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path: root/drivers/mmc/core/cd-gpio.c
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Diffstat (limited to 'drivers/mmc/core/cd-gpio.c')
-rw-r--r--drivers/mmc/core/cd-gpio.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/mmc/core/cd-gpio.c b/drivers/mmc/core/cd-gpio.c
new file mode 100644
index 00000000000..082202ae4a0
--- /dev/null
+++ b/drivers/mmc/core/cd-gpio.c
@@ -0,0 +1,74 @@
+/*
+ * Generic GPIO card-detect helper
+ *
+ * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/mmc/host.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+struct mmc_cd_gpio {
+ unsigned int gpio;
+ char label[0];
+};
+
+static irqreturn_t mmc_cd_gpio_irqt(int irq, void *dev_id)
+{
+ /* Schedule a card detection after a debounce timeout */
+ mmc_detect_change(dev_id, msecs_to_jiffies(100));
+ return IRQ_HANDLED;
+}
+
+int mmc_cd_gpio_request(struct mmc_host *host, unsigned int gpio,
+ unsigned int irq, unsigned long flags)
+{
+ size_t len = strlen(dev_name(host->parent)) + 4;
+ struct mmc_cd_gpio *cd = kmalloc(sizeof(*cd) + len, GFP_KERNEL);
+ int ret;
+
+ if (!cd)
+ return -ENOMEM;
+
+ snprintf(cd->label, len, "%s cd", dev_name(host->parent));
+
+ ret = gpio_request_one(gpio, GPIOF_DIR_IN, cd->label);
+ if (ret < 0)
+ goto egpioreq;
+
+ ret = request_threaded_irq(irq, NULL, mmc_cd_gpio_irqt,
+ flags, cd->label, host);
+ if (ret < 0)
+ goto eirqreq;
+
+ cd->gpio = gpio;
+ host->hotplug.irq = irq;
+ host->hotplug.handler_priv = cd;
+
+ return 0;
+
+eirqreq:
+ gpio_free(gpio);
+egpioreq:
+ kfree(cd);
+ return ret;
+}
+EXPORT_SYMBOL(mmc_cd_gpio_request);
+
+void mmc_cd_gpio_free(struct mmc_host *host)
+{
+ struct mmc_cd_gpio *cd = host->hotplug.handler_priv;
+
+ free_irq(host->hotplug.irq, host);
+ gpio_free(cd->gpio);
+ kfree(cd);
+}
+EXPORT_SYMBOL(mmc_cd_gpio_free);