|author||Caveh Jalali <firstname.lastname@example.org>||Tue Jul 31 19:30:11 2018 -0700|
|committer||Patrick Georgi <email@example.com>||Fri Nov 16 10:02:37 2018 +0000|
mb/google/poppy/variant/atlas: I2C: run trackpad at 1MHz With this change, coreboot thinks we're running at 1MHz: DW I2C bus 2 at 0xd1133000 (1000 KHz) Elan eKT3644 IC Specification (trackpad) requires: Low Time larger than 500ns (61 * 8.3ns = 506ns). High Time larger than 260ns (32 * 8.3ns = 265ns), Data Hold_time larger than 0ns. Start Condition Hold time larger than 250ns. Rise/Fall time of less than 120ns. HCNT controls both High Time and Start Condition Hold time. LCNT controls Low Time. SDA_HOLD controls Data Hold Time. P2 Atlas "Rise time" is 90ns and "Fall time" is 32ns and tuned using resistors on the board and must be considered when adjusting any of the parameters since these times are all measured at 30 or 70% of base and peak voltages (0v/1.8v). The eKT3644 requirements are met with LCNT=69, HCNT=33, SDA_HOLD=20 which yields the SCL at around 950KHz - suboptimal but compliant. Lower LCNT or HCNT results in "lost arbitration" errors or not complying with eKT3644 requirements. Verified by firstname.lastname@example.org. Scope shots posted here: https://b.corp.google.com/issues/78601949#comment177 BUG=b:78601949 BRANCH=none TEST=Farzam provided test points on track pad for SCL/SDA/GND. Waveforms measured with oscilloscope and screen shots attached to bug (comment #177, #155, #100). Operate trackpad/touchscreen Review dmesg (kernel) output for correct speed, parameters, and no errors (e.g. "lost arbitration" or "host controller timeout") Change-Id: Iaf42ba7b8818b7cd9c8dcc657823dac705659d38 Signed-off-by: Caveh Jalali <email@example.com> Signed-off-by: Grant Grundler <firstname.lastname@example.org> Tested-by: email@example.com Tested-by: firstname.lastname@example.org Reviewed-on: https://review.coreboot.org/29553 Tested-by: build bot (Jenkins) <email@example.com> Reviewed-by: Caveh Jalali <firstname.lastname@example.org> Reviewed-by: Furquan Shaikh <email@example.com> Reviewed-by: Gaggery Tsai <firstname.lastname@example.org>
coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.
With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.
coreboot was formerly known as LinuxBIOS.
After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.
See https://www.coreboot.org/Payloads for a list of supported payloads.
coreboot supports a wide range of chipsets, devices, and mainboards.
For details please consult:
ANY_TOOLCHAINKconfig option if you're feeling lucky (no support in this case).
Please consult https://www.coreboot.org/Build_HOWTO for details.
If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.
Please see https://www.coreboot.org/QEMU for details.
Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:
You can contact us directly on the coreboot mailing list:
The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.
coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.
This makes the resulting coreboot images licensed under the GPL, version 2.