i2c/powermac: Register i2c devices from device-tree

This causes i2c-powermac to register i2c devices exposed in the
device-tree, enabling new-style probing of devices.

Note that we prefix the IDs with "MAC," in order to prevent the
generic drivers from matching. This is done on purpose as we only
want drivers specifically tested/designed to operate on powermacs
to match.

This removes the special case we had for the AMS driver, and updates
the driver's match table instead.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 73 insertions, 28 deletions

diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index 03685a329d7d..fc536f2971c0 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -1503,6 +1503,7 @@ static int __init pmac_i2c_create_platform_devices(void)
                 if (bus->platform_dev == NULL)
                         return -ENOMEM;
                 bus->platform_dev->dev.platform_data = bus;
+                bus->platform_dev->dev.of_node = bus->busnode;
                 platform_device_add(bus->platform_dev);
         }
 
diff --git a/drivers/i2c/busses/i2c-powermac.c b/drivers/i2c/busses/i2c-powermac.c
index 7b397c6f607e..31c47e18d83c 100644
--- a/drivers/i2c/busses/i2c-powermac.c
+++ b/drivers/i2c/busses/i2c-powermac.c
@@ -227,6 +227,72 @@ static int __devexit i2c_powermac_remove(struct platform_device *dev)
         return 0;
 }
 
+static void __devinit i2c_powermac_register_devices(struct i2c_adapter *adap,
+                                                    struct pmac_i2c_bus *bus)
+{
+        struct i2c_client *newdev;
+        struct device_node *node;
+
+        for_each_child_of_node(adap->dev.of_node, node) {
+                struct i2c_board_info info = {};
+                struct dev_archdata dev_ad = {};
+                const __be32 *reg;
+                char tmp[16];
+                u32 addr;
+                int len;
+
+                /* Get address & channel */
+                reg = of_get_property(node, "reg", &len);
+                if (!reg || (len < sizeof(int))) {
+                        dev_err(&adap->dev, "i2c-powermac: invalid reg on %s\n",
+                                node->full_name);
+                        continue;
+                }
+                addr = be32_to_cpup(reg);
+
+                /* Multibus setup, check channel */
+                if (!pmac_i2c_match_adapter(node, adap))
+                        continue;
+
+                dev_dbg(&adap->dev, "i2c-powermac: register %s\n",
+                        node->full_name);
+
+                /* Make up a modalias. Note: we to _NOT_ want the standard
+                 * i2c drivers to match with any of our powermac stuff
+                 * unless they have been specifically modified to handle
+                 * it on a case by case basis. For example, for thermal
+                 * control, things like lm75 etc... shall match with their
+                 * corresponding windfarm drivers, _NOT_ the generic ones,
+                 * so we force a prefix of AAPL, onto the modalias to
+                 * make that happen
+                 */
+                if (of_modalias_node(node, tmp, sizeof(tmp)) < 0) {
+                        dev_err(&adap->dev, "i2c-powermac: modalias failure"
+                                " on %s\n", node->full_name);
+                        continue;
+                }
+                snprintf(info.type, sizeof(info.type), "MAC,%s", tmp);
+
+                /* Fill out the rest of the info structure */
+                info.addr = (addr & 0xff) >> 1;
+                info.irq = irq_of_parse_and_map(node, 0);
+                info.of_node = of_node_get(node);
+                info.archdata = &dev_ad;
+
+                newdev = i2c_new_device(adap, &info);
+                if (!newdev) {
+                        dev_err(&adap->dev, "i2c-powermac: Failure to register"
+                                " %s\n", node->full_name);
+                        of_node_put(node);
+                        /* We do not dispose of the interrupt mapping on
+                         * purpose. It's not necessary (interrupt cannot be
+                         * re-used) and somebody else might have grabbed it
+                         * via direct DT lookup so let's not bother
+                         */
+                        continue;
+                }
+        }
+}
 
 static int __devinit i2c_powermac_probe(struct platform_device *dev)
 {
@@ -272,6 +338,7 @@ static int __devinit i2c_powermac_probe(struct platform_device *dev)
         adapter->algo = &i2c_powermac_algorithm;
         i2c_set_adapdata(adapter, bus);
         adapter->dev.parent = &dev->dev;
+        adapter->dev.of_node = dev->dev.of_node;
         rc = i2c_add_adapter(adapter);
         if (rc) {
                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
@@ -281,33 +348,10 @@ static int __devinit i2c_powermac_probe(struct platform_device *dev)
 
         printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
 
-        if (!strncmp(basename, "uni-n", 5)) {
-                struct device_node *np;
-                const u32 *prop;
-                struct i2c_board_info info;
-
-                /* Instantiate I2C motion sensor if present */
-                np = of_find_node_by_name(NULL, "accelerometer");
-                if (np && of_device_is_compatible(np, "AAPL,accelerometer_1") &&
-                    (prop = of_get_property(np, "reg", NULL))) {
-                        int i2c_bus;
-                        const char *tmp_bus;
-
-                        /* look for bus either using "reg" or by path */
-                        tmp_bus = strstr(np->full_name, "/i2c-bus@");
-                        if (tmp_bus)
-                                i2c_bus = *(tmp_bus + 9) - '0';
-                        else
-                                i2c_bus = ((*prop) >> 8) & 0x0f;
-
-                        if (pmac_i2c_get_channel(bus) == i2c_bus) {
-                                memset(&info, 0, sizeof(struct i2c_board_info));
-                                info.addr = ((*prop) & 0xff) >> 1;
-                                strlcpy(info.type, "ams", I2C_NAME_SIZE);
-                                i2c_new_device(adapter, &info);
-                        }
-                }
-        }
+        /* Cannot use of_i2c_register_devices() due to Apple device-tree
+         * funkyness
+         */
+        i2c_powermac_register_devices(adapter, bus);
 
         return rc;
 }
diff --git a/drivers/macintosh/ams/ams-i2c.c b/drivers/macintosh/ams/ams-i2c.c
index abeecd27b484..978eda8d6678 100644
--- a/drivers/macintosh/ams/ams-i2c.c
+++ b/drivers/macintosh/ams/ams-i2c.c
@@ -65,7 +65,7 @@ static int ams_i2c_probe(struct i2c_client *client,
 static int ams_i2c_remove(struct i2c_client *client);
 
 static const struct i2c_device_id ams_id[] = {
-        { "ams", 0 },
+        { "MAC,accelerometer_1", 0 },
         { }
 };
 MODULE_DEVICE_TABLE(i2c, ams_id);