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path: root/src/drivers/uart/acpi
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2020-07-02acpi_device: Replace polarity with active_low in acpi_gpio for GpioIoFurquan Shaikh
As per ACPI spec, GpioIo does not have any polarity associated with it. Linux kernel uses `active_low` argument within GPIO _DSD property to allow BIOS to indicate if the corresponding GPIO should be treated as active low. Thus, if GPIO has active high polarity or if it does not have any polarity associated with it, then the `active_low` argument is supposed to be set to 0. Having a `polarity` field in acpi_gpio seems confusing because GPIOs might not always have polarity associated with them. Example, in case of DMIC-select GPIO where 0 means select DMIC0 and 1 means select DMIC1, there is no polarity associated with the GPIO. Thus, it would be clearer for mainboard to use macros without having to specify a particular polarity. In order to enable mainboards to provide GPIO information without polarity for GpioIo usage, this change also adds `ACPI_GPIO_OUTPUT` and `ACPI_GPIO_INPUT` macros. BUG=b:157603026 Change-Id: I39d2a6ac8f149a74afeb915812fece86c9b9ad93 Signed-off-by: Furquan Shaikh <furquan@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/42968 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2020-06-04drivers/uart/acpi: Add new device driver for UART attached devicesDuncan Laurie
This driver generates an ACPI device object for a UART attached device with all of the expected device support handlers like different interrupt sources and power control GPIOs. Example use: chip drivers/uart/acpi register "name" = ""UDEV"" register "desc" = ""UART Attached Device"" register "hid" = "ACPI_DT_NAMESPACE_HID" register "compat_string" = ""google,cros-ec-uart"" register "irq_gpio" = "ACPI_GPIO_IRQ_LEVEL_LOW_WAKE(GPP_C20)" register "uart" = "ACPI_UART_RAW_DEVICE(115200, 64)" device generic 0 on end end Resulting in this ACPI device: Device (UDEV) { Name (_HID, "PRP0001") Name (_UID, Zero) Name (_DDN, "UART Attached Device") Method (_STA, 0, NotSerialized) { Return (0x0F) } Name (_CRS, ResourceTemplate () { UartSerialBusV2 (0x0001C200, DataBitsEight, StopBitsOne, 0x00, LittleEndian, ParityTypeNone, FlowControlNone, 0x0040, 0x0040, "\\_SB.PCI0.UAR2", 0x00, ResourceConsumer, , Exclusive) GpioInt (Level, ActiveLow, ExclusiveAndWake, PullDefault, 0x0000, "\\_SB.PCI0.GPIO", 0x00, ResourceConsumer) { 0x0114 } }) Name (_DSD, Package (0x02) { ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package (0x01) { Package (0x02) { "compatible", "google,cros-ec-uart" } } }) } Change-Id: Idfd2d9d2ab6990a82ddd401734c0d9b1b0b8f82d Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/41793 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Furquan Shaikh <furquan@google.com> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>