clk: meson: add mpll pre-divider

mpll clocks parent can actually be divided by 1 or 2. So far, this
divider has always been set to 1, so the calculation was correct.
Now that we know it exists, model the tree correctly. If we ever get
a platform where the divider is different, we won't get into trouble

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
index fdeb372..b62d181 100644
--- a/drivers/clk/meson/gxbb.c
+++ b/drivers/clk/meson/gxbb.c
@@ -545,6 +545,20 @@ static struct clk_fixed_factor gxbb_fclk_div7 = {
 	},
 };
 
+static struct clk_regmap gxbb_mpll_prediv = {
+	.data = &(struct clk_regmap_div_data){
+		.offset = HHI_MPLL_CNTL5,
+		.shift = 12,
+		.width = 1,
+	},
+	.hw.init = &(struct clk_init_data){
+		.name = "mpll_prediv",
+		.ops = &clk_regmap_divider_ro_ops,
+		.parent_names = (const char *[]){ "fixed_pll" },
+		.num_parents = 1,
+	},
+};
+
 static struct clk_regmap gxbb_mpll0_div = {
 	.data = &(struct meson_clk_mpll_data){
 		.sdm = {
@@ -572,7 +586,7 @@ static struct clk_regmap gxbb_mpll0_div = {
 	.hw.init = &(struct clk_init_data){
 		.name = "mpll0_div",
 		.ops = &meson_clk_mpll_ops,
-		.parent_names = (const char *[]){ "fixed_pll" },
+		.parent_names = (const char *[]){ "mpll_prediv" },
 		.num_parents = 1,
 	},
 };
@@ -613,7 +627,7 @@ static struct clk_regmap gxbb_mpll1_div = {
 	.hw.init = &(struct clk_init_data){
 		.name = "mpll1_div",
 		.ops = &meson_clk_mpll_ops,
-		.parent_names = (const char *[]){ "fixed_pll" },
+		.parent_names = (const char *[]){ "mpll_prediv" },
 		.num_parents = 1,
 	},
 };
@@ -654,7 +668,7 @@ static struct clk_regmap gxbb_mpll2_div = {
 	.hw.init = &(struct clk_init_data){
 		.name = "mpll2_div",
 		.ops = &meson_clk_mpll_ops,
-		.parent_names = (const char *[]){ "fixed_pll" },
+		.parent_names = (const char *[]){ "mpll_prediv" },
 		.num_parents = 1,
 	},
 };
@@ -1703,6 +1717,7 @@ static struct clk_hw_onecell_data gxbb_hw_onecell_data = {
 		[CLKID_MPLL0_DIV]	    = &gxbb_mpll0_div.hw,
 		[CLKID_MPLL1_DIV]	    = &gxbb_mpll1_div.hw,
 		[CLKID_MPLL2_DIV]	    = &gxbb_mpll2_div.hw,
+		[CLKID_MPLL_PREDIV]	    = &gxbb_mpll_prediv.hw,
 		[NR_CLKS]		    = NULL,
 	},
 	.num = NR_CLKS,
@@ -1853,6 +1868,7 @@ static struct clk_hw_onecell_data gxl_hw_onecell_data = {
 		[CLKID_MPLL0_DIV]	    = &gxbb_mpll0_div.hw,
 		[CLKID_MPLL1_DIV]	    = &gxbb_mpll1_div.hw,
 		[CLKID_MPLL2_DIV]	    = &gxbb_mpll2_div.hw,
+		[CLKID_MPLL_PREDIV]	    = &gxbb_mpll_prediv.hw,
 		[NR_CLKS]		    = NULL,
 	},
 	.num = NR_CLKS,
@@ -2005,6 +2021,7 @@ static struct clk_regmap *const gx_clk_regmaps[] = {
 	&gxbb_cts_amclk_div,
 	&gxbb_fixed_pll,
 	&gxbb_sys_pll,
+	&gxbb_mpll_prediv,
 };
 
 struct clkc_data {