The MMC2 clock supports a new timing mode. When the new mode is active,
the output clock rate is halved.
This patch sets the feature flag for the new timing mode, and adds
a pre-divider based on the mode bit.
Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
---
drivers/clk/sunxi-ng/ccu-sun8i-a83t.c | 38 +++++++++++++++++++++++++++--------
1 file changed, 30 insertions(+), 8 deletions(-)
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
index 947f9f6e05d2..ee6688e9b361 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
@@ -418,14 +418,36 @@ static SUNXI_CCU_PHASE(mmc1_sample_clk, "mmc1-sample", "mmc1",
static SUNXI_CCU_PHASE(mmc1_output_clk, "mmc1-output", "mmc1",
0x08c, 8, 3, 0);
-/* TODO Support MMC2 clock's new timing mode. */
-static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mod0_default_parents,
- 0x090,
- 0, 4, /* M */
- 16, 2, /* P */
- 24, 2, /* mux */
- BIT(31), /* gate */
- 0);
+/*
+ * MMC2 supports both old and new timing modes. When the new timing
+ * mode is active, the output clock rate is halved by two. Here we
+ * treat it as a variable pre-divider. Note that the pre-divider is
+ * _not_ included in the possible factors during a set clock rate
+ * operation. It is only read out.
+ */
+static const struct ccu_mux_var_prediv mmc2_new_timing_predivs[] = {
+ { .index = 0, .shift = 30, .width = 1 },
+ { .index = 1, .shift = 30, .width = 1 },
+};
+static struct ccu_mp mmc2_clk = {
+ .enable = BIT(31),
+ .m = _SUNXI_CCU_DIV(0, 4),
+ .p = _SUNXI_CCU_DIV(16, 2),
+ .mux = {
+ .shift = 24,
+ .width = 2,
+ .var_predivs = mmc2_new_timing_predivs,
+ .n_var_predivs = ARRAY_SIZE(mmc2_new_timing_predivs),
+ },
+ .common = {
+ .reg = 0x090,
+ .features = CCU_FEATURE_MMC_TIMING_SWITCH,
+ .hw.init = CLK_HW_INIT_PARENTS("mmc2",
+ mod0_default_parents,
+ &ccu_mp_ops,
+ CLK_GET_RATE_NOCACHE),
+ },
+};
static SUNXI_CCU_PHASE(mmc2_sample_clk, "mmc2-sample", "mmc2",
0x090, 20, 3, 0);
--
2.13.2
--
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