x86: Add low-power subsystem (lpss) support

This subsystem is present on various Intel SoCs.

Add very basic support for taking an lpss device out of reset.

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

1 files changed, 36 insertions, 0 deletions

diff --git a/arch/x86/include/asm/lpss.h b/arch/x86/include/asm/lpss.h
new file mode 100644
index 0000000000..7814872688
--- /dev/null
+++ b/arch/x86/include/asm/lpss.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef __ASM_LPSS_H
+#define __ASM_LPSS_H
+
+struct udevice;
+
+/* D0 and D3 enable config */
+enum lpss_pwr_state {
+	STATE_D0 = 0,
+	STATE_D3 = 3
+};
+
+/**
+ * lpss_reset_release() - Release device from reset
+ *
+ * This is used for devices which have LPSS support.
+ *
+ * @regs: Pointer to device registers
+ */
+void lpss_reset_release(void *regs);
+
+/**
+ * lpss_set_power_state() - Change power state of a device
+ *
+ * This is used for devices which have LPSS support.
+ *
+ * @dev: Device to update
+ * @state: New power state to set
+ */
+void lpss_set_power_state(struct udevice *dev, enum lpss_pwr_state state);
+
+#endif