Message-ID: <52386D64.4030306@mm-sol.com>
Date:	Tue, 17 Sep 2013 17:55:32 +0300
From:	Stanimir Varbanov <svarbanov@...sol.com>
To:	Georgi Djakov <gdjakov@...sol.com>
CC:	linux-mmc@...r.kernel.org, cjb@...top.org, grant.likely@...aro.org,
	rob.herring@...xeda.com, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	Asutosh Das <asutoshd@...eaurora.org>,
	Venkat Gopalakrishnan <venkatg@...eaurora.org>,
	Sahitya Tummala <stummala@...eaurora.org>,
	Subhash Jadavani <subhashj@...eaurora.org>
Subject: Re: [PATCH v5] mmc: sdhci-msm: Add support for MSM chipsets

Hi Georgi,

Thanks for the patch.

I have some commnets below.

On 09/16/2013 05:23 PM, Georgi Djakov wrote:
> This platform driver adds the support of Secure Digital Host Controller
> Interface compliant controller found in Qualcomm MSM chipsets.
> 
> CC: Asutosh Das <asutoshd@...eaurora.org>
> CC: Venkat Gopalakrishnan <venkatg@...eaurora.org>
> CC: Sahitya Tummala <stummala@...eaurora.org>
> CC: Subhash Jadavani <subhashj@...eaurora.org>
> Signed-off-by: Georgi Djakov <gdjakov@...sol.com>
> ---
> Changes from v4:
> - Simplified sdhci_msm_vreg_disable() and sdhci_msm_set_vdd_io_vol()
> - Use devm_ioremap_resource() instead of devm_ioremap()
> - Converted IS_ERR_OR_NULL to IS_ERR
> - Disable regulators in sdhci_msm_remove()
> - Check for DT node at the beginning in sdhci_msm_probe()
> - Removed more redundant code
> - Changes in some error messages
> - Minor fixes
> 
> Changes from v3:
> - Allocate memory for all required structs at once
> - Added termination entry in sdhci_msm_dt_match[]
> - Fixed a missing sdhci_pltfm_free() in probe()
> - Removed redundant of_match_ptr
> - Removed the unneeded function sdhci_msm_vreg_reset()
> 
> Changes from v2:
> - Added DT bindings for clocks
> - Moved voltage regulators data to platform data
> - Removed unneeded includes
> - Removed obsolete and wrapper functions
> - Removed error checking where unnecessary
> - Removed redundant _clk suffix from clock names
> - Just return instead of goto where possible
> - Minor fixes
> 
> Changes from v1:
> - GPIO references are replaced by pinctrl
> - DT parsing is done mostly by mmc_of_parse()
> - Use of_match_device() for DT matching
> - A few minor changes
> 
>  .../devicetree/bindings/mmc/sdhci-msm.txt          |   71 +++
>  drivers/mmc/host/Kconfig                           |   13 +
>  drivers/mmc/host/Makefile                          |    1 +
>  drivers/mmc/host/sdhci-msm.c                       |  627 ++++++++++++++++++++
>  4 files changed, 712 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mmc/sdhci-msm.txt
>  create mode 100644 drivers/mmc/host/sdhci-msm.c
> 
> diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
> new file mode 100644
> index 0000000..ee112da
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
> @@ -0,0 +1,71 @@
> +* Qualcomm SDHCI controller (sdhci-msm)
> +
> +This file documents differences between the core properties in mmc.txt
> +and the properties used by the sdhci-msm driver.
> +
> +Required properties:
> +- compatible: should be "qcom,sdhci-msm"
> +- reg: should contain SDHC, SD Core register map
> +- reg-names: indicates various resources passed to driver (via reg proptery) by name
> +	"reg-names" examples are "hc_mem" and "core_mem"
> +- interrupts: should contain SDHC interrupts
> +- interrupt-names: indicates interrupts passed to driver (via interrupts property) by name
> +	"interrupt-names" examples are "hc_irq" and "pwr_irq"
> +- <supply-name>-supply: phandle to the regulator device tree node
> +	"supply-name" examples are "vdd" and "vdd-io"
> +- pinctrl-names: Should contain only one value - "default".
> +- pinctrl-0: Should specify pin control groups used for this controller.
> +- clocks: phandles to clock instances of the device tree nodes
> +- clock-names:
> +	iface: Main peripheral bus clock (PCLK/HCLK - AHB Bus clock) (required)
> +	core: SDC MMC clock (MCLK) (required)
> +	bus: SDCC bus voter clock (optional)
> +
> +Optional properties:
> +- qcom,bus-speed-mode - specifies supported bus speed modes by host
