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Commit 6c56e7a0 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Chris Ball
Browse files

mmc: provide a standard MMC device-tree binding parser centrally 



MMC defines a number of standard DT bindings. Having each driver parse
them individually adds code redundancy and is error prone. Provide a
standard function to unify the parsing. After all drivers are converted
to using it instead of their own parsers, this function can be integrated
into mmc_alloc_host().

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 6da15e96

drivers/mmc/core/host.c

+110 −0
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ 
#include <linux/device.h>

#include <linux/err.h>

#include <linux/idr.h>

#include <linux/of.h>

#include <linux/of_gpio.h>

#include <linux/pagemap.h>

#include <linux/export.h>

#include <linux/leds.h>
@@ -23,6 +25,7 @@ 


#include <linux/mmc/host.h>

#include <linux/mmc/card.h>

#include <linux/mmc/slot-gpio.h>



#include "core.h"

#include "host.h"
@@ -294,6 +297,113 @@ static inline void mmc_host_clk_sysfs_init(struct mmc_host *host) 


#endif



/**

 *	mmc_of_parse() - parse host's device-tree node

 *	@host: host whose node should be parsed.

 *

 * To keep the rest of the MMC subsystem unaware of whether DT has been

 * used to to instantiate and configure this host instance or not, we

 * parse the properties and set respective generic mmc-host flags and

 * parameters.

 */

void mmc_of_parse(struct mmc_host *host)

{

	struct device_node *np;

	u32 bus_width;

	bool explicit_inv_wp, gpio_inv_wp = false;

	enum of_gpio_flags flags;

	int len, ret, gpio;



	if (!host->parent || !host->parent->of_node)

		return;



	np = host->parent->of_node;



	/* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */

	if (of_property_read_u32(np, "bus-width", &bus_width) < 0) {

		dev_dbg(host->parent,

			"\"bus-width\" property is missing, assuming 1 bit.\n");

		bus_width = 1;

	}



	switch (bus_width) {

	case 8:

		host->caps |= MMC_CAP_8_BIT_DATA;

		/* Hosts capable of 8-bit transfers can also do 4 bits */

	case 4:

		host->caps |= MMC_CAP_4_BIT_DATA;

		break;

	case 1:

		break;

	default:

		dev_err(host->parent,

			"Invalid \"bus-width\" value %ud!\n", bus_width);

	}



	/* f_max is obtained from the optional "max-frequency" property */

	of_property_read_u32(np, "max-frequency", &host->f_max);



	/*

	 * Configure CD and WP pins. They are both by default active low to

	 * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the

	 * mmc-gpio helpers are used to attach, configure and use them. If

	 * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH

	 * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the

	 * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability

	 * is set. If the "non-removable" property is found, the

	 * MMC_CAP_NONREMOVABLE capability is set and no card-detection

	 * configuration is performed.

	 */



	/* Parse Card Detection */

	if (of_find_property(np, "non-removable", &len)) {

		host->caps |= MMC_CAP_NONREMOVABLE;

	} else {

		bool explicit_inv_cd, gpio_inv_cd = false;



		explicit_inv_cd = of_property_read_bool(np, "cd-inverted");



		if (of_find_property(np, "broken-cd", &len))

			host->caps |= MMC_CAP_NEEDS_POLL;



		gpio = of_get_named_gpio_flags(np, "cd-gpios", 0, &flags);

		if (gpio_is_valid(gpio)) {

			if (!(flags & OF_GPIO_ACTIVE_LOW))

				gpio_inv_cd = true;



			ret = mmc_gpio_request_cd(host, gpio);

			if (ret < 0)

				dev_err(host->parent,

					"Failed to request CD GPIO #%d: %d!\n",

					gpio, ret);

			else

				dev_info(host->parent, "Got CD GPIO #%d.\n",

					 gpio);

		}



		if (explicit_inv_cd ^ gpio_inv_cd)

			host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;

	}



	/* Parse Write Protection */

	explicit_inv_wp = of_property_read_bool(np, "wp-inverted");



	gpio = of_get_named_gpio_flags(np, "wp-gpios", 0, &flags);

	if (gpio_is_valid(gpio)) {

		if (!(flags & OF_GPIO_ACTIVE_LOW))

			gpio_inv_wp = true;



		ret = mmc_gpio_request_ro(host, gpio);

		if (ret < 0)

			dev_err(host->parent,

				"Failed to request WP GPIO: %d!\n", ret);

	}

	if (explicit_inv_wp ^ gpio_inv_wp)

		host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;

}



EXPORT_SYMBOL(mmc_of_parse);



/**

 *	mmc_alloc_host - initialise the per-host structure.

 *	@extra: sizeof private data structure

include/linux/mmc/host.h

+1 −0
Original line number Diff line number Diff line
@@ -368,6 +368,7 @@ extern struct mmc_host *mmc_alloc_host(int extra, struct device *); 
extern int mmc_add_host(struct mmc_host *);

extern void mmc_remove_host(struct mmc_host *);

extern void mmc_free_host(struct mmc_host *);

void mmc_of_parse(struct mmc_host *host);



static inline void *mmc_priv(struct mmc_host *host)

{