[PATCH v4 1/4] firmware: keembay: Add support for Arm Trusted Firmware Service call

[muhammad . husaini . zulkifli]

From: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@xxxxxxxxx>

Add header file to handle API function for device driver to communicate
with Arm Trusted Firmware.

Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@xxxxxxxxx>
---
 .../linux/firmware/intel/keembay_firmware.h   | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 include/linux/firmware/intel/keembay_firmware.h

diff --git a/include/linux/firmware/intel/keembay_firmware.h b/include/linux/firmware/intel/keembay_firmware.h
new file mode 100644
index 000000000000..8a62abcdfead
--- /dev/null
+++ b/include/linux/firmware/intel/keembay_firmware.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Intel Keembay SOC Firmware API Layer
+ *
+ *  Copyright (C) 2020-2021, Intel Corporation
+ *
+ *  Muhammad Husaini Zulkifli <Muhammad.Husaini.Zulkifli@xxxxxxxxx>
+ */
+
+#ifndef __FIRMWARE_KEEMBAY_SMC_H__
+#define __FIRMWARE_KEEMBAY_SMC_H__
+
+#include <linux/arm-smccc.h>
+
+/*
+ * This file defines API function that can be called by device driver in order to
+ * communicate with Arm Trusted Firmware.
+ */
+
+/* Setting for Keem Bay IO Pad Line Voltage Selection */
+#define ARM_SMCCC_SIP_KEEMBAY_SET_SD_VOLTAGE		\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,		\
+			   ARM_SMCCC_SMC_32,		\
+			   ARM_SMCCC_OWNER_SIP,		\
+			   0xFF26)
+
+#define KEEMBAY_SET_1V8_VOLT	1
+#define KEEMBAY_SET_3V3_VOLT	0
+
+#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC_DISCOVERY)
+static inline int keembay_sd_voltage_selection(int volt)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(ARM_SMCCC_SIP_KEEMBAY_SET_SD_VOLTAGE, volt, &res);
+	if ((int)res.a0 < 0)
+		return -EINVAL;
+
+	return 0;
+}
+#else
+static inline int keembay_sd_voltage_selection(int volt)
+{
+	return -ENODEV;
+}
+#endif
+#endif /* __FIRMWARE_KEEMBAY_SMC_H__ */
-- 
2.17.1