Message-ID: <5554FDB4.50809@broadcom.com>
Date: Thu, 14 May 2015 12:55:32 -0700
From: Jonathan Richardson <jonathar@broadcom.com>
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/17.0 Thunderbird/17.0
MIME-Version: 1.0
To: Mark Brown <broonie@kernel.org>
CC: Scott Branden <sbranden@broadcom.com>, Dmitry Torokhov <dtor@google.com>,
        Anatol Pomazau <anatol@google.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-spi@vger.kernel.org>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@broadcom.com>,
        <devicetree@vger.kernel.org>
Subject: Re: [PATCH 2/2] spi: bcm-mspi: Add support for Broadcom MSPI driver.
References: <1431452293-16697-1-git-send-email-jonathar@broadcom.com> <1431452293-16697-3-git-send-email-jonathar@broadcom.com> <20150512191718.GW3066@sirena.org.uk> <5553E31A.8060309@broadcom.com> <5553E9FA.4070708@broadcom.com> <20150514103144.GO2761@sirena.org.uk> <5554E715.7070203@broadcom.com> <20150514190823.GR2761@sirena.org.uk>
In-Reply-To: <20150514190823.GR2761@sirena.org.uk>
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1841
Lines: 36

On 15-05-14 12:08 PM, Mark Brown wrote:
> On Thu, May 14, 2015 at 11:19:01AM -0700, Scott Branden wrote:
>> On 15-05-14 03:31 AM, Mark Brown wrote:
> 
>>> Chip vendors often say this sort of thing and then get surprised by what
>>> their users choose to do, and even if it only ever gets used with flash
>>> all it would take is some new flash command which can use full duplex
>>> for something.  Please write the code so it at least tries to handle
>>> full duplex operation, if you can't test it fully that's not the end of
>>> the world.  It doesn't look like it should be particularly difficult.
> 
>> Yes, there is always room for improvements in code.  In this case - it
>> really is not worth our time to add code we can't test.  We try to deliver
>> code that we can test and actually works.  Yes, if anyone needs to use the
> 
> While I try to not apply code that has obvious problems with silent data
> corruption in it which is what we have just now.
> 
>> mspi for full duplex operation code can be added in the future - it is
>> software.  This block has gone through many generations of our SoCs and has
>> only been used for this purpose - the bootROM boots from this SPI only.  It
>> is dedicated for this purpose.
> 
> All it takes is one hardware engineer who sees a SPI controller and a
> GPIO they can use for chip select; I wouldn't be so sure that nobody
> ever fixed this up locally (or happened to use a device that only needed
> single duplex).
> 

Hi Mark. Would it help if we just set the flags to half duplex using
SPI_MASTER_HALF_DUPLEX when we register the master?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/