[v14,2/2] usb: typec: ucsi: add support for Cypress CCGx

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: ajayg@nvidia.com
Cc: wsa@the-dreams.de, heikki.krogerus@linux.intel.com,
	peda@axentia.se, linux-usb@vger.kernel.org,
	linux-i2c@vger.kernel.org
Subject: [v14,2/2] usb: typec: ucsi: add support for Cypress CCGx
Date: Fri, 26 Oct 2018 15:18:51 +0300	[thread overview]
Message-ID: <20181026121851.GF10650@smile.fi.intel.com> (raw)

On Thu, Oct 25, 2018 at 03:33:53PM -0700, ajayg@nvidia.com wrote:

> Latest NVIDIA GPU cards have a Cypress CCGx Type-C controller
> over I2C interface.
> 
> This UCSI I2C driver uses I2C bus driver interface for communicating
> with Type-C controller.

> +	/*
> +	 * Flush CCGx RESPONSE queue by acking interrupts. Above ucsi control
> +	 * register write will push response which must be cleared.
> +	 */
> +	do {
> +		status = ccg_read(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
> +		if (status < 0)
> +			return status;
> +
> +		if (!data)
> +			return 0;
> +
> +		status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
> +		if (status < 0)
> +			return status;
> +
> +		usleep_range(10000, 11000);
> +	} while (data && --count);

I don't see any point to check data here. How can it be different from the
check above?

> +	return -ETIMEDOUT;