From: Miquel Raynal <miquel.raynal@bootlin.com>
To: masonccyang@mxic.com.tw
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
christophe.kerello@st.com, bbrezillon@kernel.org,
juliensu@mxic.com.tw, lee.jones@linaro.org,
linux-kernel@vger.kernel.org, robh+dt@kernel.org,
linux-spi@vger.kernel.org, marcel.ziswiler@toradex.com,
paul.burton@mips.com, broonie@kernel.org, geert@linux-m68k.org,
stefan@agner.ch, linux-mtd@lists.infradead.org, richard@nod.at,
liang.yang@amlogic.com, computersforpeace@gmail.com,
dwmw2@infradead.org, marek.vasut@gmail.com,
zhengxunli@mxic.com.tw
Subject: Re: [PATCH v3 2/4] mtd: rawnand: Add Macronix MX25F0A NAND controller
Date: Mon, 27 May 2019 14:42:50 +0200 [thread overview]
Message-ID: <20190527144250.71908bd9@xps13> (raw)
In-Reply-To: <OFADC47344.0F9941B2-ON48258403.002336E3-48258403.003141F0@mxic.com.tw>
Hi Mason,
masonccyang@mxic.com.tw wrote on Thu, 23 May 2019 16:58:02 +0800:
> Hi Miquel,
>
> > >
> > > > > +
> > > > > +static void mxic_nand_select_chip(struct nand_chip *chip, int
> chipnr)
> > > >
> > > > _select_target() is preferred now
> > >
> > > Do you mean I implement mxic_nand_select_target() to control #CS ?
> > >
> > > If so, I need to call mxic_nand_select_target( ) to control #CS ON
> > > and then #CS OFF in _exec_op() due to nand_select_target()<in
> nand_base,c>
> > > is still calling chip->legacy.select_chip ?
> >
> > You must forget about the ->select_chip() callback. Now it should be
> > handled directly from the controller driver. Please have a look at the
> > commit pointed against the marvell_nand.c driver.
>
> I have no Marvell NFC datasheet and have one question.
>
> In marvell_nand.c, there is no xxx_deselect_target() or
> something like that doing #CS OFF.
> marvell_nfc_select_target() seems always to make one of chip or die
> #CS keep low.
>
> Is it right ?
Yes, AFAIR there is no "de-assert" mechanism in this controller.
>
> 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.
So if you think it is not too time consuming and worth the trouble to
assert/deassert the CS at each operation, you may do it in your driver.
Thanks,
Miquèl
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http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-05-27 12:43 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-15 9:23 [PATCH v3 0/4] Add Macronix MX25F0A MFD driver for raw nand and spi Mason Yang
2019-04-15 9:23 ` [PATCH v3 1/4] mfd: Add Macronix MX25F0A MFD controller driver Mason Yang
2019-05-12 13:08 ` Miquel Raynal
2019-05-15 6:46 ` masonccyang
2019-04-15 9:23 ` [PATCH v3 2/4] mtd: rawnand: Add Macronix MX25F0A NAND controller Mason Yang
2019-05-12 13:18 ` Miquel Raynal
2019-05-15 8:48 ` masonccyang
2019-05-15 12:08 ` Miquel Raynal
[not found] ` <OF8A566F14.A2F0F576-ON482583FB.002E7E32-482583FB.003068B1@LocalDomain>
2019-05-15 9:18 ` masonccyang
2019-05-17 9:30 ` masonccyang
2019-05-20 12:23 ` Miquel Raynal
2019-05-23 8:58 ` masonccyang
2019-05-27 12:42 ` Miquel Raynal [this message]
2019-05-29 3:12 ` masonccyang
2019-06-17 12:35 ` Miquel Raynal
2019-06-18 1:24 ` masonccyang
2019-06-18 6:14 ` Boris Brezillon
2019-06-18 7:29 ` Boris Brezillon
2019-06-19 8:04 ` masonccyang
2019-06-19 8:09 ` Miquel Raynal
2019-06-19 8:48 ` masonccyang
2019-06-24 9:05 ` masonccyang
2019-06-19 8:15 ` Boris Brezillon
2019-06-19 8:55 ` masonccyang
2019-06-19 9:06 ` Boris Brezillon
2019-06-24 8:55 ` masonccyang
2019-04-15 9:23 ` [PATCH v3 3/4] spi: Patch Macronix SPI controller driver according to MX25F0A MFD driver Mason Yang
2019-04-19 14:51 ` Mark Brown
[not found] ` <OF7742B4A9.445066F6-ON482583EC.0037E377-482583EC.0039125B@mxic.com.tw>
2019-05-02 2:41 ` Mark Brown
2019-04-15 9:23 ` [PATCH v3 4/4] dt-bindings: mfd: Document Macronix MX25F0A controller bindings Mason Yang
2019-04-26 22:41 ` Rob Herring
2019-05-12 13:23 ` Miquel Raynal
2019-05-15 7:36 ` masonccyang
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