From fa64efa1f2a0672767ad0753a6e4bfa4bcc77b87 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <drzeus@drzeus.cx>
Date: Sun, 27 May 2007 14:22:37 +0200
Subject: mmc: enable/disable functions for SDIO

Like many other buses, the devices (functions) on the SDIO bus
must be enabled before they can be used. Add functions that allow
drivers to do so.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
---
 drivers/mmc/core/sdio_io.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

(limited to 'drivers/mmc/core')

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index 4ad06e57563..eb6c20935ce 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -11,6 +11,7 @@
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
+#include <linux/mmc/sdio.h>
 #include <linux/mmc/sdio_func.h>
 
 #include "sdio_ops.h"
@@ -47,6 +48,98 @@ void sdio_release_host(struct sdio_func *func)
 }
 EXPORT_SYMBOL_GPL(sdio_release_host);
 
+/**
+ *	sdio_enable_func - enables a SDIO function for usage
+ *	@func: SDIO function to enable
+ *
+ *	Powers up and activates a SDIO function so that register
+ *	access is possible.
+ */
+int sdio_enable_func(struct sdio_func *func)
+{
+	int ret;
+	unsigned char reg;
+	unsigned long timeout;
+
+	BUG_ON(!func);
+	BUG_ON(!func->card);
+
+	pr_debug("SDIO: Enabling device %s...\n", sdio_func_id(func));
+
+	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IOEx, 0, &reg);
+	if (ret)
+		goto err;
+
+	reg |= 1 << func->num;
+
+	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IOEx, reg, NULL);
+	if (ret)
+		goto err;
+
+	/*
+	 * FIXME: This should timeout based on information in the CIS,
+	 * but we don't have card to parse that yet.
+	 */
+	timeout = jiffies + HZ;
+
+	while (1) {
+		ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IORx, 0, &reg);
+		if (ret)
+			goto err;
+		if (reg & (1 << func->num))
+			break;
+		ret = -ETIME;
+		if (time_after(jiffies, timeout))
+			goto err;
+	}
+
+	pr_debug("SDIO: Enabled device %s\n", sdio_func_id(func));
+
+	return 0;
+
+err:
+	pr_debug("SDIO: Failed to enable device %s\n", sdio_func_id(func));
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sdio_enable_func);
+
+/**
+ *	sdio_disable_func - disable a SDIO function
+ *	@func: SDIO function to disable
+ *
+ *	Powers down and deactivates a SDIO function. Register access
+ *	to this function will fail until the function is reenabled.
+ */
+int sdio_disable_func(struct sdio_func *func)
+{
+	int ret;
+	unsigned char reg;
+
+	BUG_ON(!func);
+	BUG_ON(!func->card);
+
+	pr_debug("SDIO: Disabling device %s...\n", sdio_func_id(func));
+
+	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IOEx, 0, &reg);
+	if (ret)
+		goto err;
+
+	reg &= ~(1 << func->num);
+
+	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IOEx, reg, NULL);
+	if (ret)
+		goto err;
+
+	pr_debug("SDIO: Disabled device %s\n", sdio_func_id(func));
+
+	return 0;
+
+err:
+	pr_debug("SDIO: Failed to disable device %s\n", sdio_func_id(func));
+	return -EIO;
+}
+EXPORT_SYMBOL_GPL(sdio_disable_func);
+
 /**
  *	sdio_readb - read a single byte from a SDIO function
  *	@func: SDIO function to access
-- 
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