clk: generalize devm_clk_get() a bit

Allow to add an exit hook to devm managed clocks. Also use
clk_get_optional() in devm_clk_get_optional instead of open coding it.
The generalisation will be used in the next commit to add some more
devm_clk helpers.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <aardelean@deviqon.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220520075737.758761-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: Uwe Kleine-König

drivers/clk/clk-devres.c

@@ -4,39 +4,71 @@
 #include <linux/export.h>
 #include <linux/gfp.h>
 
+struct devm_clk_state {
+	struct clk *clk;
+	void (*exit)(struct clk *clk);
+};
+
 static void devm_clk_release(struct device *dev, void *res)
 {
-	clk_put(*(struct clk **)res);
+	struct devm_clk_state *state = *(struct devm_clk_state **)res;
+
+	if (state->exit)
+		state->exit(state->clk);
+
+	clk_put(state->clk);
 }
 
-struct clk *devm_clk_get(struct device *dev, const char *id)
+static struct clk *__devm_clk_get(struct device *dev, const char *id,
+				  struct clk *(*get)(struct device *dev, const char *id),
+				  int (*init)(struct clk *clk),
+				  void (*exit)(struct clk *clk))
 {
-	struct clk **ptr, *clk;
+	struct devm_clk_state *state;
+	struct clk *clk;
+	int ret;
 
-	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
+	state = devres_alloc(devm_clk_release, sizeof(*state), GFP_KERNEL);
+	if (!state)
 		return ERR_PTR(-ENOMEM);
 
-	clk = clk_get(dev, id);
-	if (!IS_ERR(clk)) {
-		*ptr = clk;
-		devres_add(dev, ptr);
-	} else {
-		devres_free(ptr);
+	clk = get(dev, id);
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		goto err_clk_get;
 	}
 
+	if (init) {
+		ret = init(clk);
+		if (ret)
+			goto err_clk_init;
+	}
+
+	state->clk = clk;
+	state->exit = exit;
+
+	devres_add(dev, state);
+
 	return clk;
+
+err_clk_init:
+
+	clk_put(clk);
+err_clk_get:
+
+	devres_free(state);
+	return ERR_PTR(ret);
+}
+
+struct clk *devm_clk_get(struct device *dev, const char *id)
+{
+	return __devm_clk_get(dev, id, clk_get, NULL, NULL);
 }
 EXPORT_SYMBOL(devm_clk_get);
 
 struct clk *devm_clk_get_optional(struct device *dev, const char *id)
 {
-	struct clk *clk = devm_clk_get(dev, id);
-
-	if (clk == ERR_PTR(-ENOENT))
-		return NULL;
-
-	return clk;
+	return __devm_clk_get(dev, id, clk_get_optional, NULL, NULL);
 }
 EXPORT_SYMBOL(devm_clk_get_optional);