clk: mediatek: Implement mtk_clk_unregister_factors() API

mtk_clk_register_factors(), as the name suggests, is used to register
a given list of fixed factor clks. However it is lacking a counterpart
unregister API.

Implement said unregister API so that the various clock platform drivers
can utilize it to do proper unregistration, cleanup and removal.

In the header file, the register function's declaration is also
reformatted to fit code style guidelines.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220208124034.414635-17-wenst@chromium.org
Reviewed-by: Chun-Jie Chen <chun-jie.chen@mediatek.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: wens

drivers/clk/mediatek/clk-mtk.c

@@ -126,6 +126,26 @@ void mtk_clk_register_factors(const struct mtk_fixed_factor *clks,
 }
 EXPORT_SYMBOL_GPL(mtk_clk_register_factors);
 
+void mtk_clk_unregister_factors(const struct mtk_fixed_factor *clks, int num,
+				struct clk_onecell_data *clk_data)
+{
+	int i;
+
+	if (!clk_data)
+		return;
+
+	for (i = num; i > 0; i--) {
+		const struct mtk_fixed_factor *ff = &clks[i - 1];
+
+		if (IS_ERR_OR_NULL(clk_data->clks[ff->id]))
+			continue;
+
+		clk_unregister_fixed_factor(clk_data->clks[ff->id]);
+		clk_data->clks[ff->id] = ERR_PTR(-ENOENT);
+	}
+}
+EXPORT_SYMBOL_GPL(mtk_clk_unregister_factors);
+
 struct clk *mtk_clk_register_composite(const struct mtk_composite *mc,
 		void __iomem *base, spinlock_t *lock)
 {

drivers/clk/mediatek/clk-mtk.h

@@ -55,8 +55,10 @@ struct mtk_fixed_factor {
 		.div = _div,				\
 	}
 
-void mtk_clk_register_factors(const struct mtk_fixed_factor *clks,
-		int num, struct clk_onecell_data *clk_data);
+void mtk_clk_register_factors(const struct mtk_fixed_factor *clks, int num,
+			      struct clk_onecell_data *clk_data);
+void mtk_clk_unregister_factors(const struct mtk_fixed_factor *clks, int num,
+				struct clk_onecell_data *clk_data);
 
 struct mtk_composite {
 	int id;