platform/x86: Add Elkhart Lake SCU/PMC support

Intel Elkhart Lake exposes SCU/PMC as an ACPI device that only supports
IPC functionality so add a platform driver supporting it. Interrupt is
optional so we let intel_scu_ipc_probe() to decide based on the passed
platform data whether it uses interrupt or polling.

Co-developed-by: Divya Sasidharan <divya.s.sasidharan@intel.com>
Signed-off-by: Divya Sasidharan <divya.s.sasidharan@intel.com>
Co-developed-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/Kconfig

@@ -1356,6 +1356,15 @@ config INTEL_SCU_PCI
 	    Broxton
 	    Apollo Lake
 
+config INTEL_SCU_PLATFORM
+	tristate "Intel SCU platform driver"
+	depends on ACPI
+	select INTEL_SCU
+	help
+	  This driver is used to bridge the communications between kernel
+	  and SCU (sometimes called PMC as well). The driver currently
+	  supports Intel Elkhart Lake and compatible platforms.
+
 config INTEL_SCU_IPC_UTIL
 	tristate "Intel SCU IPC utility driver"
 	depends on INTEL_SCU

drivers/platform/x86/Makefile

@@ -141,6 +141,7 @@ obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core.o intel_pmc_core_pltdrv.o
 obj-$(CONFIG_INTEL_PUNIT_IPC)		+= intel_punit_ipc.o
 obj-$(CONFIG_INTEL_SCU_IPC)		+= intel_scu_ipc.o
 obj-$(CONFIG_INTEL_SCU_PCI)		+= intel_scu_pcidrv.o
+obj-$(CONFIG_INTEL_SCU_PLATFORM)	+= intel_scu_pltdrv.o
 obj-$(CONFIG_INTEL_SCU_IPC_UTIL)	+= intel_scu_ipcutil.o
 obj-$(CONFIG_INTEL_TELEMETRY)		+= intel_telemetry_core.o \
 					   intel_telemetry_pltdrv.o \

drivers/platform/x86/intel_scu_pltdrv.c

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Platform driver for the Intel SCU.
+ *
+ * Copyright (C) 2019, Intel Corporation
+ * Authors: Divya Sasidharan <divya.s.sasidharan@intel.com>
+ *	    Mika Westerberg <mika.westerberg@linux.intel.com>
+ *	    Rajmohan Mani <rajmohan.mani@intel.com>
+ */
+
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <asm/intel_scu_ipc.h>
+
+static int intel_scu_platform_probe(struct platform_device *pdev)
+{
+	struct intel_scu_ipc_data scu_data = {};
+	struct intel_scu_ipc_dev *scu;
+	const struct resource *res;
+
+	scu_data.irq = platform_get_irq_optional(pdev, 0);
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENOMEM;
+
+	scu_data.mem = *res;
+
+	scu = devm_intel_scu_ipc_register(&pdev->dev, &scu_data);
+	if (IS_ERR(scu))
+		return PTR_ERR(scu);
+
+	platform_set_drvdata(pdev, scu);
+	return 0;
+}
+
+static const struct acpi_device_id intel_scu_acpi_ids[] = {
+	{ "INTC1026" },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, intel_scu_acpi_ids);
+
+static struct platform_driver intel_scu_platform_driver = {
+	.probe = intel_scu_platform_probe,
+	.driver = {
+		.name = "intel_scu",
+		.acpi_match_table = intel_scu_acpi_ids,
+	},
+};
+module_platform_driver(intel_scu_platform_driver);
+
+MODULE_AUTHOR("Divya Sasidharan <divya.s.sasidharan@intel.com>");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com");
+MODULE_AUTHOR("Rajmohan Mani <rajmohan.mani@intel.com>");
+MODULE_DESCRIPTION("Intel SCU platform driver");
+MODULE_LICENSE("GPL v2");