[coreboot-gerrit] Change in coreboot[master]: google/gru: enable the pull high for touchpad

[Caesar Wang (Code Review)]

Caesar Wang has uploaded a new change for review. ( https://review.coreboot.org/19863 )

Change subject: google/gru: enable the pull high for touchpad
......................................................................

google/gru: enable the pull high for touchpad

As the hardware designed on gru, the AP_I2C_TP_PU_EN (gpio3_b4) controlled
the SCL/SDA status to avoid leakage.

As the gpio3_b4 of rk3399 pull resistor is 26k~71k and 3.3v for supply
power, and gpio3_b4 pin connected 2.2k resistor to i2c of TP device.

The default of this gpio status is output high during the start to bootup,
it's very weak drive for the TP device that maybe cause to trigger the
recovery process of elan touchpad.

Also, the Elan updated their firmware to delay checking the i2c of
touchpad.

Change-Id: I9a67d1c041afafde24ed9f00716ba41a9b41a8da
Signed-off-by: Caesar Wang <wxt at rock-chips.com>
---
M src/mainboard/google/gru/romstage.c
1 file changed, 7 insertions(+), 0 deletions(-)


  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/63/19863/1

diff --git a/src/mainboard/google/gru/romstage.c b/src/mainboard/google/gru/romstage.c
index d644f7d..875cda0 100644
--- a/src/mainboard/google/gru/romstage.c
+++ b/src/mainboard/google/gru/romstage.c
@@ -67,12 +67,19 @@
 	reset_usb_otg1();
 }
 
+static void prepare_i2c(void)
+{
+       gpio_output(GPIO(3, B, 4), 1); /* Pull high for TP */
+}
+
 void main(void)
 {
 	console_init();
 	tsadc_init(TSHUT_POL_HIGH);
 	exception_init();
 
+	prepare_i2c();
+
 	/* Init DVS to conservative values. */
 	init_dvs_outputs();
 

-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I9a67d1c041afafde24ed9f00716ba41a9b41a8da
Gerrit-PatchSet: 1
Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-Owner: Caesar Wang <wxt at rock-chips.com>