diff options
| author | Bhanu Prakash Maiya <bhanumaiya@chromium.org> | 2022-12-27 12:32:22 -0700 |
|---|---|---|
| committer | Tzung-Bi Shih <tzungbi@kernel.org> | 2022-12-28 11:41:48 +0800 |
| commit | 04a8bdd135cc05b10b665cedb360c7353312602d (patch) | |
| tree | 87bb5248d135a61346c2318b032f29e447380f40 /drivers/platform/chrome/Kconfig | |
| parent | b251c0e7ea5ddfab21495c36cd3c3fa90c36f104 (diff) | |
platform/chrome: cros_ec_uart: Add transport layer
This patch does following:
1. Adds a new cros-ec-uart driver. This driver can send EC requests on
UART and process response packets received on UART transport.
2. Once probed, this driver will initialize the serdev device based on
the underlying information in the ACPI resource. After serdev device
properties are set, this driver will register itself cros-ec.
3. High level driver can use this implementation to talk to ChromeOS
Embedded Controller device in case it supports UART as transport.
4. When cros-ec driver initiates a request packet, outgoing message is
processed in buffer and sent via serdev. Once bytes are sent, driver
enables a wait_queue.
5. Since ChromeOS EC device sends response asynchronously, AP's TTY
driver accumulates response bytes and calls the registered callback.
TTY driver can send multiple callback for bytes ranging from 1 to MAX
bytes supported by EC device.
6. Driver waits for EC_MSG_DEADLINE_MS to collect and process received
bytes. It wakes wait_queue if expected bytes are received or else
wait_queue timeout. Based on the error condition, driver returns
data_len or error to cros_ec.
Signed-off-by: Bhanu Prakash Maiya <bhanumaiya@chromium.org>
Co-developed-by: Mark Hasemeyer <markhas@chromium.org>
Signed-off-by: Mark Hasemeyer <markhas@chromium.org>
Reviewed-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20221227123212.v13.1.If7926fcbad397bc6990dd725690229bed403948c@changeid
Diffstat (limited to 'drivers/platform/chrome/Kconfig')
| -rw-r--r-- | drivers/platform/chrome/Kconfig | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index c1ca247987d2..0d272c87f32b 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -119,6 +119,16 @@ config CROS_EC_SPI response time cannot be guaranteed, we support ignoring 'pre-amble' bytes before the response actually starts. +config CROS_EC_UART + tristate "ChromeOS Embedded Controller (UART)" + depends on CROS_EC && ACPI && SERIAL_DEV_BUS + help + If you say Y here, you get support for talking to the ChromeOS EC + through a UART, using a byte-level protocol. + + To compile this driver as a module, choose M here: the + module will be called cros_ec_uart. + config CROS_EC_LPC tristate "ChromeOS Embedded Controller (LPC)" depends on CROS_EC && ACPI && (X86 || COMPILE_TEST) |