From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gregory CLEMENT Subject: Re: [PATCH 05/12] mmc: sdhci: add a pre voltage switch callback function Date: Tue, 14 Jun 2016 09:59:52 +0200 Message-ID: <87h9cwci9z.fsf@free-electrons.com> References: <1465456218-28354-1-git-send-email-gregory.clement@free-electrons.com> <1465456218-28354-6-git-send-email-gregory.clement@free-electrons.com> <575E72DC.5090604@intel.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <575E72DC.5090604@intel.com> (Adrian Hunter's message of "Mon, 13 Jun 2016 11:46:20 +0300") Sender: linux-mmc-owner@vger.kernel.org To: Adrian Hunter Cc: Ulf Hansson , linux-mmc@vger.kernel.org, Rob Herring , devicetree@vger.kernel.org, Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Thomas Petazzoni , linux-arm-kernel@lists.infradead.org, Nadav Haklai , Victor Gu , Romain Perier , Omri Itach , Marcin Wojtas , Wilson Ding , Shadi Ammouri List-Id: devicetree@vger.kernel.org Hi Adrian, On lun., juin 13 2016, Adrian Hunter wrote: > On 09/06/16 10:10, Gregory CLEMENT wrote: >> From: Victor Gu >> >> Some host controller such as Xenon needs additional setting when >> switching signal voltage in eMMC mode. They also need to re-enable >> internal clock before a voltage switch. >> >> This commit adds a callback routine "voltage_switch_pre" in the struct >> sdhci_ops, which is used by some host controllers which need re-enable >> the internal clock before a voltage switch. > > Don't want to add sdhci host ops for the "do something before a mmc host op" > case. > > Instead, export sdhci_start_signal_voltage_switch() and hook > host->mmc_host_ops.start_signal_voltage_switch. Then in sdhci-xenon.c: > > int xenon__start_signal_voltage_switch(struct mmc_host *mmc, > struct mmc_ios *ios) > { > blah blah > return sdhci_start_signal_voltage_switch(mmc, ios); > } OK I see your point. Thanks, Gregory > > >> >> [gregory.clement@free-electrons.com: split the initial commit and >> reformulate the log] >> >> Signed-off-by: Victor Gu >> Signed-off-by: Marcin Wojtas >> Signed-off-by: Gregory CLEMENT >> --- >> drivers/mmc/host/sdhci.c | 4 ++++ >> drivers/mmc/host/sdhci.h | 1 + >> 2 files changed, 5 insertions(+) >> >> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >> index b07219426d39..cad03ffa9d9b 100644 >> --- a/drivers/mmc/host/sdhci.c >> +++ b/drivers/mmc/host/sdhci.c >> @@ -1729,6 +1729,10 @@ static int sdhci_start_signal_voltage_switch(struct mmc_host *mmc, >> if (host->version < SDHCI_SPEC_300) >> return 0; >> >> + /* Some controller need to do more before switching */ >> + if (host->ops->voltage_switch_pre) >> + host->ops->voltage_switch_pre(host); >> + >> ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2); >> >> switch (ios->signal_voltage) { >> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h >> index 49c6c5b0e33b..6bec1b0368d2 100644 >> --- a/drivers/mmc/host/sdhci.h >> +++ b/drivers/mmc/host/sdhci.h >> @@ -550,6 +550,7 @@ struct sdhci_ops { >> unsigned int max_dtr, int host_drv, >> int card_drv, int *drv_type); >> void (*init_card)(struct sdhci_host *host, struct mmc_card *card); >> + void (*voltage_switch_pre)(struct sdhci_host *host); >> }; >> >> #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS >> > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com