> +	The supported bus speed modes are :
> +	"HS200_1p8v" - indicates that host can support HS200 at 1.8v
> +	"HS200_1p2v" - indicates that host can support HS200 at 1.2v
> +	"DDR_1p8v" - indicates that host can support DDR mode at 1.8v
> +	"DDR_1p2v" - indicates that host can support DDR mode at 1.2v
> +
> +In the following, <supply> can be vdd (flash core voltage) or vdd-io (I/O voltage).
> +- qcom,<supply>-always-on - specifies whether supply should be kept "on" always.
> +- qcom,<supply>-lpm-sup - specifies whether supply can be kept in low power mode (lpm).
> +- qcom,<supply>-voltage-level - specifies voltage levels for supply. Should be
> +specified in pairs (min, max), units uV.
> +- qcom,<supply>-current-level - specifies load levels for supply in lpm or high power mode
> +	(hpm). Should be specified in pairs (lpm, hpm), units uA.
> +
> +Example:
> +
> +	aliases {
> +		sdhc1 = &sdhc_1;
> +	};
> +
> +	sdhc_1: qcom,sdhc@...24900 {
> +		compatible = "qcom,sdhci-msm";
> +		reg = <0xf9824900 0x11c>, <0xf9824000 0x800>;
> +		reg-names = "hc_mem", "core_mem";
> +		interrupts = <0 123 0>, <0 138 0>;
> +		interrupt-names = "hc_irq", "pwr_irq";
> +		bus-width = <4>;
> +		non-removable;
> +
> +		vdd-supply = <&pm8941_l21>;
> +		vdd-io-supply = <&pm8941_l13>;
> +		qcom,vdd-voltage-level = <2950000 2950000>;
> +		qcom,vdd-current-level = <9000 800000>;
> +		qcom,vdd-io-always-on;
> +		qcom,vdd-io-lpm-sup;
> +		qcom,vdd-io-voltage-level = <1800000 2950000>;
> +		qcom,vdd-io-current-level = <6 22000>;
> +		qcom,bus-speed-mode = "HS200_1p8v", "DDR_1p8v";
> +
> +		pinctrl-names = "default";
> +		pinctrl-0 = <&sdc1_clk &sdc1_cmd &sdc1_data>;
> +
> +		clocks = <&iface>, <&core>, <&bus>;
> +		clock-names = "iface", "core", "bus";
> +
> +	};
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 7fc5099..e8da488 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -322,6 +322,19 @@ config MMC_ATMELMCI
>  
>  	  If unsure, say N.
>  
> +config MMC_SDHCI_MSM
> +	tristate "Qualcomm SDHCI Controller Support"
> +	depends on ARCH_MSM
> +	depends on MMC_SDHCI_PLTFM
> +	help
> +	  This selects the Secure Digital Host Controller Interface (SDHCI)
> +	  support present in MSM SOCs from Qualcomm. The controller
> +	  supports SD/MMC/SDIO devices.
> +
> +	  If you have a controller with this interface, say Y or M here.
> +
> +	  If unsure, say N.
> +
>  config MMC_MSM
>  	tristate "Qualcomm SDCC Controller Support"
>  	depends on MMC && ARCH_MSM
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index c41d0c3..5faed14 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_MMC_SDHCI_OF_ESDHC)	+= sdhci-of-esdhc.o
>  obj-$(CONFIG_MMC_SDHCI_OF_HLWD)		+= sdhci-of-hlwd.o
>  obj-$(CONFIG_MMC_SDHCI_BCM_KONA)	+= sdhci-bcm-kona.o
>  obj-$(CONFIG_MMC_SDHCI_BCM2835)		+= sdhci-bcm2835.o
> +obj-$(CONFIG_MMC_SDHCI_MSM)		+= sdhci-msm.o
>  
>  ifeq ($(CONFIG_CB710_DEBUG),y)
>  	CFLAGS-cb710-mmc	+= -DDEBUG
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> new file mode 100644
> index 0000000..c746a9b
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -0,0 +1,627 @@
> +/*
> + * drivers/mmc/host/sdhci-msm.c - Qualcomm MSM SDHCI Platform
> + * driver source file
> + *
> + * Copyright (c) 2013, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include "sdhci-pltfm.h"
> +
> +#define CORE_HC_MODE		0x78
> +#define HC_MODE_EN		0x1
> +
> +#define CORE_POWER		0x0
> +#define CORE_SW_RST		(1 << 7)
> +
> +#define CORE_PWRCTL_STATUS	0xdc
> +#define CORE_PWRCTL_MASK	0xe0
> +#define CORE_PWRCTL_CLEAR	0xe4
> +#define CORE_PWRCTL_CTL		0xe8
> +
> +#define CORE_PWRCTL_BUS_OFF	0x01
> +#define CORE_PWRCTL_BUS_ON	(1 << 1)
> +#define CORE_PWRCTL_IO_LOW	(1 << 2)
> +#define CORE_PWRCTL_IO_HIGH	(1 << 3)
> +
> +#define CORE_PWRCTL_BUS_SUCCESS	0x01
> +#define CORE_PWRCTL_BUS_FAIL	(1 << 1)
> +#define CORE_PWRCTL_IO_SUCCESS	(1 << 2)
> +#define CORE_PWRCTL_IO_FAIL	(1 << 3)
> +
> +#define INT_MASK		0xf
> +
> +/* This structure keeps information per regulator */
> +struct sdhci_msm_reg_data {
> +	/* voltage regulator handle */

