clk: sunxi-ng: sun50i: a64: Add 2x fixed post-divider to MMC module clocks

On the A64, the MMC module clocks are fixed in the new timing mode,
i.e. they do not have a bit to select the mode. These clocks have
a 2x divider somewhere between the clock and the MMC module.

To be consistent with other SoCs supporting the new timing mode,
we model the 2x divider as a fixed post-divider on the MMC module
clocks.

This patch adds the post-dividers to the MMC clocks.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drivers/clk/sunxi-ng/ccu-sun50i-a64.c

@@ -400,27 +400,44 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(nand_clk, "nand", mod0_default_parents, 0x080,
 				  BIT(31),	/* gate */
 				  0);
 
+/*
+ * MMC clocks are the new timing mode (see A83T & H3) variety, but without
+ * the mode switch. This means they have a 2x post divider between the clock
+ * and the MMC module. This is not documented in the manual, but is taken
+ * into consideration when setting the mmc module clocks in the BSP kernel.
+ * Without it, MMC performance is degraded.
+ *
+ * We model it here to be consistent with other SoCs supporting this mode.
+ * The alternative would be to add the 2x multiplier when setting the MMC
+ * module clock in the MMC driver, just for the A64.
+ */
 static const char * const mmc_default_parents[] = { "osc24M", "pll-periph0-2x",
 						    "pll-periph1-2x" };
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc0_clk, "mmc0", mmc_default_parents, 0x088,
+static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc0_clk, "mmc0",
+					  mmc_default_parents, 0x088,
 					  0, 4,		/* M */
 					  16, 2,	/* P */
 					  24, 2,	/* mux */
 					  BIT(31),	/* gate */
+					  2,		/* post-div */
 					  0);
 
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
+static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc1_clk, "mmc1",
+					  mmc_default_parents, 0x08c,
 					  0, 4,		/* M */
 					  16, 2,	/* P */
 					  24, 2,	/* mux */
 					  BIT(31),	/* gate */
+					  2,		/* post-div */
 					  0);
 
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
+static SUNXI_CCU_MP_WITH_MUX_GATE_POSTDIV(mmc2_clk, "mmc2",
+					  mmc_default_parents, 0x090,
 					  0, 4,		/* M */
 					  16, 2,	/* P */
 					  24, 2,	/* mux */
 					  BIT(31),	/* gate */
+					  2,		/* post-div */
 					  0);
 
 static const char * const ts_parents[] = { "osc24M", "pll-periph0", };