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| author | Jan Dabros <jsd@semihalf.com> | 2021-04-15 23:47:04 +0200 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2021-04-22 14:15:38 +0000 |
| commit | 888e830480de3840ab11299a708267b97a339927 (patch) | |
| tree | fd02c4376257189b08a9be480589d62ccfead386 | |
| parent | a1d6eed22f8b364a9eed261eb6f165a7d22698af (diff) | |
| download | chrome-ec-888e830480de3840ab11299a708267b97a339927.tar.gz | |
gl3590: Add a delay to allow hub release i2c lines
GL3590 (USB3 hub) chip may drive I2C_SDA and I2C_SCL lines after being
released from reset. Max time for such "activities" is 200ms. In order
to ensure correct operations on the i2c bus, we need to delay all i2c
transactions in the system by such value.
Implementation is using hook with higher priority than I2C_INIT. This
guarantees that:
* SoC won't start i2c transactions before 200ms mark after GL3590's
RESETJ# pin deassertion;
* Original order of loading all generic modules (e.g. ioex_init,
board_init) won't need to be changed;
* Workaround applied only in platform-specific code.
BUG=b:181930164
BRANCH=main
TEST=build and flash new servo_v4p1 firmware
Plug in CHG and DUT cables. _Then_ plug in HOST cable and verify that
green diode is lit on servo_v4p1 board indicating proper pass-through
charging.
Signed-off-by: Jan Dabros <jsd@semihalf.com>
Change-Id: I32971d421eb541c788a87701ce5e8c62a8b35777
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2829770
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
| -rw-r--r-- | driver/gl3590.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/driver/gl3590.c b/driver/gl3590.c index 2a73f44aad..cb8d914d8c 100644 --- a/driver/gl3590.c +++ b/driver/gl3590.c @@ -4,6 +4,7 @@ */ #include "console.h" +#include "hooks.h" #include "i2c.h" #include "system.h" #include "util.h" @@ -11,6 +12,7 @@ #include "gl3590.h" +#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ## args) #define CPRINTF(format, args...) cprintf(CC_I2C, format, ## args) /* GL3590 is unique in terms of i2c_read, since it doesn't support repeated @@ -118,6 +120,19 @@ void gl3590_init(int hub) uhub_p->initialized = 1; } +/* + * GL3590 chip may drive I2C_SDA and I2C_SCL lines for 200ms (max) after it is + * released from reset (through gpio de-assertion in main()). In order to avoid + * broken I2C transactions, we need to add an extra delay before any activity on + * the I2C bus in the system. + */ +static void gl3590_delay_on_init(void) +{ + CPRINTS("Applying 200ms delay for GL3590 to release I2C lines"); + udelay(200 * MSEC); +} +DECLARE_HOOK(HOOK_INIT, gl3590_delay_on_init, HOOK_PRIO_INIT_I2C - 1); + void gl3590_irq_handler(int hub) { uint8_t buf = 0; |