Subject: Sleep-capable GPIO slave-selects on MPC52xx?

From: Bill Gatliff <[email-masked]>
Date: Mon, 11 Jan 2010 14:13:31 -0600

Guys:

A platform I have inherited utilizes a GPIO on an I2C expander chip
(MAX7314) as a SPI slave-select.  I'm using the actual MPC52xx SPI
peripheral, not a PSC.

It looks like the current version of the MPC52xx SPI driver won't work
with sleep-capable GPIOs for slave-selects.  In particular, it looks
like mpc52xx_spi_fsmstate_transfer() is an interrupt handler that calls
mpc52xx_spi_chipsel(), which itself calls gpio_set_value().  Or, at
least my kernel thinks so, since I get a barrage of oops-type output
screaming at me whenever I hit the SPI device.  :)

Am I missing something, or is this a known (or at least now-identified)
limitation of the current mpc52xx_spi.c?

Thanks!

b.g.

-- 
Bill Gatliff
Embedded systems training and consulting
http://billgatliff.com
[email-masked]