linux-kernel - Re: [linux-sunxi] [PATCH v3 10/13] spi: sunxi: merge sun4i and sun6i SPI driver

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Date:	Tue, 14 Jun 2016 06:34:45 +0200
From:	Michal Suchanek <hramrach@...il.com>
To:	Julian Calaby <julian.calaby@...il.com>
Cc:	linux-sunxi <linux-sunxi@...glegroups.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Chen-Yu Tsai <wens@...e.org>,
	Russell King <linux@...linux.org.uk>,
	Mark Brown <broonie@...nel.org>, Arnd Bergmann <arnd@...db.de>,
	Olof Johansson <olof@...om.net>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Simon Horman <horms+renesas@...ge.net.au>,
	Sjoerd Simons <sjoerd.simons@...labora.co.uk>,
	Thierry Reding <treding@...dia.com>,
	Alison Wang <b18965@...escale.com>,
	Timo Sigurdsson <public_timo.s@...entcreek.de>,
	Jonathan Liu <net147@...il.com>,
	Gerhard Bertelsmann <info@...hard-bertelsmann.de>,
	Priit Laes <plaes@...es.org>,
	devicetree <devicetree@...r.kernel.org>,
	"Mailing List, Arm" <linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-spi <linux-spi@...r.kernel.org>
Subject: Re: [linux-sunxi] [PATCH v3 10/13] spi: sunxi: merge sun4i and sun6i
 SPI driver

Hello,

On 14 June 2016 at 01:43, Julian Calaby <julian.calaby@...il.com> wrote:
> Hi Michal,
>
> On Tue, Jun 14, 2016 at 3:46 AM, Michal Suchanek <hramrach@...il.com> wrote:
>> The drivers are very similar and share multiple flaws which needed
>> separate fixes for both drivers.
>>
>> Signed-off-by: Michal Suchanek <hramrach@...il.com>
>> ---
>>  drivers/spi/Kconfig     |   8 +-
>>  drivers/spi/Makefile    |   1 -
>>  drivers/spi/spi-sun4i.c | 156 +++++++++++--
>>  drivers/spi/spi-sun6i.c | 598 ------------------------------------------------
>>  4 files changed, 143 insertions(+), 620 deletions(-)
>>  delete mode 100644 drivers/spi/spi-sun6i.c
>>
>> diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
>> index 0b8e6c6..c76f8e4 100644
>> --- a/drivers/spi/spi-sun4i.c
>> +++ b/drivers/spi/spi-sun4i.c
>> @@ -279,9 +321,14 @@ static int sunxi_spi_transfer_one(struct spi_master *master,
>>         reg = sunxi_spi_read(sspi, SUNXI_TFR_CTL_REG);
>>
>>         /* Reset FIFOs */
>> -       sunxi_spi_write(sspi, SUNXI_TFR_CTL_REG,
>> -                       reg | sspi_bits(sspi, SUNXI_CTL_RF_RST) |
>> -                       sspi_bits(sspi, SUNXI_CTL_TF_RST));
>> +       if (sspi->type == SPI_SUN4I)
>> +               sunxi_spi_write(sspi, SUNXI_TFR_CTL_REG,
>> +                               reg | sspi_bits(sspi, SUNXI_CTL_RF_RST) |
>> +                               sspi_bits(sspi, SUNXI_CTL_TF_RST));
>> +       else
>> +               sunxi_spi_write(sspi, SUNXI_FIFO_CTL_REG,
>> +                               sspi_bits(sspi, SUNXI_CTL_RF_RST) |
>> +                               sspi_bits(sspi, SUNXI_CTL_TF_RST));
>
> If we're already doing different stuff for each generation of the IP,
> why not just use the register offsets and bit definitions directly?

Because having (*sspi->regmap)[SUNXI_FIFO_CTL_REG] all over the place
makes my eyes bleed and you cannot use the check that you are
accessing a register that actually exists.

>> @@ -491,10 +558,37 @@ static int sunxi_spi_probe(struct platform_device *pdev)
>>         }
>>
>>         sspi->master = master;
>> -       sspi->fifo_depth = SUN4I_FIFO_DEPTH;
>> -       sspi->type = SPI_SUN4I;
>> -       sspi->regmap = &sun4i_regmap;
>> -       sspi->bitmap = &sun4i_bitmap;
>> +       if (of_device_is_compatible(pdev->dev.of_node, SUN4I_COMPATIBLE)) {
>> +               sspi->fifo_depth = SUN4I_FIFO_DEPTH;
>> +               sspi->type = SPI_SUN4I;
>> +               sspi->regmap = &sun4i_regmap;
>> +               sspi->bitmap = &sun4i_bitmap;
>> +       } else if (of_device_is_compatible(pdev->dev.of_node,
>> +                                          SUN6I_COMPATIBLE)) {
>> +               sspi->fifo_depth = SUN6I_FIFO_DEPTH;
>> +               sspi->type = SPI_SUN6I;
>> +               sspi->regmap = &sun6i_regmap;
>> +               sspi->bitmap = &sun6i_bitmap;
>
> Can you store data in the match table instead of doing this?

That might be nicer. Will look into this.

Thanks

Michal