useless comment, please remove it.

> +	struct regulator *reg;
> +	/* regulator name */

useless comment

> +	const char *name;
> +	/* voltage level to be set */
> +	u32 low_vol_level;
> +	u32 high_vol_level;
> +	/* Load values for low power and high power mode */
> +	u32 lpm_uA;
> +	u32 hpm_uA;
> +
> +	/* is this regulator needs to be always on? */
> +	bool is_always_on;
> +	/* is low power mode setting required for this regulator? */
> +	bool lpm_sup;
> +};
> +
> +struct sdhci_msm_pltfm_data {
> +	u32 caps;				/* Supported UHS-I Modes */
> +	u32 caps2;				/* More capabilities */
> +	struct sdhci_msm_reg_data vdd_data;	/* VDD/VCC regulator info */
> +	struct sdhci_msm_reg_data vdd_io_data;	/* VDD IO regulator info */
> +};
> +
> +struct sdhci_msm_host {
> +	struct platform_device *pdev;
> +	void __iomem *core_mem;	/* MSM SDCC mapped address */
> +	int pwr_irq;		/* power irq */
> +	struct clk *clk;	/* main SD/MMC bus clock */
> +	struct clk *pclk;	/* SDHC peripheral bus clock */
> +	struct clk *bus_clk;	/* SDHC bus voter clock */
> +	struct sdhci_msm_pltfm_data pdata;
> +	struct mmc_host *mmc;
> +	struct sdhci_pltfm_data sdhci_msm_pdata;
> +};
> +
> +enum vdd_io_level {
> +	/* set vdd_io_data->low_vol_level */
> +	VDD_IO_LOW,
> +	/* set vdd_io_data->high_vol_level */
> +	VDD_IO_HIGH,
> +	/*
> +	 * set whatever there in voltage_level (third argument) of
> +	 * sdhci_msm_set_vdd_io_vol() function.
> +	 */
> +	VDD_IO_SET_LEVEL,
> +};
> +
> +#define MAX_PROP_SIZE 32
> +static int sdhci_msm_dt_parse_vreg_info(struct device *dev,
> +					struct sdhci_msm_reg_data *vreg,
> +					const char *vreg_name)
> +{
> +	int len, ret = 0;

ret is not used you can remove it and return 0 at the function end.

