1 files changed, 118 insertions, 40 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index df937df845eb..6649176de940 100644
--- a/drivers/i2c/i2c-core.c
+++ b/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;
@@ -975,7 +1054,7 @@ 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,
@@ -983,7 +1062,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
                 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);