RE: [PATCH 06/10] spi: rzv2m-csi: Squash timing settings into one statement

From: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Mark Brown <broonie@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>
Subject: RE: [PATCH 06/10] spi: rzv2m-csi: Squash timing settings into one statement
Date: Mon, 17 Jul 2023 10:44:47 +0000	[thread overview]
Message-ID: <TYWPR01MB8775831C81B7153DB24F86C2C23BA@TYWPR01MB8775.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAHp75VdyUhvk9JA4oW6iYjK=YdatjG3OVa0APMQrc+un2EyadQ@mail.gmail.com>

Hi Andy,

Thanks for your reply.

> From: Andy Shevchenko <andy.shevchenko@gmail.com>
> Subject: Re: [PATCH 06/10] spi: rzv2m-csi: Squash timing settings into
> one statement
> 
> On Sat, Jul 15, 2023 at 4:04 AM Fabrizio Castro
> <fabrizio.castro.jz@renesas.com> wrote:
> >
> > Register CLKSEL hosts the configuration for both clock polarity
> > and data phase, and both values can be set in one write operation.
> >
> > Squash the clock polarity and data phase register writes into
> > one statement, for efficiency.
> 
> ...
> 
> >         /* Setup clock polarity and phase timing */
> > -       rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_CKP,
> > -                               !(spi->mode & SPI_CPOL));
> > -       rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_DAP,
> > -                               !(spi->mode & SPI_CPHA));
> > +       rzv2m_csi_reg_write_bit(csi, CSI_CLKSEL, CSI_CLKSEL_MODE,
> > +                               ~spi->mode & SPI_MODE_X_MASK);
> 
> I think this now regresses due to the absence of parentheses.

This looks okay to me. CSI_CLKSEL_CKP needs to contain the inverted value
of SPI_CPOL, and CSI_CLKSEL_DAP needs to contain the inverted value of
SPI_CPHA, and that happens with both use cases.

Thanks,
Fab

> 
> --
> With Best Regards,
> Andy Shevchenko