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authorJon Hunter <jonathanh@nvidia.com>2016-07-12 14:53:36 +0100
committerUlf Hansson <ulf.hansson@linaro.org>2016-07-25 10:35:00 +0200
commitefba142bcd980e08ed5e2b98b23b103697d9aa6c (patch)
tree616acff765b1aaf8e2e3a53ff8f861763e780f0e /drivers/mmc
parent1f64cec2b69544899773d88ae7039760e0a3714b (diff)
downloadlinux-efba142bcd980e08ed5e2b98b23b103697d9aa6c.tar.bz2
mmc: sdhci: Request regulators before reading capabilities
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 UHS high speed modes via the presence of the MMC regulators, request the regulators before reading the capabilities of the host controller. This 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@nvidia.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/sdhci.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 31c14b0ff8e2..cd65d474afa2 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3027,6 +3027,16 @@ 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.
+ */
+ ret = mmc_regulator_get_supply(mmc);
+ if (ret == -EPROBE_DEFER)
+ return ret;
+
sdhci_read_caps(host);
override_timeout_clk = host->timeout_clk;
@@ -3259,11 +3269,6 @@ 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;
-
/* 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);