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

From: Adrian Hunter <adrian.hunter@intel.com>
To: Iker Pedrosa <ikerpedrosam@gmail.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>, Yixun Lan <dlan@kernel.org>
Cc: Michael Opdenacker <michael.opdenacker@rootcommit.com>,
	"Javier Martinez Canillas" <javierm@redhat.com>,
	<linux-mmc@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-riscv@lists.infradead.org>, <spacemit@lists.linux.dev>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/7] mmc: sdhci-of-k1: enable essential clock infrastructure for SD operation
Date: Fri, 13 Mar 2026 15:04:34 +0200	[thread overview]
Message-ID: <a416dc43-58fd-4462-9ec5-b3dadbbacf8b@intel.com> (raw)
In-Reply-To: <20260309-orangepi-sd-card-uhs-v2-1-5bb2b574df5d@gmail.com>

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)
>