1 files changed, 101 insertions, 0 deletions

diff --git a/drivers/clk/clk-fixed-mmio.c b/drivers/clk/clk-fixed-mmio.c
new file mode 100644
index 000000000000..d1a97d971183
--- /dev/null
+++ b/drivers/clk/clk-fixed-mmio.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Memory Mapped IO Fixed clock driver
+ *
+ * Copyright (C) 2018 Cadence Design Systems, Inc.
+ *
+ * Authors:
+ *      Jan Kotas <jank@cadence.com>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/of_address.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+static struct clk_hw *fixed_mmio_clk_setup(struct device_node *node)
+{
+        struct clk_hw *clk;
+        const char *clk_name = node->name;
+        void __iomem *base;
+        u32 freq;
+        int ret;
+
+        base = of_iomap(node, 0);
+        if (!base) {
+                pr_err("%pOFn: failed to map address\n", node);
+                return ERR_PTR(-EIO);
+        }
+
+        freq = readl(base);
+        iounmap(base);
+        of_property_read_string(node, "clock-output-names", &clk_name);
+
+        clk = clk_hw_register_fixed_rate(NULL, clk_name, NULL, 0, freq);
+        if (IS_ERR(clk)) {
+                pr_err("%pOFn: failed to register fixed rate clock\n", node);
+                return clk;
+        }
+
+        ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, clk);
+        if (ret) {
+                pr_err("%pOFn: failed to add clock provider\n", node);
+                clk_hw_unregister(clk);
+                clk = ERR_PTR(ret);
+        }
+
+        return clk;
+}
+
+static void __init of_fixed_mmio_clk_setup(struct device_node *node)
+{
+        fixed_mmio_clk_setup(node);
+}
+CLK_OF_DECLARE(fixed_mmio_clk, "fixed-mmio-clock", of_fixed_mmio_clk_setup);
+
+/**
+ * This is not executed when of_fixed_mmio_clk_setup succeeded.
+ */
+static int of_fixed_mmio_clk_probe(struct platform_device *pdev)
+{
+        struct clk_hw *clk;
+
+        clk = fixed_mmio_clk_setup(pdev->dev.of_node);
+        if (IS_ERR(clk))
+                return PTR_ERR(clk);
+
+        platform_set_drvdata(pdev, clk);
+
+        return 0;
+}
+
+static int of_fixed_mmio_clk_remove(struct platform_device *pdev)
+{
+        struct clk_hw *clk = platform_get_drvdata(pdev);
+
+        of_clk_del_provider(pdev->dev.of_node);
+        clk_hw_unregister_fixed_rate(clk);
+
+        return 0;
+}
+
+static const struct of_device_id of_fixed_mmio_clk_ids[] = {
+        { .compatible = "fixed-mmio-clock" },
+        { }
+};
+MODULE_DEVICE_TABLE(of, of_fixed_mmio_clk_ids);
+
+static struct platform_driver of_fixed_mmio_clk_driver = {
+        .driver = {
+                .name = "of_fixed_mmio_clk",
+                .of_match_table = of_fixed_mmio_clk_ids,
+        },
+        .probe = of_fixed_mmio_clk_probe,
+        .remove = of_fixed_mmio_clk_remove,
+};
+module_platform_driver(of_fixed_mmio_clk_driver);
+
+MODULE_AUTHOR("Jan Kotas <jank@cadence.com>");
+MODULE_DESCRIPTION("Memory Mapped IO Fixed clock driver");
+MODULE_LICENSE("GPL v2");