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mmc: core: Initial support for MMC power sequences

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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: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
This commit is contained in:
Ulf Hansson 2014-11-28 14:38:36 +01:00
parent c25d9e1bda
commit 3aa8793f75
6 changed files with 103 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/mmc/core/Makefile
View File

@ -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

7
drivers/mmc/core/core.c
View File

@ -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;

4
drivers/mmc/core/host.c
View File

@ -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);
}

50
drivers/mmc/core/pwrseq.c Normal file
View File

@ -0,0 +1,50 @@
/*
* 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);
}

40
drivers/mmc/core/pwrseq.h Normal file
View File

@ -0,0 +1,40 @@
/*
* 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

2
include/linux/mmc/host.h
View File

@ -195,6 +195,7 @@ struct mmc_context_info {
};
struct regulator;
struct mmc_pwrseq;
struct mmc_supply {
struct regulator *vmmc; /* Card power supply */
@ -206,6 +207,7 @@ struct mmc_host {
struct device class_dev;
int index;
const struct mmc_host_ops *ops;
struct mmc_pwrseq *pwrseq;
unsigned int f_min;
unsigned int f_max;
unsigned int f_init;