linux-kernel - Re: [PATCH 7/9] mmc: mmci: add volt

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Message-ID: <CAPDyKFqt6SuQh8V1_2-2HzBixR2HTKM+1FKgYuNA1zytc22W7g@mail.gmail.com>
Date:   Fri, 24 Jan 2020 14:12:36 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Ludovic Barre <ludovic.barre@...com>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH 7/9] mmc: mmci: add volt_switch callbacks

On Fri, 10 Jan 2020 at 14:49, Ludovic Barre <ludovic.barre@...com> wrote:
>
> This patch adds 2 voltage switch callbacks in mmci_host_ops:
> -prep_volt_switch allows to prepare voltage switch before to
>  sent the SD_SWITCH_VOLTAGE command (cmd11).
> -volt_switch callback allows to define specific action after
>  regulator set voltage.

I am fine with adding these callbacks, however I strongly suggest to
have a reference to "signal voltage" in the name of the callbacks. As
to avoid confusion for what there are used for.

Perhaps ->post_sig_volt_switch() and ->pre_sig_volt_switch() can work?

>
> Signed-off-by: Ludovic Barre <ludovic.barre@...com>
> ---
>  drivers/mmc/host/mmci.c | 8 ++++++++
>  drivers/mmc/host/mmci.h | 2 ++
>  2 files changed, 10 insertions(+)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 00b473f57047..d76a59c06cb0 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -22,6 +22,7 @@
>  #include <linux/mmc/pm.h>
>  #include <linux/mmc/host.h>
>  #include <linux/mmc/card.h>
> +#include <linux/mmc/sd.h>
>  #include <linux/mmc/slot-gpio.h>
>  #include <linux/amba/bus.h>
>  #include <linux/clk.h>
> @@ -1207,6 +1208,9 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c)
>                 writel_relaxed(clks, host->base + MMCIDATATIMER);
>         }
>
> +       if (host->ops->prep_volt_switch && cmd->opcode == SD_SWITCH_VOLTAGE)
> +               host->ops->prep_volt_switch(host);
> +
>         if (/*interrupt*/0)
>                 c |= MCI_CPSM_INTERRUPT;
>
> @@ -1820,6 +1824,7 @@ static int mmci_get_cd(struct mmc_host *mmc)
>
>  static int mmci_sig_volt_switch(struct mmc_host *mmc, struct mmc_ios *ios)
>  {
> +       struct mmci_host *host = mmc_priv(mmc);
>         int ret = 0;
>
>         if (!IS_ERR(mmc->supply.vqmmc)) {
> @@ -1839,6 +1844,9 @@ static int mmci_sig_volt_switch(struct mmc_host *mmc, struct mmc_ios *ios)
>                         break;
>                 }
>
> +               if (!ret && host->ops && host->ops->volt_switch)
> +                       ret = host->ops->volt_switch(host, ios);
> +
>                 if (ret)
>                         dev_warn(mmc_dev(mmc), "Voltage switch failed\n");
>         }
> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
> index ddcdfb827996..c04a144259a2 100644
> --- a/drivers/mmc/host/mmci.h
> +++ b/drivers/mmc/host/mmci.h
> @@ -377,6 +377,8 @@ struct mmci_host_ops {
>         void (*set_clkreg)(struct mmci_host *host, unsigned int desired);
>         void (*set_pwrreg)(struct mmci_host *host, unsigned int pwr);
>         bool (*busy_complete)(struct mmci_host *host, u32 status, u32 err_msk);
> +       void (*prep_volt_switch)(struct mmci_host *host);
> +       int (*volt_switch)(struct mmci_host *host, struct mmc_ios *ios);
>  };
>
>  struct mmci_host {
> --
> 2.17.1
>

Kind regards
Uffe