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Date:   Fri, 23 Sep 2022 10:19:09 +0200
To:     Ivan Bornyakov <i.bornyakov@metrotek.ru>
Cc:     Xu Yilun <yilun.xu@intel.com>, mdf@kernel.org, hao.wu@intel.com,
        trix@redhat.com, dg@emlix.com, j.zink@pengutronix.de,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        linux-fpga@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel@pengutronix.de,
        system@metrotek.ru
Subject: Re: [PATCH v12 1/2] fpga: lattice-sysconfig-spi: add Lattice
 sysCONFIG FPGA manager
Message-ID: <20220923081909.GO986@pengutronix.de>
References: <20220919134750.25197-1-i.bornyakov@metrotek.ru>
 <20220919134750.25197-2-i.bornyakov@metrotek.ru>
 <Yy1RLvxTJhGUuJJ2@yilunxu-OptiPlex-7050>
 <20220923071638.45hylqvajn74j6mk@h-e2.ddg>
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In-Reply-To: <20220923071638.45hylqvajn74j6mk@h-e2.ddg>
User-Agent: Mutt/1.10.1 (2018-07-13)
From:   Sascha Hauer <sha@pengutronix.de>
Precedence: bulk

On Fri, Sep 23, 2022 at 10:16:38AM +0300, Ivan Bornyakov wrote:
> On Fri, Sep 23, 2022 at 02:24:46PM +0800, Xu Yilun wrote:
> > On 2022-09-19 at 16:47:49 +0300, Ivan Bornyakov wrote:
> > > Add support to the FPGA manager for programming Lattice ECP5 FPGA over
> > > slave SPI sysCONFIG interface.
> > > 
> > > sysCONFIG interface core functionality is separate from both ECP5 and
> > > SPI specifics, so support for other FPGAs with different port types can
> > > be added in the future.
> > > 
> > > Signed-off-by: Ivan Bornyakov <i.bornyakov@metrotek.ru>
> > > ---
> > >  drivers/fpga/Kconfig                 |  11 +
> > >  drivers/fpga/Makefile                |   2 +
> > >  drivers/fpga/lattice-sysconfig-spi.c | 153 ++++++++++
> > >  drivers/fpga/lattice-sysconfig.c     | 408 +++++++++++++++++++++++++++
> > >  drivers/fpga/lattice-sysconfig.h     |  40 +++
> > >  5 files changed, 614 insertions(+)
> > >  create mode 100644 drivers/fpga/lattice-sysconfig-spi.c
> > >  create mode 100644 drivers/fpga/lattice-sysconfig.c
> > >  create mode 100644 drivers/fpga/lattice-sysconfig.h
> > > 
> > > diff --git a/drivers/fpga/lattice-sysconfig-spi.c b/drivers/fpga/lattice-sysconfig-spi.c
> > > new file mode 100644
> > > index 000000000000..d015b796adf7
> > > --- /dev/null
> > > +++ b/drivers/fpga/lattice-sysconfig-spi.c
> > > 
> > > ... snip ...
> > > 
> > > +static int sysconfig_isc_enable(struct sysconfig_priv *priv)
> > > +{
> > > +	u8 isc_enable[] = SYSCONFIG_ISC_ENABLE;
> > > +	u32 status;
> > > +	int ret;
> > > +
> > > +	ret = sysconfig_cmd_write(priv, isc_enable, sizeof(isc_enable));
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = sysconfig_poll_status(priv, &status);
> > > +	if (ret || (status & SYSCONFIG_STATUS_FAIL))
> > > +		return ret ? : -EFAULT;
> > 
> > If (ret == 0 && status == SYSCONFIG_STATUS_FAIL), still return 0?
> > 
> 
> No, -EFAULT should be returned in that case. Am I overlooked something?

No, you don't, but writing this a bit less terse makes it far more
readable:

	ret = sysconfig_poll_status(priv, &status);
	if (ret)
		return ret;
	if (status & SYSCONFIG_STATUS_FAIL)
		return -EFAULT;

Sascha

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