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Subject[PATCH 2/2] clk: sunxi-ng: sun50i: a64: Add 2x fixed post-divider to MMC module clocks
Date
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>
---
drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 57 +++++++++++++++++++++++------------
1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index 2bb4cabf802f..ee9c12cf3f08 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -400,28 +400,45 @@ 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,
- 0, 4, /* M */
- 16, 2, /* P */
- 24, 2, /* mux */
- BIT(31), /* gate */
- 0);
-
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc1_clk, "mmc1", mmc_default_parents, 0x08c,
- 0, 4, /* M */
- 16, 2, /* P */
- 24, 2, /* mux */
- BIT(31), /* gate */
- 0);
-
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mmc_default_parents, 0x090,
- 0, 4, /* M */
- 16, 2, /* P */
- 24, 2, /* mux */
- BIT(31), /* gate */
- 0);
+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_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_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", };
static SUNXI_CCU_MP_WITH_MUX_GATE(ts_clk, "ts", ts_parents, 0x098,
--
2.15.0
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