clk: x86: add support for Lynxpoint LPSS clocks

[firefly-linux-kernel-4.4.55.git] / drivers / clk / x86 / clk-lpss.c

diff --git a/drivers/clk/x86/clk-lpss.c b/drivers/clk/x86/clk-lpss.c
new file mode 100644 (file)
index 0000000..b5e229f
--- /dev/null
+++ b/drivers/clk/x86/clk-lpss.c
@@ -0,0 +1,99 @@
+/*
+ * Intel Low Power Subsystem clocks.
+ *
+ * Copyright (C) 2013, Intel Corporation
+ * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *         Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+
+static int clk_lpss_is_mmio_resource(struct acpi_resource *res, void *data)
+{
+       struct resource r;
+       return !acpi_dev_resource_memory(res, &r);
+}
+
+static acpi_status clk_lpss_find_mmio(acpi_handle handle, u32 level,
+                                     void *data, void **retval)
+{
+       struct resource_list_entry *rentry;
+       struct list_head resource_list;
+       struct acpi_device *adev;
+       const char *uid = data;
+       int ret;
+
+       if (acpi_bus_get_device(handle, &adev))
+               return AE_OK;
+
+       if (uid) {
+               if (!adev->pnp.unique_id)
+                       return AE_OK;
+               if (strcmp(uid, adev->pnp.unique_id))
+                       return AE_OK;
+       }
+
+       INIT_LIST_HEAD(&resource_list);
+       ret = acpi_dev_get_resources(adev, &resource_list,
+                                    clk_lpss_is_mmio_resource, NULL);
+       if (ret < 0)
+               return AE_NO_MEMORY;
+
+       list_for_each_entry(rentry, &resource_list, node)
+               if (resource_type(&rentry->res) == IORESOURCE_MEM) {
+                       *(struct resource *)retval = rentry->res;
+                       break;
+               }
+
+       acpi_dev_free_resource_list(&resource_list);
+       return AE_OK;
+}
+
+/**
+ * clk_register_lpss_gate - register LPSS clock gate
+ * @name: name of this clock gate
+ * @parent_name: parent clock name
+ * @hid: ACPI _HID of the device
+ * @uid: ACPI _UID of the device (optional)
+ * @offset: LPSS PRV_CLOCK_PARAMS offset
+ *
+ * Creates and registers LPSS clock gate.
+ */
+struct clk *clk_register_lpss_gate(const char *name, const char *parent_name,
+                                  const char *hid, const char *uid,
+                                  unsigned offset)
+{
+       struct resource res = { };
+       void __iomem *mmio_base;
+       acpi_status status;
+       struct clk *clk;
+
+       /*
+        * First try to look the device and its mmio resource from the
+        * ACPI namespace.
+        */
+       status = acpi_get_devices(hid, clk_lpss_find_mmio, (void *)uid,
+                                 (void **)&res);
+       if (ACPI_FAILURE(status) || !res.start)
+               return ERR_PTR(-ENODEV);
+
+       mmio_base = ioremap(res.start, resource_size(&res));
+       if (!mmio_base)
+               return ERR_PTR(-ENOMEM);
+
+       clk = clk_register_gate(NULL, name, parent_name, 0, mmio_base + offset,
+                               0, 0, NULL);
+       if (IS_ERR(clk))
+               iounmap(mmio_base);
+
+       return clk;
+}