summaryrefslogtreecommitdiff
path: root/drivers/mmc/core/slot-gpio.c
diff options
context:
space:
mode:
authorGuennadi Liakhovetski <g.liakhovetski@gmx.de>2012-04-30 23:31:57 +0200
committerChris Ball <cjb@laptop.org>2012-07-10 23:04:04 -0400
commitfd0ea65d3e675e479e022b6cfc9ebe1864c76afc (patch)
tree8869d7965ccb05b9ca635d21c983d84a552ee21e /drivers/mmc/core/slot-gpio.c
parent0f506a96693d8ad4aeccbd98dbd54a3c7357cfa8 (diff)
mmc: extend and rename cd-gpio helpers to handle more slot GPIO functions
GPIOs can be used in MMC/SD-card slots not only for hotplug detection, but also to implement the write-protection pin. Rename cd-gpio helpers to slot-gpio to make addition of further slot GPIO functions possible. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'drivers/mmc/core/slot-gpio.c')
-rw-r--r--drivers/mmc/core/slot-gpio.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
new file mode 100644
index 000000000000..979671053436
--- /dev/null
+++ b/drivers/mmc/core/slot-gpio.c
@@ -0,0 +1,83 @@
+/*
+ * 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/mmc/slot-gpio.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+struct mmc_gpio {
+ unsigned int cd_gpio;
+ char cd_label[0];
+};
+
+static irqreturn_t mmc_gpio_cd_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_gpio_request_cd(struct mmc_host *host, unsigned int gpio)
+{
+ size_t len = strlen(dev_name(host->parent)) + 4;
+ struct mmc_gpio *ctx;
+ int irq = gpio_to_irq(gpio);
+ int ret;
+
+ if (irq < 0)
+ return irq;
+
+ ctx = kmalloc(sizeof(*ctx) + len, GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent));
+
+ ret = gpio_request_one(gpio, GPIOF_DIR_IN, ctx->cd_label);
+ if (ret < 0)
+ goto egpioreq;
+
+ ret = request_threaded_irq(irq, NULL, mmc_gpio_cd_irqt,
+ IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ ctx->cd_label, host);
+ if (ret < 0)
+ goto eirqreq;
+
+ ctx->cd_gpio = gpio;
+ host->hotplug.irq = irq;
+ host->hotplug.handler_priv = ctx;
+
+ return 0;
+
+eirqreq:
+ gpio_free(gpio);
+egpioreq:
+ kfree(ctx);
+ return ret;
+}
+EXPORT_SYMBOL(mmc_gpio_request_cd);
+
+void mmc_gpio_free_cd(struct mmc_host *host)
+{
+ struct mmc_gpio *ctx = host->hotplug.handler_priv;
+
+ if (!ctx)
+ return;
+
+ free_irq(host->hotplug.irq, host);
+ gpio_free(ctx->cd_gpio);
+ kfree(ctx);
+}
+EXPORT_SYMBOL(mmc_gpio_free_cd);