[U-Boot] [PATCH 1/2] FSL/eSDHC: enable the peripheral clock to detect the card

[Huang Changming-R66093]

Thanks
Jerry Huang


> -----Original Message-----
> From: Stefano Babic [mailto:sbabic at denx.de]
> Sent: Wednesday, March 28, 2012 1:17 AM
> To: Dirk Behme
> Cc: Huang Changming-R66093; u-boot at lists.denx.de; Andy Fleming
> Subject: Re: [U-Boot] [PATCH 1/2] FSL/eSDHC: enable the peripheral clock
> to detect the card
> 
> On 27/03/2012 13:01, Dirk Behme wrote:
> > On 27.03.2012 12:25, Chang-Ming.Huang at freescale.com wrote:
> >> From: Jerry Huang <Chang-Ming.Huang at freescale.com>
> >>
> >> According to the card detection of p1/p2 paltform RM,
> >
> > typo => platform
> >
> >> we should set SYSCTL[PEREN] to enable the clock.
> >> Otherwise, after booting the u-boot, and then inserting the SD card,
> >> the SD card can't be detected.
> >>
> >> Signed-off-by: Jerry Huang <Chang-Ming.Huang at freescale.com>
> >> CC: Andy Fleming <afleming at gmail.com>
> >> ---
> >>  drivers/mmc/fsl_esdhc.c |    2 ++
> >>  1 files changed, 2 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c index
> >> a2f35e3..1682a79 100644
> >> --- a/drivers/mmc/fsl_esdhc.c
> >> +++ b/drivers/mmc/fsl_esdhc.c
> >> @@ -491,6 +491,8 @@ int fsl_esdhc_initialize(bd_t *bis, struct
> >> fsl_esdhc_cfg *cfg)
> >>      /* First reset the eSDHC controller */
> >>      esdhc_reset(regs);
> >>
> >> +    esdhc_write32(&regs->sysctl, SYSCTL_PEREN);
> >
> > If I read the iMX6 manual correctly, the SYSCTL_PEREN isn't
> > implemented there.
> 
> In the copy I could put my hands, SYSCTL_PEREN is implemented for i.MX6.
> However, I do not know if this has an influence. ESDHC should be clocked
> with SDCLKEN, that is enabled by default on i.MX (both MX5 and MX6).
> 
> > So this should be a NOP for iMX6?
> 
> However, if it is not implemented and it is marked as reserved, we should
> not set it.
> 
I.MX6/5 reuse the fsl_esdhc.c driver, and he don't care these reserved field.
Otherwise he should change this driver. E.g:
In function esdhc_init:
esdhc_write32(&regs->sysctl, SYSCTL_HCKEN | SYSCTL_IPGEN);
in function set_sysctl:
clk = SYSCTL_PEREN | SYSCTL_CKEN;
esdhc_setbits32(&regs->sysctl, clk);

so I think my code has no any problem.