[PATCH v2 1/4] clk: mediatek: mt8173: Fix enabling of critical clocks

[James Liao]

From: Sascha Hauer <s.hauer at pengutronix.de>

On the MT8173 the clocks are provided by different units. To enable
the critical clocks we must be sure that all parent clocks are already
registered, otherwise the parents of the critical clocks end up being
unused and get disabled later. To find a place where all parents are
registered we try each time after we've registered some clocks if
all known providers are present now and only then we enable the critical
clocks

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Signed-off-by: James Liao <jamesjj.liao at mediatek.com>
---
 drivers/clk/mediatek/clk-mt8173.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/mediatek/clk-mt8173.c b/drivers/clk/mediatek/clk-mt8173.c
index 4b9e04c..c483336 100644
--- a/drivers/clk/mediatek/clk-mt8173.c
+++ b/drivers/clk/mediatek/clk-mt8173.c
@@ -700,6 +700,22 @@ static const struct mtk_composite peri_clks[] __initconst = {
 	MUX(CLK_PERI_UART3_SEL, "uart3_ck_sel", uart_ck_sel_parents, 0x40c, 3, 1),
 };
 
+static struct clk_onecell_data *mt8173_top_clk_data;
+static struct clk_onecell_data *mt8173_pll_clk_data;
+
+static void mtk_clk_enable_critical(void)
+{
+	if (!mt8173_top_clk_data || !mt8173_pll_clk_data)
+		return;
+
+	clk_prepare_enable(mt8173_pll_clk_data->clks[CLK_APMIXED_ARMCA15PLL]);
+	clk_prepare_enable(mt8173_pll_clk_data->clks[CLK_APMIXED_ARMCA7PLL]);
+	clk_prepare_enable(mt8173_top_clk_data->clks[CLK_TOP_MEM_SEL]);
+	clk_prepare_enable(mt8173_top_clk_data->clks[CLK_TOP_DDRPHYCFG_SEL]);
+	clk_prepare_enable(mt8173_top_clk_data->clks[CLK_TOP_CCI400_SEL]);
+	clk_prepare_enable(mt8173_top_clk_data->clks[CLK_TOP_RTC_SEL]);
+}
+
 static void __init mtk_topckgen_init(struct device_node *node)
 {
 	struct clk_onecell_data *clk_data;
@@ -712,19 +728,19 @@ static void __init mtk_topckgen_init(struct device_node *node)
 		return;
 	}
 
-	clk_data = mtk_alloc_clk_data(CLK_TOP_NR_CLK);
+	mt8173_top_clk_data = clk_data = mtk_alloc_clk_data(CLK_TOP_NR_CLK);
 
 	mtk_clk_register_factors(root_clk_alias, ARRAY_SIZE(root_clk_alias), clk_data);
 	mtk_clk_register_factors(top_divs, ARRAY_SIZE(top_divs), clk_data);
 	mtk_clk_register_composites(top_muxes, ARRAY_SIZE(top_muxes), base,
 			&mt8173_clk_lock, clk_data);
 
-	clk_prepare_enable(clk_data->clks[CLK_TOP_CCI400_SEL]);
-
 	r = of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
 	if (r)
 		pr_err("%s(): could not register clock provider: %d\n",
 			__func__, r);
+
+	mtk_clk_enable_critical();
 }
 CLK_OF_DECLARE(mtk_topckgen, "mediatek,mt8173-topckgen", mtk_topckgen_init);
 
@@ -818,13 +834,13 @@ static void __init mtk_apmixedsys_init(struct device_node *node)
 {
 	struct clk_onecell_data *clk_data;
 
-	clk_data = mtk_alloc_clk_data(CLK_APMIXED_NR_CLK);
+	mt8173_pll_clk_data = clk_data = mtk_alloc_clk_data(CLK_APMIXED_NR_CLK);
 	if (!clk_data)
 		return;
 
 	mtk_clk_register_plls(node, plls, ARRAY_SIZE(plls), clk_data);
 
-	clk_prepare_enable(clk_data->clks[CLK_APMIXED_ARMCA15PLL]);
+	mtk_clk_enable_critical();
 }
 CLK_OF_DECLARE(mtk_apmixedsys, "mediatek,mt8173-apmixedsys",
 		mtk_apmixedsys_init);
-- 
1.8.1.1.dirty