From: "Rafał Miłecki" <zajec5@gmail.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
Jonathan Richardson <jonathar@broadcom.com>,
Mark Brown <broonie@kernel.org>,
Dmitry Torokhov <dtor@google.com>,
Anatol Pomazau <anatol@google.com>,
Scott Branden <sbranden@broadcom.com>,
Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-spi <linux-spi@vger.kernel.org>,
bcm-kernel-feedback-list <bcm-kernel-feedback-list@broadcom.com>,
devicetree <devicetree@vger.kernel.org>
Subject: Re: [PATCH 3/4] spi: bcm-mspi: Make BCMA optional to support non-BCMA chips
Date: Mon, 6 Apr 2015 12:36:11 +0200 [thread overview]
Message-ID: <CACna6ry9qxzY9xaaqR8K6XgSEun31c=d1XrWH_vk7Fq7fJTxoA@mail.gmail.com> (raw)
In-Reply-To: <551ED345.1000702@gmail.com>
On 3 April 2015 at 19:52, Florian Fainelli <f.fainelli@gmail.com> wrote:
> On 03/04/15 06:38, Andy Shevchenko wrote:
>> On Thu, Apr 2, 2015 at 10:23 PM, Jonathan Richardson
>> <jonathar@broadcom.com> wrote:
>>> The Broadcom MSPI controller is used on various chips. The driver only
>>> supported BCM53xx chips with BCMA (an AMBA bus variant). The driver is
>>> refactored to make BCMA optional and provides a new config for non BCMA
>>> systems.
>>
>>> struct bcm_mspi {
>>> + #ifdef CONFIG_SPI_BCMA_MSPI
>>> struct bcma_device *core;
>>> - struct spi_master *master;
>>> + #endif
>>>
>>> + void __iomem *base;
>>> + struct spi_master *master;
>>> size_t read_offset;
>>
>>> + void (*mspi_write)(struct bcm_mspi *mspi, u16 offset, u32 value);
>>> + u32 (*mspi_read)(struct bcm_mspi *mspi, u16 offset);
>>> +};
>>
>> To avoid ugly ifdefs I think better to split driver to core part and
>> the actual driver part, at the end you will have something like
>> mspi-core.c mspi-53xx.c mspi-whatever.c. Check for example spi-dw*.c
>
> Actually, I am really curious whether we need the special BCMA I/O
> accessors in the first place, cannot we just access the MSPI core on
> BCM53xx chips using regular MMIO? That would probably solve the
> "problem" entirely. Rafal, did you try this before?
It's a matter of choice between:
1) Using one design for all bcma users
2) Using one design for all bcm-mspi users
I believe no matter which one you choose, you'll break another one.
If you take a look at drivers/bcma/host_soc.c, you'll see we've there
core->io_addr. I guess you could use it as the base in bcm-mspi. That
of course will make you a bit less compatible with other bcma drivers
(skipping bcma R/W layer).
> As for splitting the driver into a "library" driver which is mostly
> independent from the bus and a bus-specific wrapper, I think BCMA is
> really the only special case here, which is why I suggested earlier to
> Jonathan that we might just prefer ifdefing things out instead of
> creating a separate layer just for BCMA.
I think you may be right, this #if for bcma shouldn't be that bad and
it shouldn't grow in the future.
Still, I'd like to get this patch split nicely to review independent changes.
--
Rafał
next prev parent reply other threads:[~2015-04-06 10:36 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-02 19:23 [PATCH 0/4] Add MSPI support for Cygnus Jonathan Richardson
2015-04-02 19:23 ` [PATCH 1/4] ARM: dts: Add binding for Broadcom MSPI driver Jonathan Richardson
2015-04-04 19:17 ` Florian Fainelli
2015-04-06 18:45 ` Jonathan Richardson
2015-04-02 19:23 ` [PATCH 2/4] spi: bcm53xx: Refactor to make driver nonspecific to 53xx SoCs Jonathan Richardson
2015-04-03 13:35 ` Andy Shevchenko
2015-04-06 10:18 ` Rafał Miłecki
2015-04-06 18:58 ` Jonathan Richardson
2015-04-06 18:30 ` Jonathan Richardson
2015-04-07 8:03 ` Andy Shevchenko
2015-04-02 19:23 ` [PATCH 3/4] spi: bcm-mspi: Make BCMA optional to support non-BCMA chips Jonathan Richardson
2015-04-03 13:38 ` Andy Shevchenko
2015-04-03 17:52 ` Florian Fainelli
2015-04-06 10:36 ` Rafał Miłecki [this message]
2015-04-06 19:09 ` Jonathan Richardson
2015-04-06 18:39 ` Jonathan Richardson
2015-04-06 10:26 ` Rafał Miłecki
2015-04-06 10:26 ` Rafał Miłecki
2015-04-02 19:23 ` [PATCH 4/4] spi: bcm-mspi: Add support to set serial baud clock rate Jonathan Richardson
2015-04-04 19:12 ` Florian Fainelli
2015-04-06 9:46 ` Mark Brown
2015-04-06 18:54 ` Jonathan Richardson
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