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mmc: dw_mmc: Handle wp-gpios from device tree

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On some SoCs (like exynos5250) you need to use an external GPIO for
write protect.  Add support for wp-gpios to the core dw_mmc driver
since it could be useful across multiple SoCs.

With this change I am able to make use of the write protect for the
external SD slot on exynos5250-snow.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Doug Anderson 2013-01-11 17:03:53 +00:00 committed by Chris Ball
parent 07b240411f
commit 55a6ceb2d5
1 changed files with 34 additions and 0 deletions
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34
drivers/mmc/host/dw_mmc.c
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@ -34,6 +34,7 @@
#include <linux/regulator/consumer.h>
#include <linux/workqueue.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include "dw_mmc.h"
@ -75,6 +76,7 @@ struct idmac_desc {
* @mmc: The mmc_host representing this slot.
* @host: The MMC controller this slot is using.
* @quirks: Slot-level quirks (DW_MCI_SLOT_QUIRK_XXX)
* @wp_gpio: If gpio_is_valid() we'll use this to read write protect.
* @ctype: Card type for this slot.
* @mrq: mmc_request currently being processed or waiting to be
* processed, or NULL when the slot is idle.
@ -90,6 +92,7 @@ struct dw_mci_slot {
struct dw_mci *host;
int quirks;
int wp_gpio;
u32 ctype;
@ -838,6 +841,8 @@ static int dw_mci_get_ro(struct mmc_host *mmc)
read_only = 0;
else if (brd->get_ro)
read_only = brd->get_ro(slot->id);
else if (gpio_is_valid(slot->wp_gpio))
read_only = gpio_get_value(slot->wp_gpio);
else
read_only =
mci_readl(slot->host, WRTPRT) & (1 << slot->id) ? 1 : 0;
@ -1832,6 +1837,29 @@ static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
" as 1\n");
return bus_wd;
}
/* find the write protect gpio for a given slot; or -1 if none specified */
static int dw_mci_of_get_wp_gpio(struct device *dev, u8 slot)
{
struct device_node *np = dw_mci_of_find_slot_node(dev, slot);
int gpio;
if (!np)
return -EINVAL;
gpio = of_get_named_gpio(np, "wp-gpios", 0);
/* Having a missing entry is valid; return silently */
if (!gpio_is_valid(gpio))
return -EINVAL;
if (devm_gpio_request(dev, gpio, "dw-mci-wp")) {
dev_warn(dev, "gpio [%d] request failed\n", gpio);
return -EINVAL;
}
return gpio;
}
#else /* CONFIG_OF */
static int dw_mci_of_get_slot_quirks(struct device *dev, u8 slot)
{
@ -1845,6 +1873,10 @@ static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
{
return NULL;
}
static int dw_mci_of_get_wp_gpio(struct device *dev, u8 slot)
{
return -EINVAL;
}
#endif /* CONFIG_OF */
static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
@ -1962,6 +1994,8 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
else
clear_bit(DW_MMC_CARD_PRESENT, &slot->flags);
slot->wp_gpio = dw_mci_of_get_wp_gpio(host->dev, slot->id);
mmc_add_host(mmc);
#if defined(CONFIG_DEBUG_FS)