[PATCH 1/2] GTA02-specific rfkill framework for WLAN

[Werner Almesberger]

The patch extends the GTA02 WLAN power management platform device to
register an rfkill handler and to provide a "dock" to which the AR6k
driver can connect to pick up rfkill state and transitions.

We need this indirection because suspend/resume causes removal of the
driver, which therefore cannot retain rfkill state on its own.

Signed-off-by: Werner Almesberger <werner at openmoko.org>

---

Index: ktrack/arch/arm/mach-s3c2410/include/mach/gta02-pm-wlan.h
===================================================================
--- ktrack.orig/arch/arm/mach-s3c2410/include/mach/gta02-pm-wlan.h	2009-01-15 15:42:47.000000000 -0200
+++ ktrack/arch/arm/mach-s3c2410/include/mach/gta02-pm-wlan.h	2009-01-15 15:52:36.000000000 -0200
@@ -1 +1,10 @@
+#ifndef __MACH_GTA02_PM_WLAN_H
+#define __MACH_GTA02_PM_WLAN_H
+
 void gta02_wlan_power(int on);
+int gta02_wlan_query_rfkill_lock(void);
+void gta02_wlan_query_rfkill_unlock(void);
+void gta02_wlan_set_rfkill_cb(int (*cb)(void *user, int on), void *user);
+void gta02_wlan_clear_rfkill_cb(void);
+
+#endif /* __MACH_GTA02_PM_WLAN_H */
Index: ktrack/arch/arm/plat-s3c24xx/gta02_pm_wlan.c
===================================================================
--- ktrack.orig/arch/arm/plat-s3c24xx/gta02_pm_wlan.c	2009-01-15 15:42:47.000000000 -0200
+++ ktrack/arch/arm/plat-s3c24xx/gta02_pm_wlan.c	2009-01-15 23:04:14.000000000 -0200
@@ -1,7 +1,7 @@
 /*
  * GTA02 WLAN power management
  *
- * (C) 2008 by Openmoko Inc.
+ * (C) 2008, 2009 by Openmoko Inc.
  * Author: Andy Green <andy at openmoko.com>
  * All rights reserved.
  *
@@ -27,6 +27,10 @@
 #include <mach/regs-gpioj.h>
 
 #include <linux/delay.h>
+#include <linux/rfkill.h>
+
+
+/* ----- Module hardware reset ("power") ----------------------------------- */
 
 
 static void __gta02_wlan_power(int on)
@@ -109,10 +113,94 @@
 	.attrs	= gta02_wlan_sysfs_entries,
 };
 
