[PATCH 2/2] mmc: mediatek: add bus_clk control

Chaotian Jing
2018-09-28T11:40:55Z

when gate MSDC0_HCLK, access register will hang, even the MSDC driver
will never accessing register after HCLK was gated, but for safety, need
gate the bus_clk(which used to access register) too.

Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
---
drivers/mmc/host/mtk-sd.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 0484138..1c1c967 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -387,6 +387,7 @@ struct msdc_host {

struct clk *src_clk; /* msdc source clock */
struct clk *h_clk; /* msdc h_clk */
+ struct clk *bus_clk; /* bus clock which used to access register */
struct clk *src_clk_cg; /* msdc source clock control gate */
u32 mclk; /* mmc subsystem clock frequency */
u32 src_clk_freq; /* source clock frequency */
@@ -660,12 +661,14 @@ 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->bus_clk);
clk_disable_unprepare(host->h_clk);
}

static void msdc_ungate_clock(struct msdc_host *host)
{
clk_prepare_enable(host->h_clk);
+ clk_prepare_enable(host->bus_clk);
clk_prepare_enable(host->src_clk);
clk_prepare_enable(host->src_clk_cg);
while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB))
@@ -1900,6 +1903,9 @@ static int msdc_drv_probe(struct platform_device *pdev)
goto host_free;
}

+ host->bus_clk = devm_clk_get(&pdev->dev, "bus_clk");
+ if (IS_ERR(host->bus_clk))
+ host->bus_clk = NULL;
/*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))
--
1.8.1.1.dirty