From mboxrd@z Thu Jan 1 00:00:00 1970 From: Veerabhadrarao Badiganti Subject: Re: [PATCH V3 1/3] mmc: sdhci: Allow platform controlled voltage switching Date: Mon, 12 Nov 2018 22:49:36 +0530 Message-ID: References: <1539004739-32060-1-git-send-email-vbadigan@codeaurora.org> <1539004739-32060-2-git-send-email-vbadigan@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Evan Green Cc: adrian.hunter@intel.com, Ulf Hansson , robh+dt@kernel.org, Doug Anderson , asutoshd@codeaurora.org, riteshh@codeaurora.org, stummala@codeaurora.org, sayali , linux-mmc@vger.kernel.org, linux-arm-msm@vger.kernel.org, vviswana@codeaurora.org, linux-kernel@vger.kernel.org List-Id: linux-mmc@vger.kernel.org On 10/17/2018 3:39 AM, Evan Green wrote: > On Mon, Oct 8, 2018 at 6:22 AM Veerabhadrarao Badiganti > wrote: >> From: Vijay Viswanath >> >> Some controllers can have internal mechanism to inform the SW that it >> is ready for voltage switching. For such controllers, changing voltage >> before the HW is ready can result in various issues. >> >> During setup/cleanup of host, check whether regulator enable/disable >> was already done by platform driver. >> >> Signed-off-by: Vijay Viswanath >> Signed-off-by: Veerabhadrarao Badiganti >> --- >> drivers/mmc/host/sdhci.c | 32 +++++++++++++++++++------------- >> drivers/mmc/host/sdhci.h | 1 + >> 2 files changed, 20 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >> index 99bdae5..ea7ce1d 100644 >> --- a/drivers/mmc/host/sdhci.c >> +++ b/drivers/mmc/host/sdhci.c >> @@ -3616,6 +3616,7 @@ int sdhci_setup_host(struct sdhci_host *host) >> unsigned int override_timeout_clk; >> u32 max_clk; >> int ret; >> + bool enable_vqmmc = false; >> >> WARN_ON(host == NULL); >> if (host == NULL) >> @@ -3629,9 +3630,12 @@ int sdhci_setup_host(struct sdhci_host *host) >> * the host can take the appropriate action if regulators are not >> * available. >> */ >> - ret = mmc_regulator_get_supply(mmc); >> - if (ret) >> - return ret; >> + if (!mmc->supply.vqmmc) { >> + ret = mmc_regulator_get_supply(mmc); >> + if (ret) >> + return ret; >> + enable_vqmmc = true; >> + } > Did you not like my suggestion in the previous patch of changing > mmc_regulator_get_supply to only get supplies that were not set > previously? What you have here is almost the same, except you've got > this weird coupling where if vqmmc is already present, you implicitly > skip looking at vmmc entirely (since mmc_regulator_get_supply does > more than just get vqmmc). sure. Will update mmc_regulator_get_supply() as you suggested. >> DBG("Version: 0x%08x | Present: 0x%08x\n", >> sdhci_readw(host, SDHCI_HOST_VERSION), >> @@ -3880,7 +3884,15 @@ int sdhci_setup_host(struct sdhci_host *host) >> mmc->caps |= MMC_CAP_NEEDS_POLL; >> >> if (!IS_ERR(mmc->supply.vqmmc)) { >> - ret = regulator_enable(mmc->supply.vqmmc); >> + if (enable_vqmmc) { >> + ret = regulator_enable(mmc->supply.vqmmc); >> + if (ret) { >> + pr_warn("%s: Failed to enable vqmmc regulator: %d\n", >> + mmc_hostname(mmc), ret); >> + mmc->supply.vqmmc = ERR_PTR(-EINVAL); >> + } >> + host->vqmmc_enabled = !ret; >> + } >> >> /* If vqmmc provides no 1.8V signalling, then there's no UHS */ >> if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000, >> @@ -3893,12 +3905,6 @@ int sdhci_setup_host(struct sdhci_host *host) >> 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); >> - mmc->supply.vqmmc = ERR_PTR(-EINVAL); >> - } >> } >> >> if (host->quirks2 & SDHCI_QUIRK2_NO_1_8_V) { >> @@ -4136,7 +4142,7 @@ int sdhci_setup_host(struct sdhci_host *host) >> return 0; >> >> unreg: >> - if (!IS_ERR(mmc->supply.vqmmc)) >> + if (host->vqmmc_enabled) >> regulator_disable(mmc->supply.vqmmc); >> undma: >> if (host->align_buffer) >> @@ -4154,7 +4160,7 @@ void sdhci_cleanup_host(struct sdhci_host *host) >> { >> struct mmc_host *mmc = host->mmc; >> >> - if (!IS_ERR(mmc->supply.vqmmc)) >> + if (host->vqmmc_enabled) >> regulator_disable(mmc->supply.vqmmc); >> >> if (host->align_buffer) >> @@ -4287,7 +4293,7 @@ void sdhci_remove_host(struct sdhci_host *host, int dead) >> >> tasklet_kill(&host->finish_tasklet); >> >> - if (!IS_ERR(mmc->supply.vqmmc)) >> + if (host->vqmmc_enabled) >> regulator_disable(mmc->supply.vqmmc); >> >> if (host->align_buffer) >> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h >> index b001cf4..3c28152 100644 >> --- a/drivers/mmc/host/sdhci.h >> +++ b/drivers/mmc/host/sdhci.h >> @@ -524,6 +524,7 @@ struct sdhci_host { >> bool pending_reset; /* Cmd/data reset is pending */ >> bool irq_wake_enabled; /* IRQ wakeup is enabled */ >> bool v4_mode; /* Host Version 4 Enable */ >> + bool vqmmc_enabled; /* Vqmmc is enabled */ > I still don't love this, since it doesn't mean what it says. Everyone > else that has a vqmmc_enabled member uses it to actually mean "vqmmc > is enabled", but this doesn't mean that. For example, you don't clear > this when you disable the regulator in patch 3, so this would be set > even if the regulator is disabled, and you don't set it when sdhci > enables the regulator, so the regulator is on when this flag is not > set. > > At the very least, I think a rename is in order. I'm struggling with > the rename, since > "vqmmc_pltfrm_enable_but_feel_free_to_call_set_voltage_anywhere" is > too long. I guess vqmmc_pltfrm_enabled is the best I've got for now. Sure. Will rename it. >> struct mmc_request *mrqs_done[SDHCI_MAX_MRQS]; /* Requests done */ >> struct mmc_command *cmd; /* Current command */ >> -- >> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project. >>