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media: usb: hdpvr: use I2C core to handle only supported messages

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The HW can only do write-then-read transactions. This is a common
limitation, so we can add an adapter quirk flag to let the I2C core
enforce the checks instead of open coding them.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
This commit is contained in:
Wolfram Sang
2025-06-17 10:35:15 +02:00
committed by Hans Verkuil
parent b5ae5a7982
commit 1cb109d886
1 changed files with 4 additions and 24 deletions
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drivers/media/usb/hdpvr/hdpvr-i2c.c
+4 -24
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@@ -124,32 +124,12 @@ static int hdpvr_transfer(struct i2c_adapter *i2c_adapter, struct i2c_msg *msgs,
else
retval = hdpvr_i2c_write(dev, 1, addr, msgs[0].buf,
msgs[0].len);
} else if (num == 2) {
if (msgs[0].addr != msgs[1].addr) {
v4l2_warn(&dev->v4l2_dev, "refusing 2-phase i2c xfer with conflicting target addresses\n");
retval = -EINVAL;
goto out;
}
if ((msgs[0].flags & I2C_M_RD) || !(msgs[1].flags & I2C_M_RD)) {
v4l2_warn(&dev->v4l2_dev, "refusing complex xfer with r0=%d, r1=%d\n",
msgs[0].flags & I2C_M_RD,
msgs[1].flags & I2C_M_RD);
retval = -EINVAL;
goto out;
}
/*
* Write followed by atomic read is the only complex xfer that
* we actually support here.
*/
} else {
/* do write-then-read */
retval = hdpvr_i2c_read(dev, 1, addr, msgs[0].buf, msgs[0].len,
msgs[1].buf, msgs[1].len);
} else {
v4l2_warn(&dev->v4l2_dev, "refusing %d-phase i2c xfer\n", num);
}
out:
mutex_unlock(&dev->i2c_mutex);
return retval ? retval : num;
@@ -165,9 +145,9 @@ static const struct i2c_algorithm hdpvr_algo = {
.functionality = hdpvr_functionality,
};
/* prevent invalid 0-length usb_control_msg */
/* prevent invalid 0-length usb_control_msg and support only write-then-read */
static const struct i2c_adapter_quirks hdpvr_quirks = {
.flags = I2C_AQ_NO_ZERO_LEN_READ,
.flags = I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_COMB_WRITE_THEN_READ,
};
static const struct i2c_adapter hdpvr_i2c_adapter_template = {