Re: [PATCH v4 09/11] mmc: sdhci-omap: Add ti,needs-special-reset property

From: Adrian Hunter
Date: Wed Jan 15 2020 - 07:15:06 EST


On 6/01/20 1:01 pm, Faiz Abbas wrote:
> Some omap controllers need software to monitor a 0->1->0 for software
> reset. Add a ti,needs-special-reset property to indicate this and use
> the special_reset member to indicate when a controller needs this.
>
> Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
> drivers/mmc/host/sdhci-omap.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
> index 1f05c8e98d62..34df30edd450 100644
> --- a/drivers/mmc/host/sdhci-omap.c
> +++ b/drivers/mmc/host/sdhci-omap.c
> @@ -107,6 +107,7 @@ struct sdhci_omap_host {
> struct pinctrl *pinctrl;
> struct pinctrl_state **pinctrl_state;
> bool is_tuning;
> + bool special_reset;
> };
>
> static void sdhci_omap_start_clock(struct sdhci_omap_host *omap_host);
> @@ -779,15 +780,35 @@ static void sdhci_omap_set_uhs_signaling(struct sdhci_host *host,
> sdhci_omap_start_clock(omap_host);
> }
>
> +#define MMC_TIMEOUT_US 20000 /* 20000 micro Sec */
> static void sdhci_omap_reset(struct sdhci_host *host, u8 mask)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
> + unsigned long limit = MMC_TIMEOUT_US;
> + unsigned long i = 0;
>
> /* Don't reset data lines during tuning operation */
> if (omap_host->is_tuning)
> mask &= ~SDHCI_RESET_DATA;
>
> + if (omap_host->special_reset) {
> + sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
> + while ((!(sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask)) &&
> + (i++ < limit))
> + udelay(1);
> + i = 0;
> + while ((sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) &&
> + (i++ < limit))
> + udelay(1);
> +
> + if (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask)
> + dev_err(mmc_dev(host->mmc),
> + "Timeout waiting on controller reset in %s\n",
> + __func__);
> + return;
> + }
> +
> sdhci_reset(host, mask);
> }
>
> @@ -1107,6 +1128,9 @@ static int sdhci_omap_probe(struct platform_device *pdev)
> if (!mmc_can_gpio_ro(mmc))
> mmc->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
>
> + if (of_find_property(dev->of_node, "ti,needs-special-reset", NULL))
> + omap_host->special_reset = true;
> +
> pltfm_host->clk = devm_clk_get(dev, "fck");
> if (IS_ERR(pltfm_host->clk)) {
> ret = PTR_ERR(pltfm_host->clk);
>