linux-kernel - [PATCH 05/13] eeprom: ee1004: Improve check for SMBUS features

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Date:   Mon, 24 May 2021 22:12:22 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH 05/13] eeprom: ee1004: Improve check for SMBUS features

We have to read 512 bytes only, therefore read performance isn't really
a concern. Don't bother the user if i2c block read isn't supported.

For i2c_smbus_read_i2c_block_data_or_emulated() to work it's sufficient
if I2C_FUNC_SMBUS_READ_I2C_BLOCK or I2C_FUNC_SMBUS_READ_BYTE_DATA is
supported. Therefore remove the check for I2C_FUNC_SMBUS_READ_WORD_DATA.

In addition check for I2C_FUNC_SMBUS_WRITE_BYTE (included in
I2C_FUNC_SMBUS_BYTE) which is needed for setting the page.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/misc/eeprom/ee1004.c | 22 ++++------------------
 1 file changed, 4 insertions(+), 18 deletions(-)

diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c
index b991ab250..0d497e0e4 100644
--- a/drivers/misc/eeprom/ee1004.c
+++ b/drivers/misc/eeprom/ee1004.c
@@ -167,23 +167,13 @@ static int ee1004_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	int err, cnr = 0;
-	const char *slow = NULL;
 
 	/* Make sure we can operate on this adapter */
 	if (!i2c_check_functionality(client->adapter,
-				     I2C_FUNC_SMBUS_READ_BYTE |
-				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
-		if (i2c_check_functionality(client->adapter,
-				     I2C_FUNC_SMBUS_READ_BYTE |
-				     I2C_FUNC_SMBUS_READ_WORD_DATA))
-			slow = "word";
-		else if (i2c_check_functionality(client->adapter,
-				     I2C_FUNC_SMBUS_READ_BYTE |
-				     I2C_FUNC_SMBUS_READ_BYTE_DATA))
-			slow = "byte";
-		else
-			return -EPFNOSUPPORT;
-	}
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_I2C_BLOCK) &&
+	    !i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_BYTE_DATA))
+		return -EPFNOSUPPORT;
 
 	/* Use 2 dummy devices for page select command */
 	mutex_lock(&ee1004_bus_lock);
@@ -218,10 +208,6 @@ static int ee1004_probe(struct i2c_client *client,
 	dev_info(&client->dev,
 		 "%u byte EE1004-compliant SPD EEPROM, read-only\n",
 		 EE1004_EEPROM_SIZE);
-	if (slow)
-		dev_notice(&client->dev,
-			   "Falling back to %s reads, performance will suffer\n",
-			   slow);
 
 	return 0;
 
-- 
2.31.1