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From:   Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To:     Wolfram Sang <wsa@kernel.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>
Cc:     linux-i2c@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: [PATCH 1/2] i2c: consider devices with of_match_table during i2c device probing
Date:   Wed, 26 Aug 2020 13:29:37 +0900
Message-Id: <20200826042938.3259-1-sergey.senozhatsky@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Unlike acpi_match_device(), acpi_driver_match_device() does
consider devices that provide of_match_table and performs
of_compatible() matching for such devices. The key point here is
that ACPI of_compatible() matching - acpi_of_match_device() - is
part of ACPI and does not depend on CONFIG_OF.

Consider the following case:
o !CONFIG_OF system
o probing of i2c device that provides .of_match_table, but no .id_table

 i2c_device_probe()
 ...
   if (!driver->id_table &&
       !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
       !i2c_of_match_device(dev->driver->of_match_table, client)) {
       status = -ENODEV;
       goto put_sync_adapter;
   }

i2c_of_match_device() depends on CONFIG_OF and, thus, is always false.
i2c_acpi_match_device() does ACPI match only, no of_comtatible() matching
takes place, even though the device provides .of_match_table and ACPI,
technically, is capable of matching such device. The result is -ENODEV.
Probing will succeed, however, if we'd use .of_match_table aware ACPI
matching.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 drivers/i2c/i2c-core-acpi.c | 10 ++++------
 drivers/i2c/i2c-core-base.c |  2 +-
 drivers/i2c/i2c-core.h      | 10 +++-------
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 2ade99b105b9..1dd152ae75e5 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -276,14 +276,12 @@ void i2c_acpi_register_devices(struct i2c_adapter *adap)
 		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)
+bool i2c_acpi_match_device(struct device *dev, struct i2c_client *client)
 {
-	if (!(client && matches))
-		return NULL;
+	if (!client)
+		return false;
 
-	return acpi_match_device(matches, &client->dev);
+	return acpi_driver_match_device(&client->dev, dev->driver);
 }
 
 static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 34a9609f256d..35ec6335852b 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -480,7 +480,7 @@ static int i2c_device_probe(struct device *dev)
 	 * or ACPI ID table is supplied for the probing device.
 	 */
 	if (!driver->id_table &&
-	    !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
+	    !i2c_acpi_match_device(dev, client) &&
 	    !i2c_of_match_device(dev->driver->of_match_table, client)) {
 		status = -ENODEV;
 		goto put_sync_adapter;
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
index 94ff1693b391..7ee6a6e3fb8d 100644
--- a/drivers/i2c/i2c-core.h
+++ b/drivers/i2c/i2c-core.h
@@ -59,19 +59,15 @@ static inline int __i2c_check_suspended(struct i2c_adapter *adap)
 }
 
 #ifdef CONFIG_ACPI
-const struct acpi_device_id *
-i2c_acpi_match_device(const struct acpi_device_id *matches,
-		      struct i2c_client *client);
+bool i2c_acpi_match_device(struct device *dev, struct i2c_client *client);
 void i2c_acpi_register_devices(struct i2c_adapter *adap);
 
 int i2c_acpi_get_irq(struct i2c_client *client);
 #else /* CONFIG_ACPI */
 static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
-static inline const struct acpi_device_id *
-i2c_acpi_match_device(const struct acpi_device_id *matches,
-		      struct i2c_client *client)
+bool i2c_acpi_match_device(struct device *dev, struct i2c_client *client)
 {
-	return NULL;
+	return false;
 }
 
 static inline int i2c_acpi_get_irq(struct i2c_client *client)
-- 
2.28.0