2018-07-05 12:19:18

by Stefan Agner

Subject: [PATCH] mmc: sdhci: do not try to use 3.3V signaling if not supported

For eMMC devices it is valid to only support 1.8V signaling. When
vqmmc is set to a fixed 1.8V regulator the stack tries to set 3.3V
initially and prints the following warning:
mmc1: Switching to 3.3V signalling voltage failed

Clear the MMC_SIGNAL_VOLTAGE_330 flag in case 3.3V is signaling is
not available. This prevents the stack from even trying to use
3.3V signaling and avoids the above warning.

Signed-off-by: Stefan Agner <[email protected]>
---
drivers/mmc/host/sdhci.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1c828e0e9905..a7b5602ef6f7 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3734,14 +3734,21 @@ int sdhci_setup_host(struct sdhci_host *host)
mmc_gpio_get_cd(host->mmc) < 0)
mmc->caps |= MMC_CAP_NEEDS_POLL;

- /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
if (!IS_ERR(mmc->supply.vqmmc)) {
ret = regulator_enable(mmc->supply.vqmmc);
+
+ /* If vqmmc provides no 1.8V signalling, then there's no UHS */
if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
1950000))
host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
SDHCI_SUPPORT_SDR50 |
SDHCI_SUPPORT_DDR50);
+
+ /* In eMMC case vqmmc might be a fixed 1.8V regulator */
+ if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 2700000,
+ 3600000))
+ host->flags &= ~SDHCI_SIGNALING_330;
+
if (ret) {
pr_warn("%s: Failed to enable vqmmc regulator: %d\n",
mmc_hostname(mmc), ret);
--
2.18.0

2018-07-05 13:12:11

by Ulf Hansson

Subject: Re: [PATCH] mmc: sdhci: do not try to use 3.3V signaling if not supported

On 5 July 2018 at 14:18, Stefan Agner <[email protected]> wrote:
> For eMMC devices it is valid to only support 1.8V signaling. When
> vqmmc is set to a fixed 1.8V regulator the stack tries to set 3.3V
> initially and prints the following warning:
> mmc1: Switching to 3.3V signalling voltage failed
>
> Clear the MMC_SIGNAL_VOLTAGE_330 flag in case 3.3V is signaling is
> not available. This prevents the stack from even trying to use
> 3.3V signaling and avoids the above warning.
>
> Signed-off-by: Stefan Agner <[email protected]>

Thanks, applied for next!

Kind regards
Uffe

> ---
> drivers/mmc/host/sdhci.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 1c828e0e9905..a7b5602ef6f7 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3734,14 +3734,21 @@ int sdhci_setup_host(struct sdhci_host *host)
> mmc_gpio_get_cd(host->mmc) < 0)
> mmc->caps |= MMC_CAP_NEEDS_POLL;
>
> - /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> if (!IS_ERR(mmc->supply.vqmmc)) {
> ret = regulator_enable(mmc->supply.vqmmc);
> +
> + /* If vqmmc provides no 1.8V signalling, then there's no UHS */
> if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
> 1950000))
> host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
> SDHCI_SUPPORT_SDR50 |
> SDHCI_SUPPORT_DDR50);
> +
> + /* In eMMC case vqmmc might be a fixed 1.8V regulator */
> + if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 2700000,
> + 3600000))
> + host->flags &= ~SDHCI_SIGNALING_330;
> +
> if (ret) {
> pr_warn("%s: Failed to enable vqmmc regulator: %d\n",
> mmc_hostname(mmc), ret);
> --
> 2.18.0
>