It is good practice to check that the underlying adapter supports
I2C transfers before attempting them. The i2c core would eventually
return an error, but it's more efficient to fail early.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
---
Not sure about that one, opinions welcome.
drivers/i2c/i2c-dev.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- linux-6.9.orig/drivers/i2c/i2c-dev.c
+++ linux-6.9/drivers/i2c/i2c-dev.c
@@ -139,6 +139,10 @@ static ssize_t i2cdev_read(struct file *
struct i2c_client *client = file->private_data;
+ /* Adapter must support I2C transfers */
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -EOPNOTSUPP;
+
if (count > 8192)
count = 8192;
@@ -163,6 +167,10 @@ static ssize_t i2cdev_write(struct file
char *tmp;
struct i2c_client *client = file->private_data;
+ /* Adapter must support I2C transfers */
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -EOPNOTSUPP;
+
if (count > 8192)
count = 8192;
@@ -238,6 +246,10 @@ static noinline int i2cdev_ioctl_rdwr(st
u8 __user **data_ptrs;
int i, res;
+ /* Adapter must support I2C transfers */
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -EOPNOTSUPP;
+
data_ptrs = kmalloc_array(nmsgs, sizeof(u8 __user *), GFP_KERNEL);
if (data_ptrs == NULL) {
kfree(msgs);
--
Jean Delvare
SUSE L3 Support
