[PATCH v5 8/8] clk: fixed-rate: Convert into a module platform driver

[Ricardo Ribalda Delgado]

Adds support for fixed-rate clock providers which have not been
enabled via of_clk_init().

This is required by Device trees overlays that introduce clocks
providers.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.riba...@gmail.com>
---
 drivers/clk/clk-fixed-rate.c | 69 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 65 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/clk-fixed-rate.c b/drivers/clk/clk-fixed-rate.c
index 2edb39342a02..e64ba2315880 100644
--- a/drivers/clk/clk-fixed-rate.c
+++ b/drivers/clk/clk-fixed-rate.c
@@ -15,6 +15,7 @@
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/of.h>
+#include <linux/platform_device.h>
 
 /*
  * DOC: basic fixed-rate clock that cannot gate
@@ -160,15 +161,16 @@ EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate);
 /**
  * of_fixed_clk_setup() - Setup function for simple fixed rate clock
  */
-void of_fixed_clk_setup(struct device_node *node)
+struct clk *_of_fixed_clk_setup(struct device_node *node)
 {
        struct clk *clk;
        const char *clk_name = node->name;
        u32 rate;
        u32 accuracy = 0;
+       int ret;
 
        if (of_property_read_u32(node, "clock-frequency", &rate))
-               return;
+               return ERR_PTR(-EIO);
 
        of_property_read_u32(node, "clock-accuracy", &accuracy);
 
@@ -176,9 +178,68 @@ void of_fixed_clk_setup(struct device_node *node)
 
        clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL,
                                                    0, rate, accuracy);
-       if (!IS_ERR(clk))
-               of_clk_add_provider(node, of_clk_src_simple_get, clk);
+       if (IS_ERR(clk))
+               return clk;
+
+       ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+       if (ret) {
+               clk_unregister(clk);
+               return ERR_PTR(ret);
+       }
+
+       return clk;
+}
+
+void of_fixed_clk_setup(struct device_node *node)
+{
+       _of_fixed_clk_setup(node);
 }
 EXPORT_SYMBOL_GPL(of_fixed_clk_setup);
 CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);
+
+static int of_fixed_clk_remove(struct platform_device *pdev)
+{
+       struct clk *clk = platform_get_drvdata(pdev);
+
+       if (clk)
+               clk_unregister_fixed_rate(clk);
+
+       return 0;
+}
+
+static int of_fixed_clk_probe(struct platform_device *pdev)
+{
+       struct clk *clk;
+
+       /*
+        * This function is not executed when of_fixed_clk_setup
+        * succeeded.
+        */
+
+       clk = _of_fixed_clk_setup(pdev->dev.of_node);
+
+       if (IS_ERR(clk))
+               return PTR_ERR(clk);
+
+       platform_set_drvdata(pdev, clk);
+
+       return 0;
+}
+
+static const struct of_device_id of_fixed_clk_ids[] = {
+       { .compatible = "fixed-clock" },
+       { },
+};
+MODULE_DEVICE_TABLE(of, of_fixed_clk_ids);
+
+static struct platform_driver of_fixed_clk_driver = {
+       .driver = {
+               .name = "of_fixed_clk",
+               .of_match_table = of_fixed_clk_ids,
+       },
+       .probe = of_fixed_clk_probe,
+       .remove = of_fixed_clk_remove,
+};
+
+builtin_platform_driver(of_fixed_clk_driver);
 #endif
-- 
2.8.1