wl12xx: add platform data passing support

Add a simple mechanism to pass platform data to the
SDIO instances of wl12xx.

This way there is no confusion over who owns the 'embedded data',
typechecking is preserved, and no possibility for the wrong driver to
pick up the data.

Originally proposed by Russell King.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/Makefile

@@ -50,5 +50,7 @@ obj-$(CONFIG_ATH_COMMON)	+= ath/
 obj-$(CONFIG_MAC80211_HWSIM)	+= mac80211_hwsim.o
 
 obj-$(CONFIG_WL12XX)	+= wl12xx/
+# small builtin driver bit
+obj-$(CONFIG_WL12XX_PLATFORM_DATA)	+= wl12xx/wl12xx_platform_data.o
 
 obj-$(CONFIG_IWM)	+= iwmc3200wifi/

drivers/net/wireless/wl12xx/Kconfig

@@ -74,4 +74,7 @@ config WL1271_SDIO
 	  If you choose to build a module, it'll be called
 	  wl1271_sdio. Say N if unsure.
 
-
+config WL12XX_PLATFORM_DATA
+	bool
+	depends on WL1271_SDIO != n
+	default y

drivers/net/wireless/wl12xx/wl12xx_platform_data.c

@@ -0,0 +1,28 @@
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/wl12xx.h>
+
+static const struct wl12xx_platform_data *platform_data;
+
+int __init wl12xx_set_platform_data(const struct wl12xx_platform_data *data)
+{
+	if (platform_data)
+		return -EBUSY;
+	if (!data)
+		return -EINVAL;
+
+	platform_data = kmemdup(data, sizeof(*data), GFP_KERNEL);
+	if (!platform_data)
+		return -ENOMEM;
+
+	return 0;
+}
+
+const struct wl12xx_platform_data *wl12xx_get_platform_data(void)
+{
+	if (!platform_data)
+		return ERR_PTR(-ENODEV);
+
+	return platform_data;
+}
+EXPORT_SYMBOL(wl12xx_get_platform_data);

include/linux/wl12xx.h

@@ -31,4 +31,7 @@ struct wl12xx_platform_data {
 	bool use_eeprom;
 };
 
+int wl12xx_set_platform_data(const struct wl12xx_platform_data *data);
+const struct wl12xx_platform_data *wl12xx_get_platform_data(void);
+
 #endif