[PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails
From: Pavan Kunapuli <hidden>
Date: 2012-10-23 08:16:49
Also in:
linux-mmc, linux-tegra, lkml
quoted
Does this work with boards where we don't have any MMC supplies? Or are we just deferring the probe indefinitely there?
The probe will be deferred indefinitely.
quoted
For boards that power MMC unconditionally, are we supposed to add dummy regulators to make them work with this patchset?
Yes. We need to add dummy regulators for boards that power MMC unconditionally. I am not sure if there is any other solution other than using deferred probe that would guarantee regulators availability. -----Original Message----- From: Lucas Stach [mailto:dev at lynxeye.de] Sent: 23 October 2012 13:27 To: Pavan Kunapuli Cc: swarren at wwwdotorg.org; linux at arm.linux.org.uk; cjb at laptop.org; linux-tegra at vger.kernel.org; linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org; linux-mmc at vger.kernel.org Subject: Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails Am Dienstag, den 23.10.2012, 12:49 +0530 schrieb Pavan Kunapuli:
vmmc and vqmmc regulators control the voltage to the host and device. Defer the probe if either of them is not registered.
Does this work with boards where we don't have any MMC supplies? Or are we just deferring the probe indefinitely there? For boards that power MMC unconditionally, are we supposed to add dummy regulators to make them work with this patchset?
quoted hunk ↗ jump to hunk
Signed-off-by: Pavan Kunapuli <redacted> --- drivers/mmc/host/sdhci.c | 25 ++++++++++++++++++++++--- 1 files changed, 22 insertions(+), 3 deletions(-)diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index7922adb..925c403 100644--- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c@@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host) !(host->mmc->caps & MMC_CAP_NONREMOVABLE)) mmc->caps |= MMC_CAP_NEEDS_POLL; - /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */ + /* + * If vqmmc regulator and no 1.8V signalling, then there's no UHS. + * vqmmc regulator should be present. If it's not present, + * assume the regulator driver registration is not yet done and + * defer the probe. + */ host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc"); if (IS_ERR(host->vqmmc)) { - pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc)); + pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc)); host->vqmmc = NULL; + return -EPROBE_DEFER; } else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000)) regulator_enable(host->vqmmc);@@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host) ocr_avail = 0; + /* + * vmmc regulator should be present. If it's not present, + * assume the regulator driver registration is not yet done + * and defer the probe. + */ host->vmmc = regulator_get(mmc_dev(mmc), "vmmc"); if (IS_ERR(host->vmmc)) { - pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc)); + pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc)); host->vmmc = NULL; + ret = -EPROBE_DEFER; + goto vmmc_err; } else regulator_enable(host->vmmc);@@ -3121,7 +3134,13 @@ reset: untasklet: tasklet_kill(&host->card_tasklet); tasklet_kill(&host->finish_tasklet); +vmmc_err: + if (host->vqmmc) { + if (regulator_is_enabled(host->vqmmc)) + regulator_disable(host->vqmmc); + regulator_put(host->vqmmc); + } return ret; }