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[PATCH v2 1/7] mmc: sdhci-of-k1: enable essential clock infrastructure for SD operation

Iker Pedrosa posted 7 patches 1 month ago
There is a newer version of this series
[PATCH v2 1/7] mmc: sdhci-of-k1: enable essential clock infrastructure for SD operation
Posted by Iker Pedrosa 1 month ago 
Ensure SD card pins receive clock signals by enabling pad clock
generation and overriding automatic clock gating. Required for all SD
operation modes.

Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
---
 drivers/mmc/host/sdhci-of-k1.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
index 0cc97e23a2f9c7b2f9376318a8a7ebb860571504..585c7eca6ebf253aac466dd37cef029deb63f692 100644
--- a/drivers/mmc/host/sdhci-of-k1.c
+++ b/drivers/mmc/host/sdhci-of-k1.c
@@ -20,6 +20,13 @@
 #include "sdhci.h"
 #include "sdhci-pltfm.h"
 
+#define SPACEMIT_SDHC_OP_EXT_REG	0x108
+#define  SDHC_OVRRD_CLK_OEN		BIT(11)
+#define  SDHC_FORCE_CLK_ON		BIT(12)
+
+#define SPACEMIT_SDHC_LEGACY_CTRL_REG	0x10C
+#define  SDHC_GEN_PAD_CLK_ON		BIT(6)
+
 #define SPACEMIT_SDHC_MMC_CTRL_REG	0x114
 #define  SDHC_MISC_INT_EN		BIT(1)
 #define  SDHC_MISC_INT			BIT(2)
@@ -100,6 +107,12 @@ static void spacemit_sdhci_reset(struct sdhci_host *host, u8 mask)
 
 	if (!(host->mmc->caps2 & MMC_CAP2_NO_MMC))
 		spacemit_sdhci_setbits(host, SDHC_MMC_CARD_MODE, SPACEMIT_SDHC_MMC_CTRL_REG);
+
+	spacemit_sdhci_setbits(host, SDHC_GEN_PAD_CLK_ON, SPACEMIT_SDHC_LEGACY_CTRL_REG);
+
+	if (host->mmc->caps2 & MMC_CAP2_NO_MMC)
+		spacemit_sdhci_setbits(host, SDHC_OVRRD_CLK_OEN | SDHC_FORCE_CLK_ON,
+				       SPACEMIT_SDHC_OP_EXT_REG);
 }
 
 static void spacemit_sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)

-- 
2.53.0
Re: [PATCH v2 1/7] mmc: sdhci-of-k1: enable essential clock infrastructure for SD operation
Posted by Adrian Hunter 3 weeks, 5 days ago 
On 09/03/2026 13:40, Iker Pedrosa wrote:
> Ensure SD card pins receive clock signals by enabling pad clock
> generation and overriding automatic clock gating. Required for all SD
> operation modes.

Need to say why update to "SPACEMIT_SDHC_LEGACY_CTRL_REG" is Ok for
non-SD

> 
> Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> ---
>  drivers/mmc/host/sdhci-of-k1.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> index 0cc97e23a2f9c7b2f9376318a8a7ebb860571504..585c7eca6ebf253aac466dd37cef029deb63f692 100644
> --- a/drivers/mmc/host/sdhci-of-k1.c
> +++ b/drivers/mmc/host/sdhci-of-k1.c
> @@ -20,6 +20,13 @@
>  #include "sdhci.h"
>  #include "sdhci-pltfm.h"
>  
> +#define SPACEMIT_SDHC_OP_EXT_REG	0x108
> +#define  SDHC_OVRRD_CLK_OEN		BIT(11)
> +#define  SDHC_FORCE_CLK_ON		BIT(12)
> +
> +#define SPACEMIT_SDHC_LEGACY_CTRL_REG	0x10C
> +#define  SDHC_GEN_PAD_CLK_ON		BIT(6)
> +
>  #define SPACEMIT_SDHC_MMC_CTRL_REG	0x114
>  #define  SDHC_MISC_INT_EN		BIT(1)
>  #define  SDHC_MISC_INT			BIT(2)
> @@ -100,6 +107,12 @@ static void spacemit_sdhci_reset(struct sdhci_host *host, u8 mask)
>  
>  	if (!(host->mmc->caps2 & MMC_CAP2_NO_MMC))
>  		spacemit_sdhci_setbits(host, SDHC_MMC_CARD_MODE, SPACEMIT_SDHC_MMC_CTRL_REG);
> +
> +	spacemit_sdhci_setbits(host, SDHC_GEN_PAD_CLK_ON, SPACEMIT_SDHC_LEGACY_CTRL_REG);
> +
> +	if (host->mmc->caps2 & MMC_CAP2_NO_MMC)
> +		spacemit_sdhci_setbits(host, SDHC_OVRRD_CLK_OEN | SDHC_FORCE_CLK_ON,
> +				       SPACEMIT_SDHC_OP_EXT_REG);
>  }
>  
>  static void spacemit_sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
>
Re: [PATCH v2 1/7] mmc: sdhci-of-k1: enable essential clock infrastructure for SD operation
Posted by Iker Pedrosa 3 weeks, 3 days ago 
El vie, 13 mar 2026 a las 14:04, Adrian Hunter
(<adrian.hunter@intel.com>) escribió:
>
> On 09/03/2026 13:40, Iker Pedrosa wrote:
> > Ensure SD card pins receive clock signals by enabling pad clock
> > generation and overriding automatic clock gating. Required for all SD
> > operation modes.
>
> Need to say why update to "SPACEMIT_SDHC_LEGACY_CTRL_REG" is Ok for
> non-SD

