The MMC subsystem uses a discoverable bus which sometimes means the
power sequences to enable power to the card, is far too complex to be
handled through the regular ->set_ios() callback.

To adress these scenarios, we try to fetch a pwrseq method while
parsing the common MMC DT bindings. If a such method is found we select
the corresponding state for it from mmc_power_up|off().

Signed-off-by: Ulf Hansson <ulf.hans...@linaro.org>
---
 drivers/mmc/core/core.c  |    7 +++++++
 drivers/mmc/core/host.c  |    5 +++++
 include/linux/mmc/host.h |    3 +++
 3 files changed, 15 insertions(+)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 7dc0c85..46558b5 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -29,6 +29,7 @@
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/pwrseq.h>
 
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
@@ -1533,6 +1534,9 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
 
        mmc_host_clk_hold(host);
 
+       if (!IS_ERR(host->pwrseq))
+               pwrseq_select_state(host->pwrseq, PWRSEQ_POWER_ON);
+
        host->ios.vdd = fls(ocr) - 1;
        if (mmc_host_is_spi(host))
                host->ios.chip_select = MMC_CS_HIGH;
@@ -1591,6 +1595,9 @@ void mmc_power_off(struct mmc_host *host)
        host->ios.timing = MMC_TIMING_LEGACY;
        mmc_set_ios(host);
 
+       if (!IS_ERR(host->pwrseq))
+               pwrseq_select_state(host->pwrseq, PWRSEQ_POWER_OFF);
+
        /*
         * Some configurations, such as the 802.11 SDIO card in the OLPC
         * XO-1.5, require a short delay after poweroff before the card
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 95cceae..fdf8596 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -22,6 +22,7 @@
 #include <linux/leds.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
+#include <linux/pwrseq.h>
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
@@ -317,6 +318,10 @@ int mmc_of_parse(struct mmc_host *host)
        if (!host->parent || !host->parent->of_node)
                return 0;
 
+       host->pwrseq = devm_pwrseq_get_optional(host->parent);
+       if (IS_ERR(host->pwrseq))
+               return PTR_ERR(host->pwrseq);
+
        np = host->parent->of_node;
 
        /* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 7960424..306b78c 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -195,9 +195,12 @@ struct mmc_supply {
        struct regulator *vqmmc;        /* Optional Vccq supply */
 };
 
+struct pwrseq;
+
 struct mmc_host {
        struct device           *parent;
        struct device           class_dev;
+       struct pwrseq           *pwrseq;
        int                     index;
        const struct mmc_host_ops *ops;
        unsigned int            f_min;
-- 
1.7.9.5

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