Change in coreboot[master]: mb/google/dedede/var/cret: Enable/disable LTE function based on FW_CO...

[Karthik Ramasubramanian (Code Review)]

Attention is currently required from: Furquan Shaikh, Dtrain Hsu, Henry Sun, Tim Wawrzynczak.
Karthik Ramasubramanian has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/54057 )

Change subject: mb/google/dedede/var/cret: Enable/disable LTE function based on FW_CONFIG
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Patch Set 1:

(4 comments)

Patchset:

PS1: 
@Furquan/Tim, Is it ok to enable fw_config in SMM stage? I am not sure if it was intentionally not enabled.

File src/lib/Makefile.inc:

https://review.coreboot.org/c/coreboot/+/54057/comment/a56594cb_2e666bdc 
PS1, Line 188: smm-$(CONFIG_FW_CONFIG) += fw_config.c
Please move it to a separate change of its own. Definitely needs to be checked with wider audience based on the use-case.

File src/mainboard/google/dedede/variants/cret/gpio.c:

https://review.coreboot.org/c/coreboot/+/54057/comment/56b7d4d5_6d1d74bd 
PS1, Line 122: 
Instead of maintaining 2 large tables, can you please check if this approach works for you keeping the original table?

static const struct pad_config lte_disable_pads = {
        PAD_NC(GPP_A10, NONE),
        PAD_NC(GPP_H17, NONE),
};

static void fw_config_handle(void *unused)
{
        if (!fw_config_probe(FW_CONFIG(LTE, LTE_PRESENT)))
                gpio_configure_pads(lte_disable_pads, ARRAY_SIZE(lte_disable_pads);
}
BOOT_STATE_INIT_ENTRY(BS_DEV_ENABLE, BS_ON_ENTRY, fw_config_handle, NULL);

File src/mainboard/google/dedede/variants/cret/overridetree.cb:

https://review.coreboot.org/c/coreboot/+/54057/comment/14a2e6dd_172eebf8 
PS1, Line 88: probe LTE LTE_PRESENT
Just want to remind that this works as long as you dont re-use the same USB port for a different use-case.