From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH v4 2/3] i2c: add support for Cypress CYUSBS234 USB-I2C
 adapter
Date: Wed, 3 Dec 2014 12:07:55 +0100
Message-ID: <20141203110755.GA1039@katana>
References: <1417241986-17841-1-git-send-email-muth@cypress.com>
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In-Reply-To: <1417241986-17841-1-git-send-email-muth@cypress.com>
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To: Muthu Mani <muth@cypress.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>, Lee Jones <lee.jones@linaro.org>, Linus Walleij <linus.walleij@linaro.org>, Alexandre Courbot <gnurou@gmail.com>, gregkh@linuxfoundation.org, Johan Hovold <johan@kernel.org>, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, linux-gpio@vger.kernel.org, Rajaram Regupathy <rera@cypress.com>
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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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