In order to migrate some (few) old clock drivers to the common
mtk_clk_simple_probe() function, add dummy clock ops to be able
to insert a dummy clock with ID 0 at the beginning of the list.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/clk/mediatek/clk-mtk.c | 15 +++++++++++++++
 drivers/clk/mediatek/clk-mtk.h | 19 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c
index a1ab34305b95..d05364e17e95 100644
--- a/drivers/clk/mediatek/clk-mtk.c
+++ b/drivers/clk/mediatek/clk-mtk.c

@@ -18,6 +18,21 @@
 #include "clk-mtk.h"
 #include "clk-gate.h"

+const struct mtk_gate_regs cg_regs_dummy = { 0, 0, 0 };

+
+static int mtk_clk_dummy_enable(struct clk_hw *hw)
+{
+       return 0;
+}
+
+static void mtk_clk_dummy_disable(struct clk_hw *hw) { }
+
+const struct clk_ops mtk_clk_dummy_ops = {
+       .enable         = mtk_clk_dummy_enable,
+       .disable        = mtk_clk_dummy_disable,
+};
+EXPORT_SYMBOL_GPL(mtk_clk_dummy_ops);
+
 static void mtk_init_clk_data(struct clk_hw_onecell_data *clk_data,
                              unsigned int clk_num)
 {

diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
index 15122504c02d..dd43235285db 100644
--- a/drivers/clk/mediatek/clk-mtk.h
+++ b/drivers/clk/mediatek/clk-mtk.h

@@ -22,6 +22,25 @@

 struct platform_device;

+/*
+ * We need the clock IDs to start from zero but to maintain devicetree
+ * backwards compatibility we can't change bindings to start from zero.
+ * Only a few platforms are affected, so we solve issues given by the
+ * commonized MTK clocks probe function(s) by adding a dummy clock at
+ * the beginning where needed.
+ */
+#define CLK_DUMMY              0
+
+extern const struct clk_ops mtk_clk_dummy_ops;
+extern const struct mtk_gate_regs cg_regs_dummy;
+
+#define GATE_DUMMY(_id, _name) {                               \
+               .id = _id,                                      \
+               .name = _name,                                  \
+               .regs = &cg_regs_dummy,                         \
+               .ops = &mtk_clk_dummy_ops,                      \
+       }
+
 struct mtk_fixed_clk {
        int id;
        const char *name;
--

2.39.0