clk: gpio: Make into a platform driver

clk_get() for DT based clks already returns EPROBE_DEFER when the
OF clk provider is not present. So having all this code in the
clk provider to return EPROBE_DEFER when the gpio isn't ready yet
can be replaced with a platform driver that doesn't add the clk
provider until the gpio can be requested. Get rid of the
OF_CLK_DECLARE and convert this to a platform driver instead.

Tested-by: Jyri Sarha <jsarha@ti.com>
Cc: Sergej Sawazki <ce3a@gmx.de>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Jon Nettleton <jon@solid-run.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

1 files changed, 52 insertions, 113 deletions

diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
index cbbea2985cc9..fb32a7366ef6 100644
--- a/drivers/clk/clk-gpio.c
+++ b/drivers/clk/clk-gpio.c
@@ -20,6 +20,8 @@
 #include <linux/of_gpio.h>
 #include <linux/err.h>
 #include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
 
 /**
  * DOC: basic gpio gated clock which can be enabled and disabled
@@ -199,134 +201,71 @@ struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
 }
 EXPORT_SYMBOL_GPL(clk_register_gpio_mux);
 
-#ifdef CONFIG_OF
-/**
- * clk_register_get() has to be delayed, because -EPROBE_DEFER
- * can not be handled properly at of_clk_init() call time.
- */
-
-struct clk_gpio_delayed_register_data {
-        const char *gpio_name;
-        int num_parents;
-        const char **parent_names;
-        struct device_node *node;
-        struct mutex lock;
-        struct clk *clk;
-        struct clk *(*clk_register_get)(const char *name,
-                        const char * const *parent_names, u8 num_parents,
-                        unsigned gpio, bool active_low);
-};
-
-static struct clk *of_clk_gpio_delayed_register_get(
-                struct of_phandle_args *clkspec, void *_data)
+static int gpio_clk_driver_probe(struct platform_device *pdev)
 {
-        struct clk_gpio_delayed_register_data *data = _data;
-        struct clk *clk;
-        int gpio;
+        struct device_node *node = pdev->dev.of_node;
+        const char **parent_names, *gpio_name;
+        int num_parents, gpio;
         enum of_gpio_flags of_flags;
+        struct clk *clk;
+        bool active_low, is_mux;
+
+        num_parents = of_clk_get_parent_count(node);
+        if (num_parents < 0)
+                return -EINVAL;
 
-        mutex_lock(&data->lock);
+        if (num_parents) {
+                parent_names = devm_kcalloc(&pdev->dev, num_parents,
+                                            sizeof(char *), GFP_KERNEL);
+                if (!parent_names)
+                        return -ENOMEM;
 
-        if (data->clk) {
-                mutex_unlock(&data->lock);
-                return data->clk;
+                of_clk_parent_fill(node, parent_names, num_parents);
+        } else {
+                parent_names = NULL;
         }
 
-        gpio = of_get_named_gpio_flags(data->node, data->gpio_name, 0,
-                        &of_flags);
+        is_mux = of_device_is_compatible(node, "gpio-mux-clock");
+
+        gpio_name = is_mux ? "select-gpios" : "enable-gpios";
+        gpio = of_get_named_gpio_flags(node, gpio_name, 0, &of_flags);
         if (gpio < 0) {
-                mutex_unlock(&data->lock);
                 if (gpio == -EPROBE_DEFER)
                         pr_debug("%s: %s: GPIOs not yet available, retry later\n",
-                                        data->node->name, __func__);
+                                        node->name, __func__);
                 else
                         pr_err("%s: %s: Can't get '%s' DT property\n",
-                                        data->node->name, __func__,
-                                        data->gpio_name);
-                return ERR_PTR(gpio);
+                                        node->name, __func__,
+                                        gpio_name);
+                return gpio;
         }
 
