mmc: dw_mmc: Handle wp-gpios from device tree
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>
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 90f7d99..df62079 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -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 @@
* @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 *host;
int quirks;
+ int wp_gpio;
u32 ctype;
@@ -838,6 +841,8 @@
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 @@
" 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 @@
{
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 @@
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)