mmc: mediatek: add bus_clk control

mmc: mediatek: add bus_clk control

[Chaotian Jing]

Chaotian Jing (2):
  mmc: dt-bindings: add "bus-clk" for MT2712
  mmc: mediatek: add bus_clk control

 Documentation/devicetree/bindings/mmc/mtk-sd.txt | 1 +
 drivers/mmc/host/mtk-sd.c                        | 6 ++++++
 2 files changed, 7 insertions(+)

-- 
1.8.1.1.dirty

[PATCH 1/2] mmc: dt-bindings: add "bus-clk" for MT2712

[Chaotian Jing]

On MT2712 MSDC0/3, HCLK/bus-clk need gate/ungate together,
or will hang when access MSDC register.

Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
---
 Documentation/devicetree/bindings/mmc/mtk-sd.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/mmc/mtk-sd.txt b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
index f33467a..182299b 100644
--- a/Documentation/devicetree/bindings/mmc/mtk-sd.txt
+++ b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
@@ -22,6 +22,7 @@ Required properties:
 	"source" - source clock (required)
 	"hclk" - HCLK which used for host (required)
 	"source_cg" - independent source clock gate (required for MT2712)
+	"bus_clk" - bus clk used for internal register access(required for MT2712 MSDC0/3)
 - pinctrl-names: should be "default", "state_uhs"
 - pinctrl-0: should contain default/high speed pin ctrl
 - pinctrl-1: should contain uhs mode pin ctrl
-- 
1.8.1.1.dirty

Re: [PATCH 1/2] mmc: dt-bindings: add "bus-clk" for MT2712

[Sean Wang]

On Fri, 2018-09-28 at 19:40 +0800, Chaotian Jing wrote:
> On MT2712 MSDC0/3, HCLK/bus-clk need gate/ungate together,
> or will hang when access MSDC register.
> 
> Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
> ---
>  Documentation/devicetree/bindings/mmc/mtk-sd.txt | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/mtk-sd.txt b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> index f33467a..182299b 100644
> --- a/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> +++ b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> @@ -22,6 +22,7 @@ Required properties:
>  	"source" - source clock (required)
>  	"hclk" - HCLK which used for host (required)
>  	"source_cg" - independent source clock gate (required for MT2712)
> +	"bus_clk" - bus clk used for internal register access(required for MT2712 MSDC0/3)

use a full name in the description such as changing "clk" to "clock" and

add an extra blank char prior to left parenthesis

>  - pinctrl-names: should be "default", "state_uhs"
>  - pinctrl-0: should contain default/high speed pin ctrl
>  - pinctrl-1: should contain uhs mode pin ctrl

Re: [PATCH 1/2] mmc: dt-bindings: add "bus-clk" for MT2712

[Chaotian Jing]

On Sat, 2018-09-29 at 01:34 +0800, Sean Wang wrote:
> On Fri, 2018-09-28 at 19:40 +0800, Chaotian Jing wrote:
> > On MT2712 MSDC0/3, HCLK/bus-clk need gate/ungate together,
> > or will hang when access MSDC register.
> > 
> > Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
> > ---
> >  Documentation/devicetree/bindings/mmc/mtk-sd.txt | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/mmc/mtk-sd.txt b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> > index f33467a..182299b 100644
> > --- a/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> > +++ b/Documentation/devicetree/bindings/mmc/mtk-sd.txt
> > @@ -22,6 +22,7 @@ Required properties:
> >  	"source" - source clock (required)
> >  	"hclk" - HCLK which used for host (required)
> >  	"source_cg" - independent source clock gate (required for MT2712)
> > +	"bus_clk" - bus clk used for internal register access(required for MT2712 MSDC0/3)
> 
> use a full name in the description such as changing "clk" to "clock" and
> 
> add an extra blank char prior to left parenthesis
> 
OK, fixed at v1 version.

> >  - pinctrl-names: should be "default", "state_uhs"
> >  - pinctrl-0: should contain default/high speed pin ctrl
> >  - pinctrl-1: should contain uhs mode pin ctrl
> 
> 

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

[Chaotian Jing]

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

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

[Sean Wang]

Hi,

On Fri, 2018-09-28 at 19:40 +0800, Chaotian Jing wrote:
> 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;

The implementation would cause all SoCs to treat the bus_clk as the optional.
It seems you should add a flag to see what SoC requires the bus_clk to successfully access the related registers.

>  	/*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))

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

[Chaotian Jing]

On Sat, 2018-09-29 at 01:28 +0800, Sean Wang wrote:
> Hi,
> 
> On Fri, 2018-09-28 at 19:40 +0800, Chaotian Jing wrote:
> > 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;
> 
> The implementation would cause all SoCs to treat the bus_clk as the optional.
> It seems you should add a flag to see what SoC requires the bus_clk to successfully access the related registers.

>  Yes, but is no harm to other SoCs, just like the handle of "source_cg"
> >  	/*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))
> 
>