linux-kernel - Re: [PATCH] power: bq27x00_battery: Export all battery registers via sysfs

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Message-ID: <5151FC65.80409@metafoo.de>
Date:	Tue, 26 Mar 2013 20:52:05 +0100
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Pali Rohár <pali.rohar@...il.com>
CC:	Anton Vorontsov <cbouatmailru@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] power: bq27x00_battery: Export all battery registers
 via sysfs

On 03/26/2013 08:27 PM, Pali Rohár wrote:
> On Sunday 20 January 2013 10:53:01 Lars-Peter Clausen wrote:
>> On 01/19/2013 03:01 PM, Pali Rohár wrote:
>>> bq27xxx batteries have a lot of properties, more than
>>> power_supply interface. Some of them can be usefull for
>>> userspace applications (like CI bit) but does not make
>>> sense to add bq specified property to power_supply
>>> interface. When bq27x00_battery is not loaded userspace
>>> application (like i2cget) can use /dev/i2c-* interface for
>>> raw access. But when kernel module is attached to i2c
>>> device, userspace applications cannot access it via
>>> /dev/i2c-*.
>>
>> You can still access it if you use the I2C_SLAVE_FORCE flag.
>> This is a bit ugly, but I'd rather see an ugly hack in
>> userspace than in kernel space.
>>
> 
> What is I2C_SLAVE_FORCE flag doing? Isnt there some potential 
> hardware damage problems (like simultaneous access to i2c bus)?
> 

Well the transfers will still be serialized. I don't think this will cause
damage to the hardware.

- lars
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