> +	const __be32 *prop;
> +	char prop_name[MAX_PROP_SIZE];
> +	struct device_node *np = dev->of_node;
> +
> +	snprintf(prop_name, MAX_PROP_SIZE, "%s-supply", vreg_name);
> +	if (!of_parse_phandle(np, prop_name, 0)) {
> +		dev_info(dev, "No vreg data found for %s\n", vreg_name);
> +		return -EINVAL;
> +	}
> +
> +	vreg->name = vreg_name;
> +
> +	snprintf(prop_name, MAX_PROP_SIZE, "qcom,%s-always-on", vreg_name);
> +	if (of_get_property(np, prop_name, NULL))
> +		vreg->is_always_on = true;
> +
> +	snprintf(prop_name, MAX_PROP_SIZE, "qcom,%s-lpm-sup", vreg_name);
> +	if (of_get_property(np, prop_name, NULL))
> +		vreg->lpm_sup = true;
> +
> +	snprintf(prop_name, MAX_PROP_SIZE, "qcom,%s-voltage-level", vreg_name);
> +	prop = of_get_property(np, prop_name, &len);
> +	if (!prop || (len != (2 * sizeof(__be32)))) {
> +		dev_warn(dev, "%s %s property\n",
> +			 prop ? "invalid format" : "no", prop_name);
> +	} else {
> +		vreg->low_vol_level = be32_to_cpup(&prop[0]);
> +		vreg->high_vol_level = be32_to_cpup(&prop[1]);
> +	}
> +
> +	snprintf(prop_name, MAX_PROP_SIZE, "qcom,%s-current-level", vreg_name);
> +	prop = of_get_property(np, prop_name, &len);
> +	if (!prop || (len != (2 * sizeof(__be32)))) {
> +		dev_warn(dev, "%s %s property\n",
> +			 prop ? "invalid format" : "no", prop_name);
> +	} else {
> +		vreg->lpm_uA = be32_to_cpup(&prop[0]);
> +		vreg->hpm_uA = be32_to_cpup(&prop[1]);
> +	}
> +
> +	dev_dbg(dev, "%s: %s%svol=[%d %d]uV, curr=[%d %d]uA\n",
> +		vreg->name, vreg->is_always_on ? "always_on, " : "",
> +		vreg->lpm_sup ? "lpm_sup, " : "", vreg->low_vol_level,
> +		vreg->high_vol_level, vreg->lpm_uA, vreg->hpm_uA);
> +
> +	return ret;
> +}
> +
> +/* Parse platform data */

parse devicetree data ?

> +static int sdhci_msm_populate_pdata(struct device *dev,
> +					struct sdhci_msm_pltfm_data *pdata)
> +{
> +	struct device_node *np = dev->of_node;
> +	int len, i;
> +
> +	if (sdhci_msm_dt_parse_vreg_info(dev, &pdata->vdd_data, "vdd")) {
> +		dev_err(dev, "failed parsing vdd data\n");
> +		return -EINVAL;
> +	}
> +	if (sdhci_msm_dt_parse_vreg_info(dev, &pdata->vdd_io_data, "vdd-io")) {
> +		dev_err(dev, "failed parsing vdd-io data\n");
> +		return -EINVAL;
> +	}
> +
> +	len = of_property_count_strings(np, "qcom,bus-speed-mode");
> +
> +	for (i = 0; i < len; i++) {
> +		const char *name = NULL;
> +
> +		of_property_read_string_index(np,
> +					"qcom,bus-speed-mode", i, &name);
> +		if (!name)
> +			continue;
> +
> +		if (!strncmp(name, "HS200_1p8v", sizeof("HS200_1p8v")))
> +			pdata->caps2 |= MMC_CAP2_HS200_1_8V_SDR;
> +		else if (!strncmp(name, "HS200_1p2v", sizeof("HS200_1p2v")))
> +			pdata->caps2 |= MMC_CAP2_HS200_1_2V_SDR;
> +		else if (!strncmp(name, "DDR_1p8v", sizeof("DDR_1p8v")))
> +			pdata->caps |= MMC_CAP_1_8V_DDR | MMC_CAP_UHS_DDR50;
> +		else if (!strncmp(name, "DDR_1p2v", sizeof("DDR_1p2v")))
> +			pdata->caps |= MMC_CAP_1_2V_DDR | MMC_CAP_UHS_DDR50;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Regulator utility functions */
> +static int sdhci_msm_vreg_init_reg(struct device *dev,
> +				   struct sdhci_msm_reg_data *vreg)
> +{
> +	int ret = 0;

could you remove ret variable, please.

> +	/* Get the regulator handle */

useless comment

> +	vreg->reg = devm_regulator_get(dev, vreg->name);
> +	if (IS_ERR(vreg->reg)) {
> +		ret = PTR_ERR(vreg->reg);
> +		dev_err(dev, "devm_regulator_get(%s) failed. ret=%d\n",
> +			vreg->name, ret);
> +		return ret;

just return PTR_ERR(vreg->reg)

> +	}
> +
> +	/* sanity check */
> +	if (!vreg->high_vol_level || !vreg->hpm_uA) {

if this is sanity check shouldn't you check low_vol_level and lpm_uA as
well?

