x86/platform/intel-mid: Add Power Management Unit driver

Add Power Management Unit driver to handle power states of South Complex
devices on Intel Tangier. In the future it might be expanded to cover North
Complex devices as well.

With this driver the power state of the host controllers such as SPI, I2C,
UART, eMMC, and DMA would be managed.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/1465928985-12113-1-git-send-email-andriy.shevchenko@linux.intel.com
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

drivers/pci/pci-mid.c

@@ -0,0 +1,77 @@
+/*
+ * Intel MID platform PM support
+ *
+ * Copyright (C) 2016, Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/pci.h>
+
+#include <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
+#include <asm/intel-mid.h>
+
+#include "pci.h"
+
+static bool mid_pci_power_manageable(struct pci_dev *dev)
+{
+	return true;
+}
+
+static int mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
+{
+	return intel_mid_pci_set_power_state(pdev, state);
+}
+
+static pci_power_t mid_pci_choose_state(struct pci_dev *pdev)
+{
+	return PCI_D3hot;
+}
+
+static int mid_pci_sleep_wake(struct pci_dev *dev, bool enable)
+{
+	return 0;
+}
+
+static int mid_pci_run_wake(struct pci_dev *dev, bool enable)
+{
+	return 0;
+}
+
+static bool mid_pci_need_resume(struct pci_dev *dev)
+{
+	return false;
+}
+
+static struct pci_platform_pm_ops mid_pci_platform_pm = {
+	.is_manageable	= mid_pci_power_manageable,
+	.set_state	= mid_pci_set_power_state,
+	.choose_state	= mid_pci_choose_state,
+	.sleep_wake	= mid_pci_sleep_wake,
+	.run_wake	= mid_pci_run_wake,
+	.need_resume	= mid_pci_need_resume,
+};
+
+#define ICPU(model)	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, }
+
+static const struct x86_cpu_id lpss_cpu_ids[] = {
+	ICPU(INTEL_FAM6_ATOM_MERRIFIELD1),
+	{}
+};
+
+static int __init mid_pci_init(void)
+{
+	const struct x86_cpu_id *id;
+
+	id = x86_match_cpu(lpss_cpu_ids);
+	if (id)
+		pci_set_platform_pm(&mid_pci_platform_pm);
+	return 0;
+}
+arch_initcall(mid_pci_init);