[PATCH 09/12] mmc: mediatek: add support of source_cg clock

Chaotian Jing
2017-09-12T09:07:49Z

source clock need an independent cg to control, when doing clk mode
switch, need gate source clock to avoid hw issue(multi-bit sync hw hang)

Signed-off-by: Chaotian Jing <chaotian.jing-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
drivers/mmc/host/mtk-sd.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 5d99e05..522fd0a 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -372,6 +372,7 @@ struct msdc_host {

struct clk *src_clk; /* msdc source clock */
struct clk *h_clk; /* msdc h_clk */
+ struct clk *src_clk_cg; /* msdc source clock control gate */
u32 mclk; /* mmc subsystem clock frequency */
u32 src_clk_freq; /* source clock frequency */
u32 sclk; /* SD/MS bus clock frequency */
@@ -612,6 +613,7 @@ static void msdc_set_timeout(struct msdc_host *host, u32 ns, u32 clks)

static void msdc_gate_clock(struct msdc_host *host)
{
+ clk_disable_unprepare(host->src_clk_cg);
clk_disable_unprepare(host->src_clk);
clk_disable_unprepare(host->h_clk);
}
@@ -620,6 +622,7 @@ static void msdc_ungate_clock(struct msdc_host *host)
{
clk_prepare_enable(host->h_clk);
clk_prepare_enable(host->src_clk);
+ clk_prepare_enable(host->src_clk_cg);
while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB))
cpu_relax();
}
@@ -691,6 +694,15 @@ static void msdc_set_mclk(struct msdc_host *host, unsigned char timing, u32 hz)
sclk = (host->src_clk_freq >> 2) / div;
}
}
+ sdr_clr_bits(host->base + MSDC_CFG, MSDC_CFG_CKPDN);
+ /*
+ * As src_clk/HCLK use the same bit to gate/ungate,
+ * So if want to only gate src_clk, need gate its parent(mux).
+ */
+ if (host->src_clk_cg)
+ clk_disable_unprepare(host->src_clk_cg);
+ else
+ clk_disable_unprepare(clk_get_parent(host->src_clk));
if (host->dev_comp->clk_div_bits == 8)
sdr_set_field(host->base + MSDC_CFG,
MSDC_CFG_CKMOD | MSDC_CFG_CKDIV,
@@ -699,10 +711,14 @@ static void msdc_set_mclk(struct msdc_host *host, unsigned char timing, u32 hz)
sdr_set_field(host->base + MSDC_CFG,
MSDC_CFG_CKMOD_EXTRA | MSDC_CFG_CKDIV_EXTRA,
(mode << 12) | div);
+ if (host->src_clk_cg)
+ clk_prepare_enable(host->src_clk_cg);
+ else
+ clk_prepare_enable(clk_get_parent(host->src_clk));

- sdr_set_bits(host->base + MSDC_CFG, MSDC_CFG_CKPDN);
while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB))
cpu_relax();
+ sdr_set_bits(host->base + MSDC_CFG, MSDC_CFG_CKPDN);
host->sclk = sclk;
host->mclk = hz;
host->timing = timing;
@@ -1832,6 +1848,11 @@ static int msdc_drv_probe(struct platform_device *pdev)
goto host_free;
}

+ /*source clock control gate is optional clock*/
+ host->src_clk_cg = devm_clk_get(&pdev->dev, "source_cg");
+ if (IS_ERR(host->src_clk_cg))
+ host->src_clk_cg = NULL;
+
host->irq = platform_get_irq(pdev, 0);
if (host->irq < 0) {
ret = -EINVAL;
--
1.8.1.1.dirty

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