> +		dev_err(dev, "%s invalid constraints specified\n", vreg->name);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sdhci_msm_vreg_enable(struct sdhci_msm_reg_data *vreg)
> +{
> +	int ret = 0;
> +
> +	/* Put regulator in HPM (high power mode) */
> +	ret = regulator_set_optimum_mode(vreg->reg, vreg->hpm_uA);
> +	if (ret < 0) {
> +		pr_err("regulator_set_optimum_mode(%s,uA_load=%d) fail (%d)\n",
> +			vreg->name, vreg->hpm_uA, ret);

use dev_err() instead.

> +		return ret;
> +	}
> +
> +	if (!regulator_is_enabled(vreg->reg)) {
> +		/* Set voltage level */
> +		ret = regulator_set_voltage(vreg->reg, vreg->high_vol_level,
> +						vreg->high_vol_level);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = regulator_enable(vreg->reg);
> +	if (ret) {
> +		pr_err("regulator_enable(%s) fail (%d)\n", vreg->name, ret);

use dev_err().

> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sdhci_msm_vreg_disable(struct sdhci_msm_reg_data *vreg)
> +{
> +	int ret = 0;

IMO no need to initialize ret variable?

> +
> +	if (!regulator_is_enabled(vreg->reg))
> +		return 0;
> +
> +	/* Never disable regulator marked as always_on */
> +	if (vreg->is_always_on) {
> +		if (vreg->lpm_sup) {
> +			/* Put always_on regulator in LPM (low power mode) */
> +			ret = regulator_set_optimum_mode(vreg->reg,
> +				vreg->lpm_uA);
> +			if (ret < 0)
> +				return ret;
> +		}
> +	} else {
> +		ret = regulator_disable(vreg->reg);
> +		if (ret) {
> +			pr_err("regulator_disable(%s) fail (%d)\n",
> +				vreg->name, ret);

dev_err(), please.

> +			return ret;
> +		}
> +
> +		ret = regulator_set_optimum_mode(vreg->reg, 0);
> +		if (ret < 0)
> +			return ret;
> +
> +		/* Set min. voltage level to 0 */
> +		ret = regulator_set_voltage(vreg->reg, 0, vreg->high_vol_level);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int sdhci_msm_setup_vreg(struct sdhci_msm_pltfm_data *pdata,
> +				bool enable, bool is_init)
> +{
> +	int ret = 0, i;

no need to initialize ret variable?

> +	struct sdhci_msm_reg_data *vreg_table[2];
> +
> +	vreg_table[0] = &pdata->vdd_data;
> +	vreg_table[1] = &pdata->vdd_io_data;
> +
> +	for (i = 0; i < ARRAY_SIZE(vreg_table); i++) {
> +		if (vreg_table[i]) {

could you invert the logic here:

		if (!vreg_table[i])
			continue;

by that way you will save one tab below.

> +			if (enable)
> +				ret = sdhci_msm_vreg_enable(vreg_table[i]);
> +			else
> +				ret = sdhci_msm_vreg_disable(vreg_table[i]);
> +			if (ret)
> +				return ret;
> +		}
> +	}

blank line ?

> +	return 0;
> +}
> +
> +/* This init function should be called only once for each SDHC slot */
> +static int sdhci_msm_vreg_init(struct device *dev,
> +				struct sdhci_msm_pltfm_data *pdata)
> +{
> +	struct sdhci_msm_reg_data *curr_vdd_reg = &pdata->vdd_data;
> +	struct sdhci_msm_reg_data *curr_vdd_io_reg = &pdata->vdd_io_data;
> +	int ret = 0;

no need to initialize ret variable.

> +
> +	ret = sdhci_msm_vreg_init_reg(dev, curr_vdd_reg);
> +	if (ret)
> +		return ret;
> +
> +	ret = sdhci_msm_vreg_init_reg(dev, curr_vdd_io_reg);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int sdhci_msm_set_vdd_io_vol(struct sdhci_msm_pltfm_data *pdata,
> +				    enum vdd_io_level level,
> +				    unsigned int voltage_level)
> +{
> +	int set_level;
> +	struct sdhci_msm_reg_data *vdd_io_reg = &pdata->vdd_io_data;
> +
> +	if (!regulator_is_enabled(vdd_io_reg->reg))
> +		return 0;
> +
> +	switch (level) {
> +	case VDD_IO_LOW:
> +		set_level = vdd_io_reg->low_vol_level;
> +		break;
> +	case VDD_IO_HIGH:
> +		set_level = vdd_io_reg->high_vol_level;
> +		break;
> +	case VDD_IO_SET_LEVEL:
> +		set_level = voltage_level;
> +		break;
> +	default:
> +		pr_err("invalid vdd_io level = %d", level);
> +		return -EINVAL;
> +	}

add blank line here, please.

