Re: [PATCH v4 01/11] mfd: add pruss mfd driver.

From: Subhasish Ghosh
Date: Tue May 10 2011 - 05:53:12 EST


Instead of passing a configuration file into the MFD driver and
calling it a firmware, I can see three other options that I believe
would be nicer:

1. have a single firmware blob that describes the child devices
and the code that is to be loaded into both units. If they are
acting as one device, either make sure you only create one
child node, or create one with a name that no driver binds to.

2. Call request_firmware separately for the two child devices,
and configure them separately based on the information in the
firmware files. In the case where they should act as a single
device, call the children e.g. "pruss-uart-a" and "pruss-uart-b",
then bind to both names in the pruss-uart drivers and only
start using the device when you have both nodes for the same
parent.

3. Do the configuration through sysfs files in the MFD device node,
which then cause the creation of the child devices. This means you
need extra user space scripts to write the addititonal files, but
is also the most flexible way.


Are you suggesting something like:

/sys..../pruss/pru0/id
/sys..../pruss/pru0/fw_name
/sys..../pruss/pru0/load

/sys..../pruss/pru1/id
/sys..../pruss/pru1/fw_name
/sys..../pruss/pru1/load

I can program these configs and store them in the pru private.
Then write something into load.
This can load the PRU based upon the configs.
But, I am not sure how to do this effectively using sysfs,
I mean I don't want to end up writing six write and six read
handlers. --
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