diff options
| author | Enric Balletbo i Serra <enric.balletbo@collabora.com> | 2019-06-14 23:43:01 +0200 |
|---|---|---|
| committer | Enric Balletbo i Serra <enric.balletbo@collabora.com> | 2019-06-20 12:00:32 +0200 |
| commit | 22c040fa21b604b9b3d88645e108fb2f0a74474b (patch) | |
| tree | f03e0f4c4be98c4f1ad2f8c680ec2af9c813c9de /drivers/platform/chrome/Kconfig | |
| parent | 4116fd25c5262e90427f9840e861a8553374a867 (diff) | |
platform/chrome: cros_ec_lpc: Choose Microchip EC at runtime
On many boards, communication between the kernel and the Embedded
Controller happens over an LPC bus. In these cases, the kernel config
CONFIG_CROS_EC_LPC is enabled. Some of these LPC boards contain a
Microchip Embedded Controller (MEC) that is different from the regular
EC. On these devices, the same LPC bus is used, but the protocol is
a little different. In these cases, the CONFIG_CROS_EC_LPC_MEC kernel
config is enabled. Currently, the kernel decides at compile-time whether
or not to use the MEC variant, and, when that kernel option is selected
it breaks the other boards. We would like a kind of runtime detection to
avoid this.
This patch adds that detection mechanism by probing the protocol at
runtime, first we assume that a MEC variant is connected, and if the
protocol fails it fallbacks to the regular EC. This adds a bit of
overload because we try to read twice on those LPC boards that doesn't
contain a MEC variant, but is a better solution than having to select the
EC variant at compile-time.
While here also fix the alignment in Kconfig file for this config option
replacing the spaces by tabs.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Nick Crews <ncrews@chromium.org>
Reviewed-by: Nick Crews <ncrews@chromium.org>
Diffstat (limited to 'drivers/platform/chrome/Kconfig')
| -rw-r--r-- | drivers/platform/chrome/Kconfig | 29 |
1 files changed, 9 insertions, 20 deletions
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index 0b3c2b9ffd2f..8010e7e395ce 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -95,28 +95,17 @@ config CROS_EC_SPI 'pre-amble' bytes before the response actually starts. config CROS_EC_LPC - tristate "ChromeOS Embedded Controller (LPC)" - depends on MFD_CROS_EC && ACPI && (X86 || COMPILE_TEST) - help - If you say Y here, you get support for talking to the ChromeOS EC - over an LPC bus. This uses a simple byte-level protocol with a - checksum. This is used for userspace access only. The kernel - typically has its own communication methods. - - To compile this driver as a module, choose M here: the - module will be called cros_ec_lpc. - -config CROS_EC_LPC_MEC - bool "ChromeOS Embedded Controller LPC Microchip EC (MEC) variant" - depends on CROS_EC_LPC - default n + tristate "ChromeOS Embedded Controller (LPC)" + depends on MFD_CROS_EC && ACPI && (X86 || COMPILE_TEST) help - If you say Y here, a variant LPC protocol for the Microchip EC - will be used. Note that this variant is not backward compatible - with non-Microchip ECs. + If you say Y here, you get support for talking to the ChromeOS EC + over an LPC bus, including the LPC Microchip EC (MEC) variant. + This uses a simple byte-level protocol with a checksum. This is + used for userspace access only. The kernel typically has its own + communication methods. - If you have a ChromeOS Embedded Controller Microchip EC variant - choose Y here. + To compile this driver as a module, choose M here: the + module will be called cros_ec_lpcs. config CROS_EC_PROTO bool |