Hi York, > -----Original Message----- > From: York Sun [mailto:york....@nxp.com] > Sent: Thursday, April 20, 2017 11:22 AM > To: Peng Fan <peng....@nxp.com>; sba...@denx.de; > jh80.ch...@samsung.com > Cc: ota...@ossystems.com.br; u-boot@lists.denx.de > Subject: Re: [PATCH 1/4] mmc: fsl_esdhc: introduce vs18_enable for 1.8V fix > I/O > > On 04/19/2017 07:46 PM, Peng Fan wrote: > > When using eMMC with 1.8V I/O, the VSELECT bit need to be set in the > > USDHC controller when init. > > > > This patch adds a parameter "vs18_enable" in fsl_esdhc_cfg structure > > and priv data, so each controller can have different settings. > > > > We could not use CONFIG_SYS_FSL_ESDHC_FORCE_VSELECT, it has problem > > that it will apply to all USDHC controllers and it only set the 1.8V > > at init phase. So if user does not select to the eMMC device, the > > voltage on the I/O pins are not correct. > > > > Peng, > > I don't quite understand this. Isn't the voltage supplied by the board? > I believe we have detection on our boards to decide 3.3v or 1.8v should be > supplied. Does that have anything to do with the voltage you are talking > about? > I am referring to LS1046ARDB.
From i.MX6 RM, the VSELECT bit, Voltage Selection Change the value of output signal VSELECT, to control the voltage on pads for external card. There must be a control circuit out of uSDHC to change the voltage on pads. 1 Change the voltage to low voltage range, around 1.8 V 0 Change the voltage to high voltage range, around 3.0 V If the emmc vqmmc supply is 1.8V, the vselect must be set to 1. I am not sure if this is the case for LS family. Thanks, Peng. > > York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
