[U-Boot] [PATCH] ARM: tegra: rm Jetson TK1 PMIC GPIO programming

Thierry Reding thierry.reding at gmail.com
Fri Jan 22 16:52:44 CET 2016


On Mon, Jan 18, 2016 at 11:23:16AM -0700, Stephen Warren wrote:
> From: Stephen Warren <swarren at nvidia.com>
> 
> The PMIC is configured such that its GPIOs have the correct configuration
> at power-up, so no programming is required.
> 
> In fact, the current programming is actively wrong, since:
> 
> (a) the AS3722 driver configures the GPIO to be an output before setting
> its output value, which causes a 0v glitch on the output.
> 
> (b) the AS3722 driver configures the GPIO to drive a high voltage from its
> VSUP_GPIO power source rather than its VDD_GPIO_LV power source, so the pin
> drives 5V not 1.8V as desired.
> 
> Solve these problems by removing the code which configures the PMIC GPIOs.
> 
> Note that this patch was tested directly on top of v2016.01; since then,
> commit 96350f729c42 "dm: tegra: net: Convert tegra boards to driver model
> for Ethernet" prevents PCIe from being initialized. Alternatively, simply
> revert that commit to get PCIe Ethernet working again, then apply this
> patch to test.
> 
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
>  board/nvidia/jetson-tk1/jetson-tk1.c | 13 -------------
>  1 file changed, 13 deletions(-)

After applying your other patch:

	pci: restore initialization for DM_PCI

to restore PCI networking on Jetson TK1 I was able to verify that this
still works for me. Interestingly the code before seems to trigger a
visual glitch in the serial output, though I'm not sure I had seen one
like that back when I initially added this support.

Either way, this patch:

Tested-by: Thierry Reding <treding at nvidia.com>
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