Re: [PATCH UCC TDM 1/3 Updated] Platform changes for UCC TDM driverfor MPC8323eRDB. Also includes related QE changes and dts entries.

From: Timur Tabi
Date: Thu Jan 24 2008 - 10:56:28 EST


Anton Vorontsov wrote:

Can we not introduce new pio-maps in the device trees? There
were debates regarding this, and if I understood everything
correctly, pio-maps considered as a bad taste. Better
do bunch of par_io_config_pin() in the board file. Better
yet fixup the firmware (u-boot) to set up dedicated pins
correctly.

I'm on the fence with respect to pio-maps vs. par_io_config_pin() calls. The problem is that the configuration of these pins is board-specific, but pins are used by devices. A device driver can't call par_io_config_pin(), because the calls are different depending on which SoC and which UCC you're using. The platform code can't call par_io_config_pin(), because that configuration depends on which drivers are loaded.

In other words, the pin configurations are dependent on the UCC configurations, and the UCC configurations are stored in the device tree. So it makes sense to put the pin configurations in the device tree, too.

--
Timur Tabi
Linux kernel developer at Freescale
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