Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/ke…

…rnel/git/jdelvare/staging

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c: I2C bus multiplexer driver pca954x
  i2c: Multiplexed I2C bus core support
  i2c: Use a separate mutex for userspace client lists
  i2c: Make i2c_default_probe self-sufficient
  i2c: Drop dummy variable
  i2c: Move adapter locking helpers to i2c-core
  V4L/DVB: Use custom I2C probing function mechanism
  i2c: Add support for custom probe function
  i2c-dev: Use memdup_user
  i2c-dev: Remove unnecessary kmalloc casts

Documentation/i2c/instantiating-devices

@@ -102,7 +102,7 @@ static int __devinit usb_hcd_pnx4008_probe(struct platform_device *pdev)
 	memset(&i2c_info, 0, sizeof(struct i2c_board_info));
 	strlcpy(i2c_info.name, "isp1301_pnx", I2C_NAME_SIZE);
 	isp1301_i2c_client = i2c_new_probed_device(i2c_adap, &i2c_info,
-						   normal_i2c);
+						   normal_i2c, NULL);
 	i2c_put_adapter(i2c_adap);
 	(...)
 }

drivers/i2c/Kconfig

@@ -47,6 +47,19 @@ config I2C_CHARDEV
 	  This support is also available as a module.  If so, the module 
 	  will be called i2c-dev.
 
+config I2C_MUX
+	tristate "I2C bus multiplexing support"
+	depends on EXPERIMENTAL
+	help
+	  Say Y here if you want the I2C core to support the ability to
+	  handle multiplexed I2C bus topologies, by presenting each
+	  multiplexed segment as a I2C adapter.
+
+	  This support is also available as a module.  If so, the module
+	  will be called i2c-mux.
+
+source drivers/i2c/muxes/Kconfig
+
 config I2C_HELPER_AUTO
 	bool "Autoselect pertinent helper modules"
 	default y

drivers/i2c/Makefile

@@ -6,7 +6,8 @@ obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
 obj-$(CONFIG_I2C)		+= i2c-core.o
 obj-$(CONFIG_I2C_SMBUS)		+= i2c-smbus.o
 obj-$(CONFIG_I2C_CHARDEV)	+= i2c-dev.o
-obj-y				+= algos/ busses/
+obj-$(CONFIG_I2C_MUX)		+= i2c-mux.o
+obj-y				+= algos/ busses/ muxes/
 
 ifeq ($(CONFIG_I2C_DEBUG_CORE),y)
 EXTRA_CFLAGS += -DDEBUG

drivers/i2c/i2c-core.c

@@ -20,7 +20,9 @@
 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
    All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
    SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
-   Jean Delvare <khali@linux-fr.org> */
+   Jean Delvare <khali@linux-fr.org>
+   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
+   Michael Lawnick <michael.lawnick.ext@nsn.com> */
 
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -423,11 +425,87 @@ static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 	return 0;
 }
 
