From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Mon, 17 Jul 2017 17:13:28 +0300
Subject: i2c: core: Allow empty id_table in ACPI case as well
Git-commit: c64ffff7a9d1eee6624d3eaab36968fe6df31a9f
Patch-mainline: v4.13-rc5
References: git-fixes

For now empty ID table is not allowed with ACPI and prevents driver to
be probed.

Add a check to allow empty ID table.

This introduces a helper i2c_acpi_match_device().

Note, we rename some static function in i2c-core-acpi.c to distinguish
with public API.

Fixes: da10c06a044b ("i2c: Make I2C ID tables non-mandatory for DT'ed devices")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Rajmohan Mani <rajmohan.mani@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[wsa: needed to get some drivers probed again]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 drivers/i2c/i2c-core.c |   26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -290,6 +290,16 @@ static void i2c_acpi_register_devices(st
 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 }
 
+const struct acpi_device_id *
+i2c_acpi_match_device(const struct acpi_device_id *matches,
+		      struct i2c_client *client)
+{
+	if (!(client && matches))
+		return NULL;
+
+	return acpi_match_device(matches, &client->dev);
+}
+
 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
 					   void *data, void **return_value)
 {
@@ -349,7 +359,7 @@ u32 i2c_acpi_find_bus_speed(struct devic
 }
 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
 
-static int i2c_acpi_match_adapter(struct device *dev, void *data)
+static int i2c_acpi_find_match_adapter(struct device *dev, void *data)
 {
 	struct i2c_adapter *adapter = i2c_verify_adapter(dev);
 
@@ -359,7 +369,7 @@ static int i2c_acpi_match_adapter(struct
 	return ACPI_HANDLE(dev) == (acpi_handle)data;
 }
 
-static int i2c_acpi_match_device(struct device *dev, void *data)
+static int i2c_acpi_find_match_device(struct device *dev, void *data)
 {
 	return ACPI_COMPANION(dev) == data;
 }
@@ -369,7 +379,7 @@ static struct i2c_adapter *i2c_acpi_find
 	struct device *dev;
 
 	dev = bus_find_device(&i2c_bus_type, NULL, handle,
-			      i2c_acpi_match_adapter);
+			      i2c_acpi_find_match_adapter);
 	return dev ? i2c_verify_adapter(dev) : NULL;
 }
 
@@ -377,7 +387,8 @@ static struct i2c_client *i2c_acpi_find_
 {
 	struct device *dev;
 
-	dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_match_device);
+	dev = bus_find_device(&i2c_bus_type, NULL, adev,
+			      i2c_acpi_find_match_device);
 	return dev ? i2c_verify_client(dev) : NULL;
 }
 
@@ -472,6 +483,12 @@ EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 #else /* CONFIG_ACPI */
 static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
 extern struct notifier_block i2c_acpi_notifier;
+static inline const struct acpi_device_id *
+i2c_acpi_match_device(const struct acpi_device_id *matches,
+		      struct i2c_client *client)
+{
+	return NULL;
+}
 #endif /* CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI_I2C_OPREGION
@@ -1013,6 +1030,7 @@ static int i2c_device_probe(struct devic
 	 * Tree match table entry is supplied for the probing device.
 	 */
 	if (!driver->id_table &&
+	    !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 	    !i2c_of_match_device(dev->driver->of_match_table, client))
 		return -ENODEV;