From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: [PATCH 1/2] i2c: core: Allow the driver to override the default i2c_bus match behavior Date: Sat, 22 Jul 2017 20:55:36 +0200 Message-ID: <20170722185537.12696-1-hdegoede@redhat.com> Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50050 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750865AbdGVSzl (ORCPT ); Sat, 22 Jul 2017 14:55:41 -0400 Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Jiri Kosina , Benjamin Tissoires , Wolfram Sang Cc: Hans de Goede , linux-input@vger.kernel.org, linux-i2c@vger.kernel.org Some ACPI devices report multiple ids for a single i2c_client, while not really implementing the hw-interface asociated with some of these ids. For some of these devices calling probe and having probe fail with -ENODEV is a problem in itself as this causes the device to be powered-up and down again (causes its PS0 and PS3 ACPI methods to be executed) which puts some devices in an unusable state. This commit adds a match callback to i2c_driver, allowing drivers to override the default i2c_bus match behavior and tell the core they are not the right driver for the device, avoiding i2c_bus_type.probe getting called, avoiding the undesirable power up / down cycle. Signed-off-by: Hans de Goede --- drivers/i2c/i2c-core-base.c | 12 +++++++++--- include/linux/i2c.h | 6 ++++++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index c89dac7fd2e7..2c6702f2347b 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -98,8 +98,16 @@ EXPORT_SYMBOL_GPL(i2c_match_id); static int i2c_device_match(struct device *dev, struct device_driver *drv) { struct i2c_client *client = i2c_verify_client(dev); - struct i2c_driver *driver; + struct i2c_driver *driver = to_i2c_driver(drv); + int ret; + if (driver->match && client) { + ret = driver->match(client); + if (ret < 0) + return 0; + if (ret > 0) + return 1; + } /* Attempt an OF style match */ if (i2c_of_match_device(drv->of_match_table, client)) @@ -109,8 +117,6 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv) if (acpi_driver_match_device(dev, drv)) return 1; - driver = to_i2c_driver(drv); - /* Finally an I2C match */ if (i2c_match_id(driver->id_table, client)) return 1; diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 00ca5b86a753..670577c82bc3 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -139,6 +139,9 @@ enum i2c_alert_protocol { * struct i2c_driver - represent an I2C device driver * @class: What kind of i2c device we instantiate (for detect) * @attach_adapter: Callback for bus addition (deprecated) + * @match: Allows the driver to override the default i2c_bus match behavior + * return < 0 to fail the match, > 0 to force a match, 0 to fallback + * to default id matching * @probe: Callback for device binding - soon to be deprecated * @probe_new: New callback for device binding * @remove: Callback for device unbinding @@ -180,6 +183,9 @@ struct i2c_driver { */ int (*attach_adapter)(struct i2c_adapter *) __deprecated; + /* Set this to override standard i2c_bus match behavior */ + int (*match)(struct i2c_client *); + /* Standard driver model interfaces */ int (*probe)(struct i2c_client *, const struct i2c_device_id *); int (*remove)(struct i2c_client *); -- 2.13.0