> +	return regulator_set_voltage(vdd_io_reg->reg, set_level, set_level);
> +}
> +
> +static irqreturn_t sdhci_msm_pwr_irq(int irq, void *data)
> +{
> +	struct sdhci_msm_host *msm_host = (struct sdhci_msm_host *)data;
> +	u8 irq_status = 0;
> +	u8 irq_ack = 0;
> +	int ret = 0;

no need to initialize irq_status and ret, right?

> +
> +	irq_status = readb_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS);
> +	pr_debug("%s: Received IRQ(%d), status=0x%x\n",
> +		 mmc_hostname(msm_host->mmc), irq, irq_status);

dev_dbg() ?

> +
> +	/* Clear the interrupt */
> +	writeb_relaxed(irq_status, (msm_host->core_mem + CORE_PWRCTL_CLEAR));

why you use writeb here, but in .probe you use writel?

> +	/*
> +	 * SDHC has core_mem and hc_mem device memory and these memory
> +	 * addresses do not fall within 1KB region. Hence, any update to
> +	 * core_mem address space would require an mb() to ensure this gets
> +	 * completed before its next update to registers within hc_mem.
> +	 */
> +	mb();
> +
> +	/* Handle BUS ON/OFF */
> +	if (irq_status & (CORE_PWRCTL_BUS_ON | CORE_PWRCTL_BUS_OFF)) {
> +		bool flag = (irq_status & CORE_PWRCTL_BUS_ON) ? 1 : 0;
> +		ret = sdhci_msm_setup_vreg(&msm_host->pdata, flag, false);
> +		if (ret)
> +			irq_ack |= CORE_PWRCTL_BUS_FAIL;
> +		else
> +			irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> +	}
> +	/* Handle IO LOW/HIGH */
> +	if (irq_status & (CORE_PWRCTL_IO_LOW | CORE_PWRCTL_IO_HIGH)) {
> +		/* Switch voltage */
> +		int io_status = (irq_status & CORE_PWRCTL_IO_LOW) ?
> +		    VDD_IO_LOW : VDD_IO_HIGH;
> +		ret = sdhci_msm_set_vdd_io_vol(&msm_host->pdata, io_status, 0);
> +		if (ret)
> +			irq_ack |= CORE_PWRCTL_IO_FAIL;
> +		else
> +			irq_ack |= CORE_PWRCTL_IO_SUCCESS;
> +	}
> +
> +	/* ACK status to the core */
> +	writeb_relaxed(irq_ack, (msm_host->core_mem + CORE_PWRCTL_CTL));
> +	/*
> +	 * SDHC has core_mem and hc_mem device memory and these memory
> +	 * addresses do not fall within 1KB region. Hence, any update to
> +	 * core_mem address space would require an mb() to ensure this gets
> +	 * completed before its next update to registers within hc_mem.
> +	 */
> +	mb();
> +
> +	pr_debug("%s: Handled IRQ(%d), ret=%d, ack=0x%x\n",
> +		 mmc_hostname(msm_host->mmc), irq, ret, irq_ack);

dev_dbg() ?

> +	return IRQ_HANDLED;
> +}
> +
> +/* This function returns the max. current supported by VDD rail in mA */
> +static u32 sdhci_msm_get_vdd_max_current(struct sdhci_msm_host *host)
> +{
> +	return host->pdata.vdd_data.hpm_uA / 1000;
> +}
> +
> +static const struct of_device_id sdhci_msm_dt_match[] = {
> +	{.compatible = "qcom,sdhci-msm"},
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(of, sdhci_msm_dt_match);
> +
> +static int sdhci_msm_probe(struct platform_device *pdev)
> +{
> +	struct sdhci_host *host;
> +	struct sdhci_pltfm_host *pltfm_host;
> +	struct sdhci_msm_host *msm_host;
> +	struct resource *core_memres = NULL;
> +	int ret = 0, dead = 0;

no need to initialize ret and dead variables.