After analyzing the reference driver implementation[1], the
SDHC_LEGACY_CTRL_REG setting is applied to both eMMC and SD
controllers.

The reference driver sets GEN_PAD_CLK_ON for any controller with
MMC_CAP2_NO_SDIO set (SDIO disabled). Since both our eMMC and SD
controllers have no-sdio; in their device tree configurations, both
should receive this setting.

[1] https://github.com/orangepi-xunlong/linux-orangepi/blob/orange-pi-6.6-ky/drivers/mmc/host/sdhci-of-x1.c#L482

>
> >
> > Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
> > ---
> >  drivers/mmc/host/sdhci-of-k1.c | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> > index 0cc97e23a2f9c7b2f9376318a8a7ebb860571504..585c7eca6ebf253aac466dd37cef029deb63f692 100644
> > --- a/drivers/mmc/host/sdhci-of-k1.c
> > +++ b/drivers/mmc/host/sdhci-of-k1.c
> > @@ -20,6 +20,13 @@
> >  #include "sdhci.h"
> >  #include "sdhci-pltfm.h"
> >
> > +#define SPACEMIT_SDHC_OP_EXT_REG     0x108
> > +#define  SDHC_OVRRD_CLK_OEN          BIT(11)
> > +#define  SDHC_FORCE_CLK_ON           BIT(12)
> > +
> > +#define SPACEMIT_SDHC_LEGACY_CTRL_REG        0x10C
> > +#define  SDHC_GEN_PAD_CLK_ON         BIT(6)
> > +
> >  #define SPACEMIT_SDHC_MMC_CTRL_REG   0x114
> >  #define  SDHC_MISC_INT_EN            BIT(1)
> >  #define  SDHC_MISC_INT                       BIT(2)
> > @@ -100,6 +107,12 @@ static void spacemit_sdhci_reset(struct sdhci_host *host, u8 mask)
> >
> >       if (!(host->mmc->caps2 & MMC_CAP2_NO_MMC))
> >               spacemit_sdhci_setbits(host, SDHC_MMC_CARD_MODE, SPACEMIT_SDHC_MMC_CTRL_REG);
> > +
> > +     spacemit_sdhci_setbits(host, SDHC_GEN_PAD_CLK_ON, SPACEMIT_SDHC_LEGACY_CTRL_REG);
> > +
> > +     if (host->mmc->caps2 & MMC_CAP2_NO_MMC)
> > +             spacemit_sdhci_setbits(host, SDHC_OVRRD_CLK_OEN | SDHC_FORCE_CLK_ON,
> > +                                    SPACEMIT_SDHC_OP_EXT_REG);
> >  }
> >
> >  static void spacemit_sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
> >
>
Re: [PATCH v2 1/7] mmc: sdhci-of-k1: enable essential clock infrastructure for SD operation
Posted by Adrian Hunter 3 weeks, 3 days ago 
On 16/03/2026 11:04, Iker Pedrosa wrote:
> El vie, 13 mar 2026 a las 14:04, Adrian Hunter
> (<adrian.hunter@intel.com>) escribió:
>>
>> On 09/03/2026 13:40, Iker Pedrosa wrote:
>>> Ensure SD card pins receive clock signals by enabling pad clock
>>> generation and overriding automatic clock gating. Required for all SD
>>> operation modes.
>>
>> Need to say why update to "SPACEMIT_SDHC_LEGACY_CTRL_REG" is Ok for
>> non-SD
> 
> After analyzing the reference driver implementation[1], the
> SDHC_LEGACY_CTRL_REG setting is applied to both eMMC and SD
> controllers.
> 
> The reference driver sets GEN_PAD_CLK_ON for any controller with
> MMC_CAP2_NO_SDIO set (SDIO disabled). Since both our eMMC and SD
> controllers have no-sdio; in their device tree configurations, both
> should receive this setting.
> 
> [1] https://github.com/orangepi-xunlong/linux-orangepi/blob/orange-pi-6.6-ky/drivers/mmc/host/sdhci-of-x1.c#L482
> 

"I copied it from somewhere else" is not the best explanation,
but better than nothing I guess.  However I meant add the
explanation to the commit message.

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