x86: apl: Add UART driver

Add a driver for the Apollo Lake UART. It uses the standard ns16550 device
but also sets up the input clock with LPSS and supports configuration via
of-platdata.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/x86/include/asm/arch-apollolake/uart.h b/arch/x86/include/asm/arch-apollolake/uart.h
new file mode 100644
index 0000000000..d4fffe6525
--- /dev/null
+++ b/arch/x86/include/asm/arch-apollolake/uart.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef _ASM_ARCH_UART_H
+#define _ASM_ARCH_UART_H
+
+/**
+ * apl_uart_init() - Set up the APL UART device and clock
+ *
+ * This enables the PCI device, sets up the MMIO region and turns on the clock
+ * using LPSS.
+ *
+ * The UART won't actually work unless the GPIO settings are correct and the
+ * signals actually exit the SoC. See board_debug_uart_init() for that.
+ */
+int apl_uart_init(pci_dev_t bdf, ulong base);
+
+#endif