-        clk = data->clk_register_get(data->node->name, data->parent_names,
-                        data->num_parents, gpio, of_flags & OF_GPIO_ACTIVE_LOW);
-        if (IS_ERR(clk))
-                goto out;
-
-        data->clk = clk;
-out:
-        mutex_unlock(&data->lock);
-
-        return clk;
-}
-
-static struct clk *of_clk_gpio_gate_delayed_register_get(const char *name,
-                const char * const *parent_names, u8 num_parents,
-                unsigned gpio, bool active_low)
-{
-        return clk_register_gpio_gate(NULL, name, parent_names ?
-                        parent_names[0] : NULL, gpio, active_low, 0);
-}
-
-static struct clk *of_clk_gpio_mux_delayed_register_get(const char *name,
-                const char * const *parent_names, u8 num_parents, unsigned gpio,
-                bool active_low)
-{
-        return clk_register_gpio_mux(NULL, name, parent_names, num_parents,
-                        gpio, active_low, 0);
-}
-
-static void __init of_gpio_clk_setup(struct device_node *node,
-                const char *gpio_name,
-                struct clk *(*clk_register_get)(const char *name,
-                                const char * const *parent_names,
-                                u8 num_parents,
-                                unsigned gpio, bool active_low))
-{
-        struct clk_gpio_delayed_register_data *data;
-        const char **parent_names;
-        int i, num_parents;
-
-        num_parents = of_clk_get_parent_count(node);
-        if (num_parents < 0)
-                return;
-
-        data = kzalloc(sizeof(*data), GFP_KERNEL);
-        if (!data)
-                return;
+        active_low = of_flags & OF_GPIO_ACTIVE_LOW;
 
-        if (num_parents) {
-                parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
-                if (!parent_names) {
-                        kfree(data);
-                        return;
-                }
-
-                for (i = 0; i < num_parents; i++)
-                        parent_names[i] = of_clk_get_parent_name(node, i);
-        } else {
-                parent_names = NULL;
-        }
-
-        data->num_parents = num_parents;
-        data->parent_names = parent_names;
-        data->node = node;
-        data->gpio_name = gpio_name;
-        data->clk_register_get = clk_register_get;
-        mutex_init(&data->lock);
+        if (is_mux)
+                clk = clk_register_gpio_mux(&pdev->dev, node->name,
+                                parent_names, num_parents, gpio, active_low, 0);
+        else
+                clk = clk_register_gpio_gate(&pdev->dev, node->name,
+                                parent_names ?  parent_names[0] : NULL, gpio,
+                                active_low, 0);
+        if (IS_ERR(clk))
+                return PTR_ERR(clk);
 
-        of_clk_add_provider(node, of_clk_gpio_delayed_register_get, data);
+        return of_clk_add_provider(node, of_clk_src_simple_get, clk);
 }
 
-static void __init of_gpio_gate_clk_setup(struct device_node *node)
-{
-        of_gpio_clk_setup(node, "enable-gpios",
-                of_clk_gpio_gate_delayed_register_get);
-}
-CLK_OF_DECLARE(gpio_gate_clk, "gpio-gate-clock", of_gpio_gate_clk_setup);
+static const struct of_device_id gpio_clk_match_table[] = {
+        { .compatible = "gpio-mux-clock" },
+        { .compatible = "gpio-gate-clock" },
+        { }
+};
 
-void __init of_gpio_mux_clk_setup(struct device_node *node)
-{
-        of_gpio_clk_setup(node, "select-gpios",
-                of_clk_gpio_mux_delayed_register_get);
-}
-CLK_OF_DECLARE(gpio_mux_clk, "gpio-mux-clock", of_gpio_mux_clk_setup);
-#endif
+static struct platform_driver gpio_clk_driver = {
+        .probe          = gpio_clk_driver_probe,
+        .driver         = {
+                .name   = "gpio-clk",
+                .of_match_table = gpio_clk_match_table,
+        },
+};
+builtin_platform_driver(gpio_clk_driver);