linux-kernel - Re: [PATCHv2 09/21] mmc: sdhci-of-dwcmshc: add reset call back for rockchip Socs

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Date:   Fri, 6 May 2022 10:52:42 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>
Cc:     Heiko Stuebner <heiko@...ech.de>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...ts.collabora.co.uk,
        Yifeng Zhao <yifeng.zhao@...k-chips.com>, kernel@...labora.com
Subject: Re: [PATCHv2 09/21] mmc: sdhci-of-dwcmshc: add reset call back for
 rockchip Socs

On Wed, 4 May 2022 at 23:33, Sebastian Reichel
<sebastian.reichel@...labora.com> wrote:
>
> From: Yifeng Zhao <yifeng.zhao@...k-chips.com>
>
> The reset function build in the SDHCI will not reset the logic
> circuit related to the tuning function, which may cause data
> reading errors. Resetting the complete SDHCI controller through
> the reset controller fixes the issue.
>
> Signed-off-by: Yifeng Zhao <yifeng.zhao@...k-chips.com>
> [rebase, use optional variant of reset getter]
> Acked-by: Adrian Hunter <adrian.hunter@...el.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>

I think this needs a corresponding update of the DT docs. Otherwise
this looks good to me.

Kind regards
Uffe

> ---
>  drivers/mmc/host/sdhci-of-dwcmshc.c | 26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
> index bac874ab0b33..3a1b5ba36405 100644
> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
> @@ -15,6 +15,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> +#include <linux/reset.h>
>  #include <linux/sizes.h>
>
>  #include "sdhci-pltfm.h"
> @@ -63,6 +64,7 @@
>  struct rk3568_priv {
>         /* Rockchip specified optional clocks */
>         struct clk_bulk_data rockchip_clks[RK3568_MAX_CLKS];
> +       struct reset_control *reset;
>         u8 txclk_tapnum;
>  };
>
> @@ -255,6 +257,21 @@ static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock
>         sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_STRBIN);
>  }
>
> +static void rk35xx_sdhci_reset(struct sdhci_host *host, u8 mask)
> +{
> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +       struct dwcmshc_priv *dwc_priv = sdhci_pltfm_priv(pltfm_host);
> +       struct rk35xx_priv *priv = dwc_priv->priv;
> +
> +       if (mask & SDHCI_RESET_ALL && priv->reset) {
> +               reset_control_assert(priv->reset);
> +               udelay(1);
> +               reset_control_deassert(priv->reset);
> +       }
> +
> +       sdhci_reset(host, mask);
> +}
> +
>  static const struct sdhci_ops sdhci_dwcmshc_ops = {
>         .set_clock              = sdhci_set_clock,
>         .set_bus_width          = sdhci_set_bus_width,
> @@ -269,7 +286,7 @@ static const struct sdhci_ops sdhci_dwcmshc_rk3568_ops = {
>         .set_bus_width          = sdhci_set_bus_width,
>         .set_uhs_signaling      = dwcmshc_set_uhs_signaling,
>         .get_max_clock          = sdhci_pltfm_clk_get_max_clock,
> -       .reset                  = sdhci_reset,
> +       .reset                  = rk35xx_sdhci_reset,
>         .adma_write_desc        = dwcmshc_adma_write_desc,
>  };
>
> @@ -292,6 +309,13 @@ static int dwcmshc_rk3568_init(struct sdhci_host *host, struct dwcmshc_priv *dwc
>         int err;
>         struct rk3568_priv *priv = dwc_priv->priv;
>
> +       priv->reset = devm_reset_control_array_get_optional_exclusive(mmc_dev(host->mmc));
> +       if (IS_ERR(priv->reset)) {
> +               err = PTR_ERR(priv->reset);
> +               dev_err(mmc_dev(host->mmc), "failed to get reset control %d\n", err);
> +               return err;
> +       }
> +
>         priv->rockchip_clks[0].id = "axi";
>         priv->rockchip_clks[1].id = "block";
>         priv->rockchip_clks[2].id = "timer";
> --
> 2.35.1
>