[PATCH v3 2/2] firmware: Keem Bay: 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   | 46 +++++++++++++++++++
 1 file changed, 46 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..9adb8c87b788
--- /dev/null
+++ b/include/linux/firmware/intel/keembay_firmware.h
@@ -0,0 +1,46 @@
+/* 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 KEEMBAY_SET_SD_VOLTAGE_FUNC_ID	0x8200ff26
+#define KEEMBAY_SET_1V8_VOLT		0x01
+#define KEEMBAY_SET_3V3_VOLT		0x00
+
+#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC_DISCOVERY)
+static int do_fw_invoke(u64 func_id, u64 arg0, u64 arg1)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(func_id, arg0, arg1, &res);
+
+	return res.a0;
+}
+
+int keembay_sd_voltage_selection(int volt)
+{
+	return do_fw_invoke(KEEMBAY_SET_SD_VOLTAGE_FUNC_ID, volt, 0);
+}
+#else
+static inline int keembay_sd_voltage_selection(int volt)
+{
+	return -ENODEV;
+}
+#endif
+
+#endif /* __FIRMWARE_KEEMBAY_SMC_H__ */
-- 
2.17.1