> +	struct pinctrl *pinctrl;
> +
> +	if (!pdev->dev.of_node) {
> +		dev_err(&pdev->dev, "No device tree data\n");
> +		return -ENOENT;
> +	}
> +
> +	msm_host = devm_kzalloc(&pdev->dev, sizeof(*msm_host), GFP_KERNEL);
> +	if (!msm_host)
> +		return -ENOMEM;
> +
> +	host = sdhci_pltfm_init(pdev, &msm_host->sdhci_msm_pdata, 0);
> +	if (IS_ERR(host)) {
> +		dev_err(mmc_dev(host->mmc), "sdhci_pltfm_init error\n");
> +		return PTR_ERR(host);
> +	}
> +
> +	pltfm_host = sdhci_priv(host);
> +	pltfm_host->priv = msm_host;
> +	msm_host->mmc = host->mmc;
> +	msm_host->pdev = pdev;
> +
> +	ret = mmc_of_parse(host->mmc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed parsing mmc device tree\n");
> +		goto pltfm_free;
> +	}
> +
> +	/* Extract platform data */

needless comment, again.

> +	ret = sdhci_msm_populate_pdata(&pdev->dev, &msm_host->pdata);
> +	if (ret) {
> +		dev_err(&pdev->dev, "DT parsing error\n");
> +		goto pltfm_free;
> +	}
> +
> +	/* Setup pins */
> +	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
> +	if (IS_ERR(pinctrl))
> +		dev_warn(&pdev->dev, "pins are not configured by the driver\n");
> +
> +	/* Setup SDCC bus voter clock. */
> +	msm_host->bus_clk = devm_clk_get(&pdev->dev, "bus");
> +	if (!IS_ERR(msm_host->bus_clk)) {
> +		/* Vote for max. clk rate for max. performance */
> +		ret = clk_set_rate(msm_host->bus_clk, INT_MAX);
> +		if (ret)
> +			goto pltfm_free;
> +		ret = clk_prepare_enable(msm_host->bus_clk);
> +		if (ret)
> +			goto pltfm_free;
> +	}
> +
> +	/* Setup main peripheral bus clock */
> +	msm_host->pclk = devm_clk_get(&pdev->dev, "iface");
> +	if (!IS_ERR(msm_host->pclk)) {
> +		ret = clk_prepare_enable(msm_host->pclk);
> +		if (ret) {
> +			dev_err(&pdev->dev,
> +				"Main peripheral clock setup failed (%d)\n",
> +				ret);
> +			goto bus_clk_disable;
> +		}
> +	}
> +
> +	/* Setup SDC MMC clock */
> +	msm_host->clk = devm_clk_get(&pdev->dev, "core");
> +	if (IS_ERR(msm_host->clk)) {
> +		ret = PTR_ERR(msm_host->clk);
> +		dev_err(&pdev->dev, "SDC MMC clock setup failed (%d)\n", ret);
> +		goto pclk_disable;
> +	}
> +
> +	ret = clk_prepare_enable(msm_host->clk);
> +	if (ret)
> +		goto pclk_disable;
> +
> +	/* Setup regulators */
> +	ret = sdhci_msm_vreg_init(&pdev->dev, &msm_host->pdata);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Regulator setup failed (%d)\n", ret);
> +		goto clk_disable;
> +	}
> +
> +	/* Reset the core and Enable SDHC mode */

this comment should go few lines below.

> +	core_memres = platform_get_resource_byname(pdev,
> +						   IORESOURCE_MEM, "core_mem");
> +	msm_host->core_mem = devm_ioremap_resource(&pdev->dev, core_memres);
> +
> +	if (IS_ERR(msm_host->core_mem)) {
> +		dev_err(&pdev->dev, "Failed to remap registers\n");
> +		ret = PTR_ERR(msm_host->core_mem);
> +		goto vreg_disable;
> +	}
> +
> +	/* Set SW_RST bit in POWER register (Offset 0x0) */

those comments are stupid, please remove them.

> +	writel_relaxed(CORE_SW_RST, msm_host->core_mem + CORE_POWER);
> +	/* Set HC_MODE_EN bit in HC_MODE register */
> +	writel_relaxed(HC_MODE_EN, (msm_host->core_mem + CORE_HC_MODE));
> +

are all interrupts disabled at this point?

