soc/amd/*/bootblock,early_fch: rework i2c_scl_pins configuration

drive_scl in soc/amd/common/block/i2c/i2c.c writes the raw GPIO MMIO
configuration register and drives it as output, so don't initially
configure the GPIO as input with no pull up/down. This is a preparation
to use the common AMD GPIO access functions instead of the raw register
accesses, since the gpio_set function only sets the output value, but
doesn't reconfigure the direction. Using gpio_output there instead would
reconfigure the direction as well, but would result in doubling the
number of MMIO accesses, so just configure the GPIOs correctly right
away to avoid that.

TEST=The waveform on the SCL pin of I2C3 on a barla/careena Chromebook
looks exactly the same as before during the reset_i2c_peripherals call.
This was probed at the SCL pad of the unpopulated I2C level shifter on
the side that is connected to the SoC.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I8e94afe0c755a02abcc722d5094e220d8781f8f5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56807
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 13 insertions, 13 deletions

diff --git a/src/soc/amd/cezanne/early_fch.c b/src/soc/amd/cezanne/early_fch.c
index 16a8a53c75..cdb871b916 100644
--- a/src/soc/amd/cezanne/early_fch.c
+++ b/src/soc/amd/cezanne/early_fch.c
@@ -13,12 +13,12 @@
 
 #include "chip.h"
 
-/* This table is for the initial conversion of all SCL pins to input with no pull. */
+/* Table to switch SCL pins to outputs to initially reset the I2C peripherals */
 static const struct soc_i2c_scl_pin i2c_scl_pins[] = {
-	{ PAD_GPI(I2C0_SCL_PIN, PULL_NONE), GPIO_I2C0_SCL },
-	{ PAD_GPI(I2C1_SCL_PIN, PULL_NONE), GPIO_I2C1_SCL },
-	{ PAD_GPI(I2C2_SCL_PIN, PULL_NONE), GPIO_I2C2_SCL },
-	{ PAD_GPI(I2C3_SCL_PIN, PULL_NONE), GPIO_I2C3_SCL },
+	{ PAD_GPO(I2C0_SCL_PIN, HIGH), GPIO_I2C0_SCL },
+	{ PAD_GPO(I2C1_SCL_PIN, HIGH), GPIO_I2C1_SCL },
+	{ PAD_GPO(I2C2_SCL_PIN, HIGH), GPIO_I2C2_SCL },
+	{ PAD_GPO(I2C3_SCL_PIN, HIGH), GPIO_I2C3_SCL },
 };
 
 static void reset_i2c_peripherals(void)
diff --git a/src/soc/amd/picasso/early_fch.c b/src/soc/amd/picasso/early_fch.c
index 110718e2e1..048ce12819 100644
--- a/src/soc/amd/picasso/early_fch.c
+++ b/src/soc/amd/picasso/early_fch.c
@@ -15,10 +15,10 @@
 
 #include "chip.h"
 
-/* This table is for the initial conversion of all SCL pins to input with no pull. */
+/* Table to switch SCL pins to outputs to initially reset the I2C peripherals */
 static const struct soc_i2c_scl_pin i2c_scl_pins[] = {
-	{ PAD_GPI(I2C2_SCL_PIN, PULL_NONE), GPIO_I2C2_SCL },
-	{ PAD_GPI(I2C3_SCL_PIN, PULL_NONE), GPIO_I2C3_SCL },
+	{ PAD_GPO(I2C2_SCL_PIN, HIGH), GPIO_I2C2_SCL },
+	{ PAD_GPO(I2C3_SCL_PIN, HIGH), GPIO_I2C3_SCL },
 	/* I2C4 is a peripheral device only */
 };
 
diff --git a/src/soc/amd/stoneyridge/bootblock.c b/src/soc/amd/stoneyridge/bootblock.c
index fc4284f502..499ff633d4 100644
--- a/src/soc/amd/stoneyridge/bootblock.c
+++ b/src/soc/amd/stoneyridge/bootblock.c
@@ -28,12 +28,12 @@
 #error "Error: CONFIG_PI_AGESA_CAR_HEAP_BASE must be >= 1MB"
 #endif
 
-/* This table is for the initial conversion of all SCL pins to input with no pull. */
+/* Table to switch SCL pins to outputs to initially reset the I2C peripherals */
 static const struct soc_i2c_scl_pin i2c_scl_pins[] = {
-	{ PAD_GPI(I2C0_SCL_PIN, PULL_NONE), GPIO_I2C0_SCL },
-	{ PAD_GPI(I2C1_SCL_PIN, PULL_NONE), GPIO_I2C1_SCL },
-	{ PAD_GPI(I2C2_SCL_PIN, PULL_NONE), GPIO_I2C2_SCL },
-	{ PAD_GPI(I2C3_SCL_PIN, PULL_NONE), GPIO_I2C3_SCL },
+	{ PAD_GPO(I2C0_SCL_PIN, HIGH), GPIO_I2C0_SCL },
+	{ PAD_GPO(I2C1_SCL_PIN, HIGH), GPIO_I2C1_SCL },
+	{ PAD_GPO(I2C2_SCL_PIN, HIGH), GPIO_I2C2_SCL },
+	{ PAD_GPO(I2C3_SCL_PIN, HIGH), GPIO_I2C3_SCL },
 };
 
 /* Set the MMIO Configuration Base Address, Bus Range, and misc MTRRs. */