On 20/07/16 16:02, Adrian Hunter wrote:
> On 12/07/16 16:53, Jon Hunter wrote:
>> The capabilities of the SDHCI host controller are read early during the
>> SDHCI host initialisation in sdhci_setup_host() and before any
>> regulators for the host have been requested. This means that if the host
>> supports some high-speed modes (according to its capabilities register),
>> but the board cannot because the appropriate voltage regulator is not
>> available, then the host cannot easily override the capabilities that
>> are supported.
>>
>> To allow a SDHCI host controller to determine if it can support high
>> speed modes via the presense of the MMC regulators, request the
>
> Try not to confuse High Speed mode with UHS modes.
>
> presense -> presence
>
>> regulators before reading the capabilites of the host controller. This
>
> capabilites -> capabilities
>
>> will allow the SDHCI host to use the 'reset' callback to take the
>> appropriate action (set flags, configure registers, etc) before the
>> capabilities register(s) are read.
>>
>> Please note that some SDHCI hosts, such as the Tegra SDHCI host, has
>> the ability to mask bits in the capabilities register to prevent
>> certain capabilities from being advertised.
>>
>> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
>> ---
>>
>> Although this is described as a "V2" this patch has been added since
>> the original patch was posted.
>>
>> If the below is deemed not appropriate, then another solution I was
>> thinking of is to allow the SDHCI host to call 'mmc_regulator_get_supply'
>> before calling sdhci_setup_host() and then in sdhci_setup_host() check
>> if any regulators are already present before calling
>> mmc_regulator_get_supply().
>
> And we can still do that later if we need to.
>
>>
>> drivers/mmc/host/sdhci.c | 16 +++++++++++-----
>> 1 file changed, 11 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 2ee8bfa77116..628c4b3558c0 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -3021,6 +3021,17 @@ int sdhci_setup_host(struct sdhci_host *host)
>>
>> mmc = host->mmc;
>>
>> + /*
>> + * If there are external regulators, get them. Note
>> + * this must be done early before resetting the host
>> + * and reading the capabilities so that the host can
>> + * take the appropriate action if regulators are not
>> + * available.
Also you could spread this comment out to 80 columns.
>> + */
>> + ret = mmc_regulator_get_supply(mmc);
>> + if (ret == -EPROBE_DEFER)
>> + return ret;
>> +
>> sdhci_read_caps(host);
>>
>> override_timeout_clk = host->timeout_clk;
>> @@ -3253,11 +3264,6 @@ int sdhci_setup_host(struct sdhci_host *host)
>> mmc_gpio_get_cd(host->mmc) < 0)
>> mmc->caps |= MMC_CAP_NEEDS_POLL;
>>
>> - /* If there are external regulators, get them */
>> - ret = mmc_regulator_get_supply(mmc);
>> - if (ret == -EPROBE_DEFER)
>> - goto undma;
>
> All goto's before this now need to goto unreg.
>
>> -
>> /* 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);
>>
>
>
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