Commit 3aa8793f authored by Ulf Hansson's avatar Ulf Hansson
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mmc: core: Initial support for MMC power sequences 



System on chip designs may specify a specific MMC power sequence. To
successfully detect an (e)MMC/SD/SDIO card, that power sequence must
be followed while initializing the card.

To be able to handle these SOC specific power sequences, let's add a
MMC power sequence interface. It provides the following functions to
help the mmc core to deal with these power sequences.

mmc_pwrseq_alloc() - Invoked from mmc_of_parse(), to initialize data.
mmc_pwrseq_pre_power_on()- Invoked in the beginning of mmc_power_up().
mmc_pwrseq_post_power_on()- Invoked at the end in mmc_power_up().
mmc_pwrseq_power_off()- Invoked from mmc_power_off().
mmc_pwrseq_free() - Invoked from mmc_free_host(), to free data.

Each MMC power sequence provider will be responsible to implement a set
of callbacks. These callbacks mirrors the functions above.

This patch adds the skeleton, following patches will extend the core of
the MMC power sequence and add support for a specific simple MMC power
sequence.

Do note, since the mmc_pwrseq_alloc() is invoked from mmc_of_parse(),
host drivers needs to make use of this API to enable the support for
MMC power sequences. Moreover the MMC power sequence support depends on
CONFIG_OF.

Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Tested-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
parent c25d9e1b

drivers/mmc/core/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -8,5 +8,5 @@ mmc_core-y := core.o bus.o host.o \ 
				   sdio.o sdio_ops.o sdio_bus.o \

				   sdio_cis.o sdio_io.o sdio_irq.o \

				   quirks.o slot-gpio.o



mmc_core-$(CONFIG_OF)		+= pwrseq.o

mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o

drivers/mmc/core/core.c

+7 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ 
#include "bus.h"

#include "host.h"

#include "sdio_bus.h"

#include "pwrseq.h"



#include "mmc_ops.h"

#include "sd_ops.h"
@@ -1615,6 +1616,8 @@ void mmc_power_up(struct mmc_host *host, u32 ocr) 


	mmc_host_clk_hold(host);



	mmc_pwrseq_pre_power_on(host);



	host->ios.vdd = fls(ocr) - 1;

	host->ios.power_mode = MMC_POWER_UP;

	/* Set initial state and call mmc_set_ios */
@@ -1645,6 +1648,8 @@ void mmc_power_up(struct mmc_host *host, u32 ocr) 
	 */

	mmc_delay(10);



	mmc_pwrseq_post_power_on(host);



	mmc_host_clk_release(host);

}
@@ -1655,6 +1660,8 @@ void mmc_power_off(struct mmc_host *host) 


	mmc_host_clk_hold(host);



	mmc_pwrseq_power_off(host);



	host->ios.clock = 0;

	host->ios.vdd = 0;

drivers/mmc/core/host.c

+3 −1
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include "core.h"

#include "host.h"

#include "slot-gpio.h"

#include "pwrseq.h"



#define cls_dev_to_mmc_host(d)	container_of(d, struct mmc_host, class_dev)
@@ -448,7 +449,7 @@ int mmc_of_parse(struct mmc_host *host) 
		host->dsr_req = 0;

	}



	return 0;

	return mmc_pwrseq_alloc(host);

}



EXPORT_SYMBOL(mmc_of_parse);
@@ -588,6 +589,7 @@ EXPORT_SYMBOL(mmc_remove_host); 
 */

void mmc_free_host(struct mmc_host *host)

{

	mmc_pwrseq_free(host);

	put_device(&host->class_dev);

}

drivers/mmc/core/pwrseq.c

0 → 100644
+50 −0
Original line number Diff line number Diff line 
/*

 *  Copyright (C) 2014 Linaro Ltd

 *

 * Author: Ulf Hansson <ulf.hansson@linaro.org>

 *

 * License terms: GNU General Public License (GPL) version 2

 *

 *  MMC power sequence management

 */

#include <linux/mmc/host.h>



#include "pwrseq.h"





int mmc_pwrseq_alloc(struct mmc_host *host)

{

	return 0;

}



void mmc_pwrseq_pre_power_on(struct mmc_host *host)

{

	struct mmc_pwrseq *pwrseq = host->pwrseq;



	if (pwrseq && pwrseq->ops && pwrseq->ops->pre_power_on)

		pwrseq->ops->pre_power_on(host);

}



void mmc_pwrseq_post_power_on(struct mmc_host *host)

{

	struct mmc_pwrseq *pwrseq = host->pwrseq;



	if (pwrseq && pwrseq->ops && pwrseq->ops->post_power_on)

		pwrseq->ops->post_power_on(host);

}



void mmc_pwrseq_power_off(struct mmc_host *host)

{

	struct mmc_pwrseq *pwrseq = host->pwrseq;



	if (pwrseq && pwrseq->ops && pwrseq->ops->power_off)

		pwrseq->ops->power_off(host);

}



void mmc_pwrseq_free(struct mmc_host *host)

{

	struct mmc_pwrseq *pwrseq = host->pwrseq;



	if (pwrseq && pwrseq->ops && pwrseq->ops->free)

		pwrseq->ops->free(host);

}

drivers/mmc/core/pwrseq.h

0 → 100644
+40 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2014 Linaro Ltd

 *

 * Author: Ulf Hansson <ulf.hansson@linaro.org>

 *

 * License terms: GNU General Public License (GPL) version 2

 */

#ifndef _MMC_CORE_PWRSEQ_H

#define _MMC_CORE_PWRSEQ_H



struct mmc_pwrseq_ops {

	void (*pre_power_on)(struct mmc_host *host);

	void (*post_power_on)(struct mmc_host *host);

	void (*power_off)(struct mmc_host *host);

	void (*free)(struct mmc_host *host);

};



struct mmc_pwrseq {

	struct mmc_pwrseq_ops *ops;

};



#ifdef CONFIG_OF



int mmc_pwrseq_alloc(struct mmc_host *host);

void mmc_pwrseq_pre_power_on(struct mmc_host *host);

void mmc_pwrseq_post_power_on(struct mmc_host *host);

void mmc_pwrseq_power_off(struct mmc_host *host);

void mmc_pwrseq_free(struct mmc_host *host);



#else



static inline int mmc_pwrseq_alloc(struct mmc_host *host) { return 0; }

static inline void mmc_pwrseq_pre_power_on(struct mmc_host *host) {}

static inline void mmc_pwrseq_post_power_on(struct mmc_host *host) {}

static inline void mmc_pwrseq_power_off(struct mmc_host *host) {}

static inline void mmc_pwrseq_free(struct mmc_host *host) {}



#endif



#endif

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