547116311..30fb8b0fd0e1 100644
>> --- a/drivers/mmc/host/Makefile
>> +++ b/drivers/mmc/host/Makefile
>> @@ -82,6 +82,7 @@ obj-$(CONFIG_MMC_SDHCI_MSM)		+= sdhci-msm.o
>>  obj-$(CONFIG_MMC_SDHCI_ST)		+= sdhci-st.o
>>  obj-$(CONFIG_MMC_SDHCI_MICROCHIP_PIC32)	+= sdhci-pic32.o
>>  obj-$(CONFIG_MMC_SDHCI_BRCMSTB)		+= sdhci-brcmstb.o
>> +obj-$(CONFIG_MMC_SDHCI_OMAP)		+= sdhci-omap.o
>>  
>>  ifeq ($(CONFIG_CB710_DEBUG),y)
>>  	CFLAGS-cb710-mmc	+= -DDEBUG
>> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
>> new file mode 100644
>> index 000000000000..c067c428a0cd
>> --- /dev/null
>> +++ b/drivers/mmc/host/sdhci-omap.c
>> @@ -0,0 +1,593 @@
>> +/*
>> + * SDHCI Controller driver for TI's OMAP SoCs
>> + *
>> + * Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com
>> + *
>> + * Authors: Kishon Vijay Abraham I <kishon@ti.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/mmc/slot-gpio.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#include "sdhci-pltfm.h"
>> +
>> +#define SDHCI_OMAP_CON		0x12c
>> +#define CON_DW8			BIT(5)
>> +#define CON_DMA_MASTER		BIT(20)
>> +#define CON_INIT		BIT(1)
>> +#define CON_OD			BIT(0)
>> +
>> +#define SDHCI_OMAP_CMD		0x20c
>> +
>> +#define SDHCI_OMAP_HCTL		0x228
>> +#define HCTL_SDBP		BIT(8)
>> +#define HCTL_SDVS_SHIFT		9
>> +#define HCTL_SDVS_MASK		(0x7 << HCTL_SDVS_SHIFT)
>> +#define HCTL_SDVS_33		(0x7 << HCTL_SDVS_SHIFT)
>> +#define HCTL_SDVS_30		(0x6 << HCTL_SDVS_SHIFT)
>> +#define HCTL_SDVS_18		(0x5 << HCTL_SDVS_SHIFT)
>> +
>> +#define SDHCI_OMAP_SYSCTL	0x22c
>> +#define SYSCTL_CEN		BIT(2)
>> +#define SYSCTL_CLKD_SHIFT	6
>> +#define SYSCTL_CLKD_MASK	0x3ff
>> +
>> +#define SDHCI_OMAP_STAT		0x230
>> +
>> +#define SDHCI_OMAP_IE		0x234
>> +#define INT_CC_EN		BIT(0)
>> +
>> +#define SDHCI_OMAP_AC12		0x23c
>> +#define AC12_V1V8_SIGEN		BIT(19)
>> +
>> +#define SDHCI_OMAP_CAPA		0x240
>> +#define CAPA_VS33		BIT(24)
>> +#define CAPA_VS30		BIT(25)
>> +#define CAPA_VS18		BIT(26)
>> +
>> +#define MMC_TIMEOUT		1		/* 1 msec */
> 
> This name "MMC_TIMEOUT" is too generic.  SDHCI_OMAP_TIMEOUT would be better.

