Subject: Re: [PATCH 1/3] mfd: add support for Janz CMOD-IO PCI MODULbus Carrier Board

From: Wolfgang Grandegger <[email-masked]>
Date: Fri, 19 Mar 2010 16:35:29 +0100

Ira W. Snyder wrote:
> On Fri, Mar 19, 2010 at 10:13:10AM +0100, Wolfgang Grandegger wrote:
>> Ira W. Snyder wrote:
>>> The Janz CMOD-IO PCI MODULbus carrier board is a PCI to MODULbus bridge,
>>> which may host many different types of MODULbus daughterboards, including
>>> CAN and GPIO controllers.
>>>
>>> Signed-off-by: Ira W. Snyder <[email-masked]>
>>> Cc: Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/[email-masked]>
>> You can add my "Reviewed-by: Wolfgang Grandegger <[email-masked]>".
>>
>> Just one concern:
>>
>>> ---
>>>  drivers/mfd/Kconfig       |    8 +
>>>  drivers/mfd/Makefile      |    1 +
>>>  drivers/mfd/janz-cmodio.c |  339 +++++++++++++++++++++++++++++++++++++++++++++
>>>  include/linux/mfd/janz.h  |   54 +++++++
>>>  4 files changed, 402 insertions(+), 0 deletions(-)
>>>  create mode 100644 drivers/mfd/janz-cmodio.c
>>>  create mode 100644 include/linux/mfd/janz.h
>>>
>>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>>> index 8782978..f1858d7 100644
>>> --- a/drivers/mfd/Kconfig
>>> +++ b/drivers/mfd/Kconfig
>>> @@ -27,6 +27,14 @@ config MFD_SM501_GPIO
>>>  	 lines on the SM501. The platform data is used to supply the
>>>  	 base number for the first GPIO line to register.
>>>  
>>> +config MFD_JANZ_CMODIO
>>> +	tristate "Support for Janz CMOD-IO PCI MODULbus Carrier Board"
>>> +	---help---
>>> +	  This is the core driver for the Janz CMOD-IO PCI MODULbus
>>> +	  carrier board. This device is a PCI to MODULbus bridge which may
>>> +	  host many different types of MODULbus daughterboards, including
>>> +	  CAN and GPIO controllers.
>>> +
>>>  config MFD_ASIC3
>>>  	bool "Support for Compaq ASIC3"
>>>  	depends on GENERIC_HARDIRQS && GPIOLIB && ARM
>>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>>> index e09eb48..e8fa905 100644
>>> --- a/drivers/mfd/Makefile
>>> +++ b/drivers/mfd/Makefile
>>> @@ -3,6 +3,7 @@
>>>  #
>>>  
>>>  obj-$(CONFIG_MFD_SM501)		+= sm501.o
>>> +obj-$(CONFIG_MFD_JANZ_CMODIO)	+= janz-cmodio.o
>>>  obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
>>>  obj-$(CONFIG_MFD_SH_MOBILE_SDHI)		+= sh_mobile_sdhi.o
>>>  
>>> diff --git a/drivers/mfd/janz-cmodio.c b/drivers/mfd/janz-cmodio.c
>>> new file mode 100644
>>> index 0000000..914280e
>>> --- /dev/null
>>> +++ b/drivers/mfd/janz-cmodio.c
>>> @@ -0,0 +1,339 @@
>>> +/*
>>> + * Janz CMOD-IO MODULbus Carrier Board PCI Driver
>>> + *
>>> + * Copyright (c) 2010 Ira W. Snyder <[email-masked]>
>>> + *
>>> + * Lots of inspiration and code was copied from drivers/mfd/sm501.c
>>> + *
>>> + * 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; either version 2 of the License, or (at your
>>> + * option) any later version.
>>> + */
>>> +
>>> +#include <linux/kernel.h>
>>> +#include <linux/module.h>
>>> +#include <linux/init.h>
>>> +#include <linux/pci.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/platform_device.h>
>>> +
>>> +#include <linux/mfd/janz.h>
>>> +
>>> +#define DRV_NAME "janz-cmodio"
>>> +
>>> +/* Size of each MODULbus module in PCI BAR4 */
>>> +#define CMODIO_MODULBUS_SIZE	0x200
>>> +
>>> +/* Maximum number of MODULbus modules on a CMOD-IO carrier board */
>>> +#define CMODIO_MAX_MODULES	4
>>> +
>>> +/* Module Parameters */
>>> +static unsigned int num_modules = CMODIO_MAX_MODULES;
>>> +static unsigned char *modules[CMODIO_MAX_MODULES] = {
>>> +	"janz-ican3",
>>> +	"janz-ican3",
>>> +	"",
>>> +	"janz-ttl",
>>> +};
>> This is probably not a good default but just your private configuration.
>>
> 
> Yep, that's the configuration I have. Do you have any suggestions for a
> better default? I could make them all blank strings, which means "no
> daughtercard in this slot". That is my only idea for a different
> default.

That's probably better. And if no boards are defined via module
parameter, return with an error and print an error message telling the
user what to do. Also maybe s/""/"empty"/ and a better the
MODULE_DESCRIPTION could be useful.

Wolfgang.