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author | Lawrence R. Johnson <lrj@acm.org> | 2008-01-03 18:54:00 -0500 |
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committer | Stefan Roese <sr@denx.de> | 2008-01-04 11:38:45 +0100 |
commit | 5ab884b254ca2e707ab50545cd705f30108cf491 (patch) | |
tree | fa6a58b9ed000c496f2b4fc77f9605eaebcfe3b0 /lib_arm/div0.c | |
parent | 196404cdc1de495d6182e84731c200fc5748df15 (diff) | |
download | u-boot-imx-5ab884b254ca2e707ab50545cd705f30108cf491.zip u-boot-imx-5ab884b254ca2e707ab50545cd705f30108cf491.tar.gz u-boot-imx-5ab884b254ca2e707ab50545cd705f30108cf491.tar.bz2 |
ppc4xx: Add functionality to GPIO support
This patch makes two additions to GPIO support:
First, it adds function gpio_read_in_bit() to read the a bit from the
GPIO Input Register (GPIOx_IR) in the same way that function
gpio_read_out_bit() reads a bit from the GPIO Output Register
(GPIOx_OR).
Second, it modifies function gpio_set_chip_configuration() to provide
an additional option for configuring the GPIO from the
"CFG_4xx_GPIO_TABLE".
According to the 440EPx User's Manual, when an alternate output is used,
the three-state control is configured in one of two ways, depending on
the particular output. The first option is to select the corresponding
alternate three-state control in the GPIOx_TRSH/L registers. The second
option is to select the GPIO Three-State Control Register (GPIOx_TCR) in
the GPIOx_TRSH/L registers, and set the corresponding bit in the
GPIOx_TCR register to enable the output. For example, the Manual
specifies configuring the GPIO00 Alternate 1 Signal (PreAddr07) to use
the alternate three-state control (first option), and specifies
configuring the GPIO32 Alternate 1 Signal (USB2OM0) with the output
enabled in the GPIOx_TCR register (second option).
Currently, gpio_set_chip_configuration() configures all alternate signal
outputs to use the first option. This patch allow the second option to
be selected by setting the "out_val" element in the table entry to
"GPIO_OUT_1". The first option is used when the "out_val" element is
set to "GPIO_OUT_0". Because "out_val" is not currently used when an
alternate signal is selected, and because all current GPIO tables set
"out_val" to "GPIO_OUT_0" for all alternate signals, this patch should
not change any existing configurations.
Signed-off-by: Larry Johnson <lrj@acm.org>
Diffstat (limited to 'lib_arm/div0.c')
0 files changed, 0 insertions, 0 deletions