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Subject[PATCH 5/6] atmel-mci: Power control option for each MMC Slot
Date
Add support to the atmel-mci driver for a VCC pin in order to conserve power by removing power from an MMC Slot.

Signed-off-by: Rob Emanuele <rob@emanuele.us>
---
drivers/mmc/host/atmel-mci.c | 33 ++++++++++++++++++++-------------
include/linux/atmel-mci.h | 2 ++
2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 601dae7..63cd5c7 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -214,6 +214,8 @@ struct atmel_mci_slot {
int detect_pin;
int wp_pin;
bool detect_is_active_high;
+ int vcc_pin;
+ bool vcc_active_low;

struct timer_list detect_timer;
};
@@ -932,23 +934,19 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
}

switch (ios->power_mode) {
+ case MMC_POWER_OFF:
+ if (gpio_is_valid(slot->vcc_pin))
+ gpio_set_value(slot->vcc_pin, slot->vcc_active_low);
+ break;
case MMC_POWER_UP:
+ if (gpio_is_valid(slot->vcc_pin))
+ gpio_set_value(slot->vcc_pin, !slot->vcc_active_low);
set_bit(ATMCI_CARD_NEED_INIT, &slot->flags);
break;
- default:
- /*
- * TODO: None of the currently available AVR32-based
- * boards allow MMC power to be turned off. Implement
- * power control when this can be tested properly.
- *
- * We also need to hook this into the clock management
- * somehow so that newly inserted cards aren't
- * subjected to a fast clock before we have a chance
- * to figure out what the maximum rate is. Currently,
- * there's no way to avoid this, and there never will
- * be for boards that don't support power control.
- */
+ case MMC_POWER_ON:
break;
+ default:
+ WARN_ON(1);
}
}

@@ -1507,6 +1505,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
slot->detect_pin = slot_data->detect_pin;
slot->wp_pin = slot_data->wp_pin;
slot->detect_is_active_high = slot_data->detect_is_active_high;
+ slot->vcc_pin = slot_data->vcc_pin;
+ slot->vcc_active_low = slot_data->vcc_active_low;
slot->sdc_reg = sdc_reg;

mmc->ops = &atmci_ops;
@@ -1544,6 +1544,13 @@ static int __init atmci_init_slot(struct atmel_mci *host,
}
}

+ if (gpio_is_valid(slot->vcc_pin)) {
+ if (gpio_request(slot->vcc_pin, "mmc_pow")) {
+ dev_dbg(&mmc->class_dev, "no power pin available\n");
+ slot->vcc_pin = -EBUSY;
+ }
+ }
+
host->slot[id] = slot;
mmc_add_host(mmc);

diff --git a/include/linux/atmel-mci.h b/include/linux/atmel-mci.h
index 57b1846..7c15a7c 100644
--- a/include/linux/atmel-mci.h
+++ b/include/linux/atmel-mci.h
@@ -26,6 +26,8 @@ struct mci_slot_pdata {
int detect_pin;
int wp_pin;
bool detect_is_active_high;
+ int vcc_pin;
+ unsigned vcc_active_low:1;
};

/**
--
1.6.0.4


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