Re: [PATCH v4 2/3] i2c: add support for Cypress CYUSBS234 USB-I2C adapter

Wolfram Sang
2014-12-03T11:08:09Z

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Hi,

thanks for this submission. Looks like an interesting device. However,
some very high level questions first:

> +/*
> + * It exposes sysfs entries under the i2c adapter for getting the i2c transfer
> + * status, reset i2c read/write module, get/set nak and stop bits.
> + */

Yes, I see that. Yet, I don't know why they are needed? The driver
should know when to send NAK/STOP. Why expose that to the user? And why
do we need a reset? Are there stability problems? What about unloading
the module? And what is the use case for reading the status?

> + if (num > 1) {
> + dev_err(&adapter->dev, "i2c_msg number is > 1\n");
> + return -EIO;
> + }

Ouch! Don't you have any repeated start option somewhere?

Thanks,

Wolfram

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