From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH 05/12] mmc: sdhci: add a pre voltage switch callback function Date: Tue, 14 Jun 2016 10:07:06 +0300 Message-ID: <575FAD1A.6090407@intel.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; charset=gbk Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ziji Hu Cc: Gregory CLEMENT , Ulf Hansson , "linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Rob Herring , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Jason Cooper , Andrew Lunn , Sebastian Hesselbarth , Thomas Petazzoni , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Nadav Haklai , Victor Gu , Romain Perier , Omri Itach , Marcin Wojtas , Wilson Ding , Shadi Ammouri , Jisheng Zhang , "Wei(SOCP) Liu" List-Id: devicetree@vger.kernel.org On 13/06/16 17:04, Ziji Hu wrote: > Hi Adrian, >=20 > Thanks a lot for the suggestion. I'm from Marvell Xenon SDHC team. Mo= st > of sdhci host ops are still used in our driver. We just change or add= few > ops. Thus, if we create our own mmc_host_ops, many static sdhci host = ops > will be exported. I would like to know whether such a modification ca= n be > accepted or not. >=20 > I notice that community is improving sdhci. Thus all the static sdhci= ops > called outside the sdhci.c will be exported. Is my understanding > correct? Thank you. The aim is to make sdhci more like a library and give more control to t= he drivers. That will mean more sdhci functions get exported, particularl= y mmc host ops like sdhci_set_ios() or sdhci_start_signal_voltage_switch(). >=20 > Best regards, Hu Ziji >=20 >>> =D4=DA 2016=C4=EA6=D4=C213=C8=D5=A3=AC16:52=A3=ACAdrian Hunter =D0=B4=B5=C0=A3=BA >>>=20 >>> On 09/06/16 10:10, Gregory CLEMENT wrote: From: Victor Gu >>> >>>=20 >>> Some host controller such as Xenon needs additional setting when=20 >>> switching signal voltage in eMMC mode. They also need to re-enable=20 >>> internal clock before a voltage switch. >>>=20 >>> 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. >>=20 >> Don't want to add sdhci host ops for the "do something before a mmc >> host op" case. >>=20 >> Instead, export sdhci_start_signal_voltage_switch() and hook=20 >> host->mmc_host_ops.start_signal_voltage_switch. Then in sdhci-xenon.= c: >>=20 >> int xenon__start_signal_voltage_switch(struct mmc_host *mmc, struct >> mmc_ios *ios) { blah blah return sdhci_start_signal_voltage_switch(m= mc, >> ios); } >>=20 >>=20 >>>=20 >>> [gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org: split the initial commit and=20 >>> reformulate the log] >>>=20 >>> 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(+= ) >>>=20 >>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c=20 >>> 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; >>>=20 >>> + /* Some controller need to do more before switching */ + if >>> (host->ops->voltage_switch_pre) + >>> host->ops->voltage_switch_pre(host); + ctrl =3D sdhci_readw(host, >>> SDHCI_HOST_CONTROL2); >>>=20 >>> switch (ios->signal_voltage) { diff --git a/drivers/mmc/host/sdhci.= h >>> b/drivers/mmc/host/sdhci.h index 49c6c5b0e33b..6bec1b0368d2 100644=20 >>> --- 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); }; >>>=20 >>> #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS >>=20 >> -- To unsubscribe from this list: send the line "unsubscribe linux-m= mc" >> in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo >> info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html