+/* walk up mux tree */
+static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
+{
+	int result;
+
+	result = device_for_each_child(&adapter->dev, &addr,
+					__i2c_check_addr_busy);
+
+	if (!result && i2c_parent_is_i2c_adapter(adapter))
+		result = i2c_check_mux_parents(
+				    to_i2c_adapter(adapter->dev.parent), addr);
+
+	return result;
+}
+
+/* recurse down mux tree */
+static int i2c_check_mux_children(struct device *dev, void *addrp)
+{
+	int result;
+
+	if (dev->type == &i2c_adapter_type)
+		result = device_for_each_child(dev, addrp,
+						i2c_check_mux_children);
+	else
+		result = __i2c_check_addr_busy(dev, addrp);
+
+	return result;
+}
+
 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 {
-	return device_for_each_child(&adapter->dev, &addr,
-				     __i2c_check_addr_busy);
+	int result = 0;
+
+	if (i2c_parent_is_i2c_adapter(adapter))
+		result = i2c_check_mux_parents(
+				    to_i2c_adapter(adapter->dev.parent), addr);
+
+	if (!result)
+		result = device_for_each_child(&adapter->dev, &addr,
+						i2c_check_mux_children);
+
+	return result;
+}
+
+/**
+ * i2c_lock_adapter - Get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+	if (i2c_parent_is_i2c_adapter(adapter))
+		i2c_lock_adapter(to_i2c_adapter(adapter->dev.parent));
+	else
+		rt_mutex_lock(&adapter->bus_lock);
+}
+EXPORT_SYMBOL_GPL(i2c_lock_adapter);
+
+/**
+ * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+static int i2c_trylock_adapter(struct i2c_adapter *adapter)
+{
+	if (i2c_parent_is_i2c_adapter(adapter))
+		return i2c_trylock_adapter(to_i2c_adapter(adapter->dev.parent));
+	else
+		return rt_mutex_trylock(&adapter->bus_lock);
+}
+
+/**
+ * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+	if (i2c_parent_is_i2c_adapter(adapter))
+		i2c_unlock_adapter(to_i2c_adapter(adapter->dev.parent));
+	else
+		rt_mutex_unlock(&adapter->bus_lock);
 }
+EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
 
 /**
  * i2c_new_device - instantiate an i2c device
@@ -633,9 +711,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 		return -EINVAL;
 
 	/* Keep track of the added device */
-	i2c_lock_adapter(adap);
+	mutex_lock(&adap->userspace_clients_lock);
 	list_add_tail(&client->detected, &adap->userspace_clients);
-	i2c_unlock_adapter(adap);
+	mutex_unlock(&adap->userspace_clients_lock);
 	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 		 info.type, info.addr);
 
@@ -674,7 +752,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
 
 	/* Make sure the device was added through sysfs */
 	res = -ENOENT;
-	i2c_lock_adapter(adap);
+	mutex_lock(&adap->userspace_clients_lock);
 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
 				 detected) {
 		if (client->addr == addr) {
@@ -687,7 +765,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
 			break;
 		}
 	}
-	i2c_unlock_adapter(adap);
+	mutex_unlock(&adap->userspace_clients_lock);
 
 	if (res < 0)
 		dev_err(dev, "%s: Can't find device in list\n",
@@ -714,10 +792,11 @@ static const struct attribute_group *i2c_adapter_attr_groups[] = {
 	NULL
 };
 
-static struct device_type i2c_adapter_type = {
+struct device_type i2c_adapter_type = {
 	.groups		= i2c_adapter_attr_groups,
 	.release	= i2c_adapter_dev_release,
 };
+EXPORT_SYMBOL_GPL(i2c_adapter_type);
 
 #ifdef CONFIG_I2C_COMPAT
 static struct class_compat *i2c_adapter_compat_class;
@@ -760,7 +839,7 @@ static int __process_new_adapter(struct device_driver *d, void *data)
 
 static int i2c_register_adapter(struct i2c_adapter *adap)
 {
-	int res = 0, dummy;
+	int res = 0;
 
 	/* Can't register until after driver model init */
 	if (unlikely(WARN_ON(!i2c_bus_type.p))) {
@@ -769,6 +848,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	}
 
 	rt_mutex_init(&adap->bus_lock);
+	mutex_init(&adap->userspace_clients_lock);
 	INIT_LIST_HEAD(&adap->userspace_clients);
 
 	/* Set default timeout to 1 second if not already set */
@@ -801,8 +881,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 
 	/* Notify drivers */
 	mutex_lock(&core_lock);
-	dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
-				 __process_new_adapter);
+	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
 	mutex_unlock(&core_lock);
 
 	return 0;
@@ -975,15 +1054,15 @@ int i2c_del_adapter(struct i2c_adapter *adap)
 		return res;
 