+
+/* ----- rfkill ------------------------------------------------------------ */
+
+/*
+ * S3C MCI handles suspend/resume through device removal/insertion. In order to
+ * preserve rfkill state, as required in clause 7 of section 3.1 in rfkill.txt,
+ * we therefore need to maintain rfkill state outside the driver.
+ *
+ * This platform driver is as good a place as any other.
+ */
+
+static int (*gta02_wlan_rfkill_cb)(void *user, int on);
+static void *gta02_wlan_rfkill_user;
+static DEFINE_MUTEX(gta02_wlan_rfkill_lock);
+static int gta02_wlan_rfkill_on;
+
+
+/*
+ * gta02_wlan_query_rfkill_lock is used to obtain the rfkill state before the
+ * driver is ready to process rfkill callbacks. To prevent the state from
+ * changing until the driver has completed its initialization, we grab and hold
+ * the rfkill lock.
+ *
+ * A call to gta02_wlan_query_rfkill_lock must be followed by either
+ * - a call to gta02_wlan_set_rfkill_cb, to complete the setup, or
+ * - a call to gta02_wlan_query_rfkill_unlock to abort the setup process.
+ */
+
+int gta02_wlan_query_rfkill_lock(void)
+{
+	mutex_lock(&gta02_wlan_rfkill_lock);
+	return gta02_wlan_rfkill_on;
+}
+EXPORT_SYMBOL_GPL(gta02_wlan_query_rfkill_lock);
+
+void gta02_wlan_query_rfkill_unlock(void)
+{
+	mutex_unlock(&gta02_wlan_rfkill_lock);
+}
+EXPORT_SYMBOL_GPL(gta02_wlan_query_rfkill_unlock);
+
+
+void gta02_wlan_set_rfkill_cb(int (*cb)(void *user, int on), void *user)
+{
+	BUG_ON(!mutex_is_locked(&gta02_wlan_rfkill_lock));
+	BUG_ON(gta02_wlan_rfkill_cb);
+	gta02_wlan_rfkill_cb = cb;
+	gta02_wlan_rfkill_user = user;
+	mutex_unlock(&gta02_wlan_rfkill_lock);
+}
+EXPORT_SYMBOL_GPL(gta02_wlan_set_rfkill_cb);
+
+void gta02_wlan_clear_rfkill_cb(void)
+{
+	mutex_lock(&gta02_wlan_rfkill_lock);
+	BUG_ON(!gta02_wlan_rfkill_cb);
+	gta02_wlan_rfkill_cb = NULL;
+	mutex_unlock(&gta02_wlan_rfkill_lock);
+}
+EXPORT_SYMBOL_GPL(gta02_wlan_clear_rfkill_cb);
+
+static int gta02_wlan_toggle_radio(void *data, enum rfkill_state state)
+{
+	struct device *dev = data;
+	int on = state == RFKILL_STATE_UNBLOCKED;
+	int res = 0;
+
+	dev_dbg(dev, "gta02_wlan_toggle_radio: state %d (%p)\n",
+	    state, gta02_wlan_rfkill_cb);
+	mutex_lock(&gta02_wlan_rfkill_lock);
+	if (gta02_wlan_rfkill_cb)
+		res = gta02_wlan_rfkill_cb(gta02_wlan_rfkill_user, on);
+	if (!res)
+		gta02_wlan_rfkill_on = on;
+	mutex_unlock(&gta02_wlan_rfkill_lock);
+	return res;
+}
+
+
+/* ----- Initialization/removal -------------------------------------------- */
+
+
 static int __init gta02_wlan_probe(struct platform_device *pdev)
 {
 	/* default-on for now */
 	const int default_state = 1;
+	struct rfkill *rfkill;
+	int error;
 
 	if (!machine_is_neo1973_gta02())
 		return -EINVAL;
@@ -121,13 +209,45 @@
 
 	s3c2410_gpio_cfgpin(GTA02_CHIP_PWD, S3C2410_GPIO_OUTPUT);
 	s3c2410_gpio_cfgpin(GTA02_GPIO_nWLAN_RESET, S3C2410_GPIO_OUTPUT);
-	gta02_wlan_power(default_state);
+	gta02_wlan_power(1);
+
+	rfkill = rfkill_allocate(&pdev->dev, RFKILL_TYPE_WLAN);
+	rfkill->name = "ar6000";
+	rfkill->data = &pdev->dev;
+	rfkill->state = default_state ? RFKILL_STATE_ON : RFKILL_STATE_OFF;
+	/*
+	 * If the WLAN driver somehow managed to get activated before we're
+	 * ready, the driver is now in an unknown state, which isn't something
+	 * we're prepared to handle. This can't happen, so just fail hard.
+	 */
+	BUG_ON(gta02_wlan_rfkill_cb);
+	gta02_wlan_rfkill_on = default_state;
+	rfkill->toggle_radio = gta02_wlan_toggle_radio;
+
+	error = rfkill_register(rfkill);
+	if (error) {
+		rfkill_free(rfkill);
+		return error;
+	}
+
+	error = sysfs_create_group(&pdev->dev.kobj, &gta02_wlan_attr_group);
+	if (error) {
+		rfkill_free(rfkill);
+		return error;
+	}
+
+	dev_set_drvdata(&pdev->dev, rfkill);
 
-	return sysfs_create_group(&pdev->dev.kobj, &gta02_wlan_attr_group);
+	return 0;
 }
 
 static int gta02_wlan_remove(struct platform_device *pdev)
 {
+	struct rfkill *rfkill = dev_get_drvdata(&pdev->dev);
+
+	rfkill_unregister(rfkill);
+	rfkill_free(rfkill);
+
 	sysfs_remove_group(&pdev->dev.kobj, &gta02_wlan_attr_group);
 
 	return 0;