okay.
> 
>> +
>> +#define SYSCTL_CLKD_MAX		0x3FF
>> +
>> +#define IOV_1V8			1800000		/* 180000 uV */
>> +#define IOV_3V0			3000000		/* 300000 uV */
>> +#define IOV_3V3			3300000		/* 330000 uV */
>> +
>> +struct sdhci_omap_data {
>> +	u32 offset;
>> +};
>> +
>> +struct sdhci_omap_host {
>> +	void __iomem		*base;
>> +	struct device		*dev;
>> +	struct	regulator	*pbias;
>> +	bool			pbias_enabled;
>> +	struct sdhci_host	*host;
>> +	unsigned int		flags;
>> +
>> +#define SDHCI_OMAP_SUPPORTS_DUAL_VOLT	BIT(0)
>> +#define SDHCI_OMAP_NO_1_8_V		BIT(1)
>> +
>> +	u8			power_mode;
>> +	bool			io_3_3v_support;
>> +};
>> +
.
.
<<snip>>
.
.
>> +static int sdhci_omap_probe(struct platform_device *pdev)
>> +{
>> +	int ret;
>> +	u32 offset;
>> +	struct device *dev = &pdev->dev;
>> +	struct sdhci_host *host;
>> +	struct sdhci_pltfm_host *pltfm_host;
>> +	struct sdhci_omap_host *omap_host;
>> +	struct mmc_host *mmc;
>> +	const struct of_device_id *match;
>> +	struct sdhci_omap_data *data;
>> +
>> +	match = of_match_device(omap_sdhci_match, dev);
>> +	if (!match)
>> +		return -EINVAL;
>> +
>> +	data = (struct sdhci_omap_data *)match->data;
>> +	if (!data) {
>> +		dev_err(dev, "no sdhci omap data\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	offset = data->offset;
>> +
>> +	host = sdhci_pltfm_init(pdev, &sdhci_omap_pdata,
>> +				sizeof(*omap_host));
>> +	if (IS_ERR(host)) {
>> +		dev_err(dev, "Failed sdhci_pltfm_init\n");
>> +		return PTR_ERR(host);
>> +	}
>> +
>> +	pltfm_host = sdhci_priv(host);
>> +	omap_host = sdhci_pltfm_priv(pltfm_host);
>> +	omap_host->host = host;
>> +	omap_host->base = host->ioaddr;
>> +	omap_host->dev = dev;
>> +	sdhci_omap_get_of_property(omap_host);
>> +
>> +	host->ioaddr += offset;
>> +
>> +	mmc = host->mmc;
>> +	ret = mmc_of_parse(mmc);
>> +	if (ret)
>> +		goto err_of_parse;
>> +
>> +	pltfm_host->clk = devm_clk_get(dev, "fck");
>> +	if (IS_ERR(pltfm_host->clk)) {
>> +		ret = PTR_ERR(pltfm_host->clk);
>> +		goto err_of_parse;
>> +	}
>> +
>> +	ret = clk_set_rate(pltfm_host->clk, mmc->f_max);
>> +	if (ret) {
>> +		dev_err(dev, "failed to set clock to %d\n", mmc->f_max);
>> +		goto err_of_parse;
>> +	}
>> +
>> +	omap_host->pbias = devm_regulator_get_optional(dev, "pbias");
>> +	if (IS_ERR(omap_host->pbias)) {
>> +		ret = PTR_ERR(omap_host->pbias);
>> +		if (ret != -ENODEV) {
>> +			dev_err(dev, "CONFIG_REGULATOR_PBIAS not enabled??\n");
>> +			return ret;
>> +		}
>> +		dev_dbg(dev, "unable to get pbias regulator %ld\n",
>> +			PTR_ERR(omap_host->pbias));
>> +	} else {
>> +		if (regulator_is_supported_voltage(omap_host->pbias, IOV_3V3,
>> +						   IOV_3V3))
>> +			omap_host->io_3_3v_support = true;
>> +		dev_vdbg(dev, "Max PBIAS support Voltage: %dmv\n",
>> +			 omap_host->io_3_3v_support ? IOV_3V3 : IOV_3V0);
>> +	}
>> +	omap_host->pbias_enabled = false;
>> +
>> +	pm_runtime_enable(dev);
>> +	ret = pm_runtime_get_sync(dev);
> 
> What are you trying to do with runtime pm?  There don't seem to be any pm
> callbacks, so does this do anything?

yeah, pm_runtime_get_sync enables the functional clock and also configures the
SYSCONFIG regiters present in the controller. It gets the details for
configuring those from arch/arm/mach-omap2/omap_hwmod_*

Thanks
Kishon