[PATCH RFC 2/3] mmc: core: add new cap for 3.3V only DDR MMCs

From: marex@denx.de (Marek Vasut)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH RFC 2/3] mmc: core: add new cap for 3.3V only DDR MMCs
Date: Sat, 6 Aug 2016 15:14:54 +0200	[thread overview]
Message-ID: <0e38d62a-b3d0-30ca-fca9-bb740ae54d0a@denx.de> (raw)
In-Reply-To: <1470488140-10104-3-git-send-email-stefan.wahren@i2se.com>

On 08/06/2016 02:55 PM, Stefan Wahren wrote:
> This patch based on the work of Fabio Estevam:
> "[PATCH v2] mmc: core: Do not set mmc voltage to 1.8V when
> 'no-1-8-v' is present"
> 
> It adds the support for 3.3V only DDR MMC hosts.

Do such cards even exist ? Do you have a link where I can find some ?

> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
> ---
>  drivers/mmc/core/host.c  |    2 ++
>  drivers/mmc/core/mmc.c   |    6 ++++++
>  include/linux/mmc/host.h |    1 +
>  3 files changed, 9 insertions(+)
> 
> Changes to Fabio's patch:
> - rebase to current linux-next
> - rename DT property to mmc-ddr-3_3v
> - use EXT_CSD_CARD_TYPE_DDR_52 instead of new define
> 
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 98f25ff..4c971de 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -301,6 +301,8 @@ int mmc_of_parse(struct mmc_host *host)
>  	if (of_property_read_bool(np, "wakeup-source") ||
>  	    of_property_read_bool(np, "enable-sdio-wakeup")) /* legacy */
>  		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
> +	if (of_property_read_bool(np, "mmc-ddr-3_3v"))
> +		host->caps2 |= MMC_CAP2_3_3V_ONLY_DDR;
>  	if (of_property_read_bool(np, "mmc-ddr-1_8v"))
>  		host->caps |= MMC_CAP_1_8V_DDR;
>  	if (of_property_read_bool(np, "mmc-ddr-1_2v"))
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index f2d185c..8a933d5 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -210,6 +210,12 @@ static void mmc_select_card_type(struct mmc_card *card)
>  		avail_type |= EXT_CSD_CARD_TYPE_HS_52;
>  	}
>  
> +	if (caps2 & MMC_CAP2_3_3V_ONLY_DDR &&
> +	    card_type & EXT_CSD_CARD_TYPE_DDR_1_8V) {
> +		hs_max_dtr = MMC_HIGH_DDR_MAX_DTR;
> +		avail_type |= EXT_CSD_CARD_TYPE_DDR_52;
> +	}
> +
>  	if (caps & MMC_CAP_1_8V_DDR &&
>  	    card_type & EXT_CSD_CARD_TYPE_DDR_1_8V) {
>  		hs_max_dtr = MMC_HIGH_DDR_MAX_DTR;
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index aa4bfbf..db0775d 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -311,6 +311,7 @@ struct mmc_host {
>  #define MMC_CAP2_HS400_ES	(1 << 20)	/* Host supports enhanced strobe */
>  #define MMC_CAP2_NO_SD		(1 << 21)	/* Do not send SD commands during initialization */
>  #define MMC_CAP2_NO_MMC		(1 << 22)	/* Do not send (e)MMC commands during initialization */
> +#define MMC_CAP2_3_3V_ONLY_DDR	(1 << 23)	/* Only supports 3.3V DDR */
>  
>  	mmc_pm_flag_t		pm_caps;	/* supported pm features */
>  
> 

-- 
Best regards,
Marek Vasut