Attention is currently required from: Eric Lai, Ivy Jian, Nick Vaccaro, Shelley Chen.
Karthik Ramasubramanian has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80300?usp=email )
Change subject: mb/google/brox: Initialize TCHSCR_RST_L/EN_PP3300_TCHSCR to 0 ......................................................................
Patch Set 2:
(1 comment)
File src/mainboard/google/brox/variants/baseboard/brox/devicetree.cb:
https://review.coreboot.org/c/coreboot/+/80300/comment/20e140fc_e6be0fab : PS2, Line 176: register "generic.detect" = "1"
Does this mean linux kernel has to probe for the touchscreen? That is not the direction we want to g […]
As per my discussion with EE team, there is no harm in probing the touchscreen in the firmware. EE team is concerned with two things: 1) Power sequencing 2) Touchscreen being on during suspend.
The right power sequencing is to enable the touchscreen before de-asserting the reset. Here is how it can be done
In romstage_gpio_table ``` /* GPP_F7 : [NF6: USB_C_GPP_F7] ==> EN_PP3300_TCHSCR */ PAD_CFG_GPO(GPP_F7, 1, PLTRST), /* GPP_F17 : [NF3: THC1_SPI2_RST# NF6: USB_C_GPP_F17] ==> TCHSCR_RST_L */ PAD_CFG_GPO(GPP_F17, 0, DEEP), ```
In ramstage_gpio_table ``` /* GPP_F7 : [NF6: USB_C_GPP_F7] ==> EN_PP3300_TCHSCR */ PAD_CFG_GPO(GPP_F7, 1, PLTRST), /* GPP_F17 : [NF3: THC1_SPI2_RST# NF6: USB_C_GPP_F17] ==> TCHSCR_RST_L */ PAD_CFG_GPO(GPP_F17, 1, DEEP), ```
Regarding touchscreen being on during S0ix, has_power_resource = 1 will add the required power resources in the ACPI table which will be used by OS to turn off the Touchscreen during suspend.