Re: [PATCH v4 1/3] mfd: add support for Diolan DLN-2 devices

[Lee Jones <lee.jones@xxxxxxxxxx>]

On Tue, 09 Sep 2014, Octavian Purdila wrote:

> This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
> Master Adapter DLN-2. Details about the device can be found here:
> 
> https://www.diolan.com/i2c/i2c_interface.html.
> 
> Information about the USB protocol can be found in the Programmer's
> Reference Manual [1], see section 1.7.

This driver really needs a USB Ack before I can accept it.

> Because the hardware has a single transmit endpoint and a single
> receive endpoint the communication between the various DLN2 drivers
> and the hardware will be muxed/demuxed by this driver.
> 
> Each DLN2 module will be identified by the handle field within the DLN2
> message header. If a DLN2 module issues multiple commands in parallel
> they will be identified by the echo counter field in the message header.
> 
> The DLN2 modules can use the dln2_transfer() function to issue a
> command and wait for its response. They can also register a callback
> that is going to be called when a specific event id is generated by
> the device (e.g. GPIO interrupts). The device uses handle 0 for
> sending events.
> 
> [1] https://www.diolan.com/downloads/dln-api-manual.pdf
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx>
> ---
>  drivers/mfd/Kconfig      |   9 +
>  drivers/mfd/Makefile     |   1 +
>  drivers/mfd/dln2.c       | 681 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/dln2.h |  71 +++++
>  4 files changed, 762 insertions(+)
>  create mode 100644 drivers/mfd/dln2.c
>  create mode 100644 include/linux/mfd/dln2.h

[...]

> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
> new file mode 100644
> index 0000000..b551b5e
> --- /dev/null
> +++ b/drivers/mfd/dln2.c
> @@ -0,0 +1,681 @@
> +/*
> + * Driver for the Diolan DLN-2 USB adapter
> + *
> + * Copyright (c) 2014 Intel Corporation
> + *
> + * Derived from:
> + *  i2c-diolan-u2c.c
> + *  Copyright (c) 2010-2011 Ericsson AB
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation, version 2.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>

What are you using this for?

> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +#include <linux/i2c.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/dln2.h>
> +
> +#define DRIVER_NAME			"usb-dln2"

Don't do this, just use "usb-dln2" where it needs to be used.

[...]

> +static struct usb_driver dln2_driver = {
> +	.name = DRIVER_NAME,
> +	.probe = dln2_probe,
> +	.disconnect = dln2_disconnect,
> +	.id_table = dln2_table,
> +};
> +
> +module_usb_driver(dln2_driver);
> +
> +MODULE_AUTHOR("Octavian Purdila <octavian.purdila@xxxxxxxxx>");
> +MODULE_DESCRIPTION(DRIVER_NAME " driver");

This is not a description.

> +MODULE_LICENSE("GPL");

Header says v2.

> diff --git a/include/linux/mfd/dln2.h b/include/linux/mfd/dln2.h
> new file mode 100644
> index 0000000..197565d
> --- /dev/null
> +++ b/include/linux/mfd/dln2.h
> @@ -0,0 +1,71 @@
> +#ifndef __LINUX_USB_DLN2_H
> +#define __LINUX_USB_DLN2_H
> +
> +#define DLN2_CMD(cmd, id)		((cmd) | ((id) << 8))
> +
> +struct dln2_platform_data {
> +	u16 handle;
> +	union {
> +		struct {
> +			u8 port;
> +		} i2c;
> +	};
> +};

Why this complexity?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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