From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Subject: Documentation issue on attaching new style drivers Date: Tue, 3 Jun 2008 11:34:50 +0100 Message-ID: <20080603103450.GA8391@fluff.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Quoting from Documentation/i2c/writing-clients, the section entitled "Standard Driver Model Binding ("New Style")" has the following paragraph: Drivers match devices when i2c_client.driver_name and the driver name are the same; this approach is used in several other busses that don't have device typing support in the hardware. The driver and module name should match, so hotplug/coldplug mechanisms will modprobe the driver. Having tried this whilst upgrading an old driver in my own tree, I found that this does not work, and that you need to supply your own idtable for the .id_table entry. I had a quick look in drivers/i2c/i2c-core.c and it seems that the only thing the .match entry i2c_device_match() is doing is checking the driver's id_table, as so: static int i2c_device_match(struct device *dev, struct device_driver *drv) { struct i2c_client *client = to_i2c_client(dev); struct i2c_driver *driver = to_i2c_driver(drv); /* make legacy i2c drivers bypass driver model probing entirely; * such drivers scan each i2c adapter/bus themselves. */ if (!is_newstyle_driver(driver)) return 0; /* match on an id table if there is one */ if (driver->id_table) return i2c_match_id(driver->id_table, client) != NULL; return 0; } Is the documentation wrong, and all drivers need to have an id_table in them, or is the i2c-core.c wrong for only checking the id_table entries? My suspicion is that everyone is using the id_table as this can be passed to the MODULE_DEVICE_TABLE() to allow autoloading of the relevant modules? Note, the i2c_probe function will correctly pass a NULL ID if there is no id_table present. -- Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/) 'a smiley only costs 4 bytes' _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c