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Subject[PATCH 3/3] mmc: sunxi-mmc: use pll to increase clock speed
Date
Default clock soucre is 24M,if we want clock over 24M
We should use pll as clock source

Signed-off-by: Michael Wu <michael@allwinnertech.com>
---
drivers/mmc/host/sunxi-mmc.c | 57 +++++++++++++++++++++++++++++++++++-
1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 7b47ec453fb6..0039ee58b303 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -756,6 +756,57 @@ static int sunxi_mmc_clk_set_phase(struct sunxi_mmc_host *host,
return 0;
}

+/**
+ *
+ * sunxi_clk_get_parent() - get parent pll from dts
+ * @host: sunxi_mmc_host struct point
+ * @@clock: the clock frequency that requested
+ *
+ * Default clock source is 24M,if we want clock over 24M,We should use
+ * pll as clock soure
+ *
+ * Return:the 0:ok,other:failed
+ */
+static int sunxi_clk_get_parent(struct sunxi_mmc_host *host, u32 clock)
+{
+ struct clk *sclk = NULL;
+ char *sclk_name = NULL;
+ u32 src_clk = 0;
+ s32 err = 0;
+ struct device *dev = mmc_dev(host->mmc);
+
+ sclk = clk_get(dev, "osc24m");
+ sclk_name = "osc24m";
+
+ if (IS_ERR(sclk)) {
+ dev_err(mmc_dev(host->mmc), "Error to get source clock %s\n",
+ sclk_name);
+ return PTR_ERR(sclk);
+ }
+
+ src_clk = clk_get_rate(sclk);
+ if (clock > src_clk) {
+ clk_put(sclk);
+ sclk = clk_get(dev, "pll_periph");
+ sclk_name = "pll_periph";
+ }
+ if (IS_ERR(sclk)) {
+ dev_err(mmc_dev(host->mmc), "Error to get source clock %s\n",
+ sclk_name);
+ return PTR_ERR(sclk);
+ }
+
+ err = clk_set_parent(host->clk_mmc, sclk);
+ if (err) {
+ dev_err(mmc_dev(host->mmc), "set parent failed\n");
+ clk_put(sclk);
+ return err;
+ }
+ clk_put(sclk);
+ return 0;
+}
+
+
static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
struct mmc_ios *ios)
{
@@ -801,7 +852,11 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
return ret;
}
}
-
+ /**
+ * No check return value,because dts may not have osc24M, and pll_periph,
+ * at that time,use default value from clk system
+ */
+ sunxi_clk_get_parent(host, clock);
rate = clk_round_rate(host->clk_mmc, clock);
if (rate < 0) {
dev_err(mmc_dev(mmc), "error rounding clk to %d: %ld\n",
--
2.29.0
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