[v2] mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch

The sdhci_start_signal_voltage_switch function sets
V1P8_SIGNAL_ENA by default after switching to 1v8 signaling.
V1P8_SIGNAL_ENA determines whether to launch cmd/data on neg
edge or pos edge of clock.

Due to some eMMC and SD failures seen across am62x platform,
do not set V1P8_SIGNAL_ENA by default, only enable the bit
for devices that require this bit in order to switch to 1v8
voltage for uhs modes.

Signed-off-by: Judith Mendez <jm@ti.com>
---
Changes since v1:
- Invert quirk logic
- Simplify sdhci_am654_start_signal_voltage_switch() and call
  sdhci_start_signal_voltage_switch() when the quirk does not apply
- Simply logic when detecting when quirk should be applied
---
 drivers/mmc/host/sdhci_am654.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)


base-commit: cf6444ba528f043398b112ac36e041a4d8685cb1

On Fri, 13 Sept 2024 at 20:54, Judith Mendez <jm@ti.com> wrote:
>
> The sdhci_start_signal_voltage_switch function sets
> V1P8_SIGNAL_ENA by default after switching to 1v8 signaling.
> V1P8_SIGNAL_ENA determines whether to launch cmd/data on neg
> edge or pos edge of clock.
>
> Due to some eMMC and SD failures seen across am62x platform,
> do not set V1P8_SIGNAL_ENA by default, only enable the bit
> for devices that require this bit in order to switch to 1v8
> voltage for uhs modes.
>
> Signed-off-by: Judith Mendez <jm@ti.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
> Changes since v1:
> - Invert quirk logic
> - Simplify sdhci_am654_start_signal_voltage_switch() and call
>   sdhci_start_signal_voltage_switch() when the quirk does not apply
> - Simply logic when detecting when quirk should be applied
> ---
>  drivers/mmc/host/sdhci_am654.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
> index 0aa3c40ea6ed8..9ff07aadb2d91 100644
> --- a/drivers/mmc/host/sdhci_am654.c
> +++ b/drivers/mmc/host/sdhci_am654.c
> @@ -155,6 +155,7 @@ struct sdhci_am654_data {
>         u32 tuning_loop;
>
>  #define SDHCI_AM654_QUIRK_FORCE_CDTEST BIT(0)
> +#define SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA BIT(1)
>  };
>
>  struct window {
> @@ -356,6 +357,29 @@ static void sdhci_j721e_4bit_set_clock(struct sdhci_host *host,
>         sdhci_set_clock(host, clock);
>  }
>
> +static int sdhci_am654_start_signal_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
> +{
> +       struct sdhci_host *host = mmc_priv(mmc);
> +       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +       struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
> +       int ret;
> +
> +       if ((sdhci_am654->quirks & SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA) &&
> +           ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
> +               if (!IS_ERR(mmc->supply.vqmmc)) {
> +                       ret = mmc_regulator_set_vqmmc(mmc, ios);
> +                       if (ret < 0) {
> +                               pr_err("%s: Switching to 1.8V signalling voltage failed,\n",
> +                                      mmc_hostname(mmc));
> +                               return -EIO;
> +                       }
> +               }
> +               return 0;
> +       }
> +
> +       return sdhci_start_signal_voltage_switch(mmc, ios);
> +}
> +
>  static u8 sdhci_am654_write_power_on(struct sdhci_host *host, u8 val, int reg)
>  {
>         writeb(val, host->ioaddr + reg);
> @@ -844,6 +868,11 @@ static int sdhci_am654_get_of_property(struct platform_device *pdev,
>         if (device_property_read_bool(dev, "ti,fails-without-test-cd"))
>                 sdhci_am654->quirks |= SDHCI_AM654_QUIRK_FORCE_CDTEST;
>
> +       /* Suppress v1p8 ena for eMMC and SD with vqmmc supply */
> +       if (!!of_parse_phandle(dev->of_node, "vmmc-supply", 0) ==
> +           !!of_parse_phandle(dev->of_node, "vqmmc-supply", 0))
> +               sdhci_am654->quirks |= SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA;
> +
>         sdhci_get_of_property(pdev);
>
>         return 0;
> @@ -940,6 +969,7 @@ static int sdhci_am654_probe(struct platform_device *pdev)
>                 goto err_pltfm_free;
>         }
>
> +       host->mmc_host_ops.start_signal_voltage_switch = sdhci_am654_start_signal_voltage_switch;
>         host->mmc_host_ops.execute_tuning = sdhci_am654_execute_tuning;
>
>         pm_runtime_get_noresume(dev);
>
> base-commit: cf6444ba528f043398b112ac36e041a4d8685cb1
> --
> 2.46.0
>