> +	/*
> +	 * Following are the deviations from SDHC spec v3.0 -
> +	 * 1. Card detection is handled using separate GPIO.
> +	 * 2. Bus power control is handled by interacting with PMIC.
> +	 */
> +	host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> +
> +	/* Setup PWRCTL irq */
> +	msm_host->pwr_irq = platform_get_irq_byname(pdev, "pwr_irq");
> +	if (msm_host->pwr_irq < 0) {
> +		dev_err(&pdev->dev, "Failed to get pwr_irq by name (%d)\n",
> +			msm_host->pwr_irq);
> +		goto vreg_disable;
> +	}
> +	ret = devm_request_threaded_irq(&pdev->dev, msm_host->pwr_irq, NULL,
> +					sdhci_msm_pwr_irq, IRQF_ONESHOT,
> +					dev_name(&pdev->dev), host);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Request threaded irq(%d) failed (%d)\n",
> +			msm_host->pwr_irq, ret);
> +		goto vreg_disable;
> +	}
> +
> +	/* Enable pwr irq interrupts */
> +	writel_relaxed(INT_MASK, (msm_host->core_mem + CORE_PWRCTL_MASK));
> +
> +	/* Set host capabilities */

useless comment

> +	msm_host->mmc->caps |= msm_host->pdata.caps;
> +	msm_host->mmc->caps2 |= msm_host->pdata.caps2;
> +
> +	ret = sdhci_add_host(host);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Add host failed (%d)\n", ret);
> +		goto vreg_disable;
> +	}
> +
> +	/* Set core clk rate */

useless comment

> +	ret = clk_set_rate(msm_host->clk, host->max_clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "MClk rate set failed (%d)\n", ret);
> +		goto remove_host;
> +	}
> +
> +	host->mmc->max_current_180 = host->mmc->max_current_300 =
> +	host->mmc->max_current_330 = sdhci_msm_get_vdd_max_current(msm_host);
> +
> +	/* Successful initialization */

useless comment

> +	return 0;
> +
> +remove_host:
> +	dead = (readl_relaxed(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff);
> +	sdhci_remove_host(host, dead);
> +vreg_disable:
> +	if (!IS_ERR(msm_host->pdata.vdd_data.reg))
> +		sdhci_msm_vreg_disable(&msm_host->pdata.vdd_data);
> +	if (!IS_ERR(msm_host->pdata.vdd_io_data.reg))
> +		sdhci_msm_vreg_disable(&msm_host->pdata.vdd_io_data);
> +clk_disable:
> +	if (!IS_ERR(msm_host->clk))
> +		clk_disable_unprepare(msm_host->clk);
> +pclk_disable:
> +	if (!IS_ERR(msm_host->pclk))
> +		clk_disable_unprepare(msm_host->pclk);
> +bus_clk_disable:
> +	if (!IS_ERR(msm_host->bus_clk))
> +		clk_disable_unprepare(msm_host->bus_clk);
> +pltfm_free:
> +	sdhci_pltfm_free(pdev);
> +	return ret;
> +}
> +
> +static int sdhci_msm_remove(struct platform_device *pdev)
> +{
> +	struct sdhci_host *host = platform_get_drvdata(pdev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_msm_host *msm_host = pltfm_host->priv;
> +	int dead = (readl_relaxed(host->ioaddr + SDHCI_INT_STATUS) ==
> +		    0xffffffff);
> +
> +	sdhci_remove_host(host, dead);
> +	sdhci_pltfm_free(pdev);
> +	sdhci_msm_vreg_disable(&msm_host->pdata.vdd_data);
> +	sdhci_msm_vreg_disable(&msm_host->pdata.vdd_io_data);
> +	clk_disable_unprepare(msm_host->clk);
> +	clk_disable_unprepare(msm_host->pclk);
> +	if (!IS_ERR(msm_host->bus_clk))
> +		clk_disable_unprepare(msm_host->bus_clk);
> +	return 0;
> +}
> +
> +static struct platform_driver sdhci_msm_driver = {
> +	.probe = sdhci_msm_probe,
> +	.remove = sdhci_msm_remove,
> +	.driver = {
> +		   .name = "sdhci_msm",
> +		   .owner = THIS_MODULE,
> +		   .of_match_table = sdhci_msm_dt_match,
> +		   },

this bracket should be under ".driver".

> +};
> +
> +module_platform_driver(sdhci_msm_driver);
> +
> +MODULE_DESCRIPTION("Qualcomm Secure Digital Host Controller Interface driver");
> +MODULE_LICENSE("GPL v2");
> 

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