Hi Boris,
> > >
> > > Re: [PATCH v3 2/4] mtd: rawnand: Add Macronix MX25F0A NAND
controller
> > >
> > > On Tue, 18 Jun 2019 08:14:36 +0200
> > > Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> wrote:
> > >
> > > > > > > > >
> > > > > > > > > How to make all #CS keep high for NAND to enter
> > > > > > > > > low-power standby mode if driver don't use
> > "legacy.select_chip()"
> > > > > ?
> > > > > > > >
> > > > > > > > See commit 02b4a52604a4 ("mtd: rawnand: Make
->select_chip()
> > > > > optional
> > > > > > > > when ->exec_op() is implemented") which states:
> > > > > > > >
> > > > > > > > "When [->select_chip() is] not implemented, the
core
> > is
> > > > > assuming
> > > > > > > > the CS line is automatically asserted/deasserted by the
> > driver
> > > > > > > > ->exec_op() implementation."
> > > > > > > >
> > > > > > > > Of course, the above is right only when the controller
driver
> >
> > > > > supports
> > > > > > > > the ->exec_op() interface.
> > > > > > >
> > > > > > > Currently, it seems that we will get the incorrect data and
> > error
> > > > > > > operation due to CS in error toggling if CS line is
controlled
> > in
> > > > > > > ->exec_op().
> > >
> > > Oh, and please provide the modifications you added on top of this
patch.
> > > Right now we're speculating on what you've done which is definitely
not
> > > an efficient way to debug this sort of issues.
> >
> > The patch is to add in beginning of ->exec_op() to control CS# low and
> > before return from ->exec_op() to control CS# High.
> > i.e,.
> > static in mxic_nand_exec_op( )
> > {
> > cs_to_low();
> >
> >
> >
> > cs_to_high();
> > return;
> > }
> >
> > But for nand_onfi_detect(),
> > it calls nand_read_param_page_op() and then nand_read_data_op().
> > mxic_nand_exec_op() be called twice for nand_onfi_detect() and
> > driver will get incorrect ONFI parameter table data from
> > nand_read_data_op().
>
> And I think it's valid to release the CE pin between
> read_param_page_op() (CMD(0xEC)+ADDR(0x0)) and read_data_op() (data
> cycles) if your chip is CE-dont-care compliant. So, either you have a
> problem with your controller driver (CS-related timings are incorrect)
> or your chip is not CE-dont-care compliant.
Understood, I will try to fix it on my NFC driver.
And I think CS# pin goes to high is much important for power consumption.
thanks & best regards,
Mason
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