 	/* Remove devices instantiated from sysfs */
-	i2c_lock_adapter(adap);
+	mutex_lock(&adap->userspace_clients_lock);
 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
 				 detected) {
 		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
 			client->addr);
 		list_del(&client->detected);
 		i2c_unregister_device(client);
 	}
-	i2c_unlock_adapter(adap);
+	mutex_unlock(&adap->userspace_clients_lock);
 
 	/* Detach any active clients. This can't fail, thus we do not
 	   checking the returned value. */
@@ -1238,12 +1317,12 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 #endif
 
 		if (in_atomic() || irqs_disabled()) {
-			ret = rt_mutex_trylock(&adap->bus_lock);
+			ret = i2c_trylock_adapter(adap);
 			if (!ret)
 				/* I2C activity is ongoing. */
 				return -EAGAIN;
 		} else {
-			rt_mutex_lock(&adap->bus_lock);
+			i2c_lock_adapter(adap);
 		}
 
 		/* Retry automatically on arbitration loss */
@@ -1255,7 +1334,7 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 			if (time_after(jiffies, orig_jiffies + adap->timeout))
 				break;
 		}
-		rt_mutex_unlock(&adap->bus_lock);
+		i2c_unlock_adapter(adap);
 
 		return ret;
 	} else {
@@ -1350,13 +1429,17 @@ static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
 				     I2C_SMBUS_BYTE_DATA, &dummy);
 	else
 #endif
-	if ((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50
-	 || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
-		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
-				     I2C_SMBUS_BYTE, &dummy);
-	else
+	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
+	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
 				     I2C_SMBUS_QUICK, NULL);
+	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
+		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
+				     I2C_SMBUS_BYTE, &dummy);
+	else {
+		dev_warn(&adap->dev, "No suitable probing method supported\n");
+		err = -EOPNOTSUPP;
+	}
 
 	return err >= 0;
 }
@@ -1437,16 +1520,6 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
 	if (!(adapter->class & driver->class))
 		goto exit_free;
 
-	/* Stop here if the bus doesn't support probing */
-	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE)) {
-		if (address_list[0] == I2C_CLIENT_END)
-			goto exit_free;
-
-		dev_warn(&adapter->dev, "Probing not supported\n");
-		err = -EOPNOTSUPP;
-		goto exit_free;
-	}
-
 	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
 		dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
 			"addr 0x%02x\n", adap_id, address_list[i]);
@@ -1461,18 +1534,23 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
 	return err;
 }
 
+int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
+{
+	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
+			      I2C_SMBUS_QUICK, NULL) >= 0;
+}
+EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
+
 struct i2c_client *
 i2c_new_probed_device(struct i2c_adapter *adap,
 		      struct i2c_board_info *info,
-		      unsigned short const *addr_list)
+		      unsigned short const *addr_list,
+		      int (*probe)(struct i2c_adapter *, unsigned short addr))
 {
 	int i;
 
-	/* Stop here if the bus doesn't support probing */
-	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) {
-		dev_err(&adap->dev, "Probing not supported\n");
-		return NULL;
-	}
+	if (!probe)
+		probe = i2c_default_probe;
 
 	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
 		/* Check address validity */
@@ -1490,7 +1568,7 @@ i2c_new_probed_device(struct i2c_adapter *adap,
 		}
 
 		/* Test address responsiveness */
-		if (i2c_default_probe(adap, addr_list[i]))
+		if (probe(adap, addr_list[i]))
 			break;
 	}
 
@@ -2002,7 +2080,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
 	flags &= I2C_M_TEN | I2C_CLIENT_PEC;
 
 	if (adapter->algo->smbus_xfer) {
-		rt_mutex_lock(&adapter->bus_lock);
+		i2c_lock_adapter(adapter);
 
 		/* Retry automatically on arbitration loss */
 		orig_jiffies = jiffies;
@@ -2016,7 +2094,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
 				       orig_jiffies + adapter->timeout))
 				break;
 		}
-		rt_mutex_unlock(&adapter->bus_lock);
+		i2c_unlock_adapter(adapter);
 	} else
 		res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
 					      command, protocol, data);