mb/google/dedede/var/metaknight: Add LTE power on/off sequence

LTE module used in metaknight has a specific power on/off sequence.
GPIOs related to power sequence are:
* GPP_A10 - LTE_PWR_OFF_R_ODL
* GPP_H17 - LTE_RESET_R_ODL
1. Power on: GPP_A10 -> 20ms -> GPP_H17
2. Power off: GPP_H17 -> 10ms -> GPP_A10
3. Warm reset: GPP_A10 keeps high, GPP_H17 goes low at least 2ms
Configure the GPIOs based on these requirements.

BUG=b:173671094
TEST=Build and boot Metaknight to OS. Ensure that the LTE module power
sequence requirements are met.

Change-Id: Ibff16129dfe2f1de2b1519049244aba4b3123e52
Signed-off-by: Tim Chen <tim-chen@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48195
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/mainboard/google/dedede/variants/metaknight/gpio.c b/src/mainboard/google/dedede/variants/metaknight/gpio.c
new file mode 100644
index 0000000000..d6a7fd599f
--- /dev/null
+++ b/src/mainboard/google/dedede/variants/metaknight/gpio.c
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <baseboard/gpio.h>
+#include <baseboard/variants.h>
+#include <commonlib/helpers.h>
+#include <vendorcode/google/chromeos/chromeos.h>
+
+/* Pad configuration in ramstage*/
+static const struct pad_config gpio_table[] = {
+	/* A10 : WWAN_EN => LTE_PWR_OFF_ODL */
+	PAD_CFG_GPO(GPP_A10, 1, PWROK),
+
+	/* H17 : WWAN_RST_L => LTE_RESET_R_ODL */
+	PAD_CFG_GPO(GPP_H17, 0, PLTRST),
+};
+
+const struct pad_config *variant_override_gpio_table(size_t *num)
+{
+	*num = ARRAY_SIZE(gpio_table);
+	return gpio_table;
+}