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Date:   Wed, 12 Apr 2023 22:57:48 +0530
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Subject: Re: [PATCH 2/2] spi: spi-qcom-qspi: Add DMA mode support
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To:     Mark Brown <broonie@kernel.org>
CC:     <agross@kernel.org>, <andersson@kernel.org>,
        <konrad.dybcio@linaro.org>, <robh+dt@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <vkoul@kernel.org>,
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        <linux-kernel@vger.kernel.org>, <linux-spi@vger.kernel.org>,
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        <mka@chromium.org>, <swboyd@chromium.org>,
        <quic_vtanuku@quicinc.com>
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From:   Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
In-Reply-To: <af2db163-9ab2-4efc-af55-933d2cc4c747@sirena.org.uk>
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On 4/12/2023 9:42 PM, Mark Brown wrote:
> On Wed, Apr 12, 2023 at 08:59:06PM +0530, Vijaya Krishna Nivarthi wrote:
>> On 4/6/2023 8:58 PM, Mark Brown wrote:
>>>>>> +	if (ctrl->xfer.dir == QSPI_READ)
>>>>>> +		byte_ptr = (uint8_t *)xfer->rx_buf;
>>>>>> +	else
>>>>>> +		byte_ptr = (uint8_t *)xfer->tx_buf;
>>>>> If we need to cast to or from void * there's some sort of problem.
>>>> the tx_buf is a const void*
>>>> in v2 I will cast for tx_buf only?
>>> Or just keep byte_ptr as const - we're not modifying it are we?
>> We are modifying it, hence did cast for tx_buf only
> If it's being modified won't that upset the callers that thought it was
> const and didn't expect the data to change?

I believe callers wouldn't be upset.

The byte_ptr is being modified (incremented)

It is initialised to tx_buf (a const*) and keeps getting incremented to 
parse data.

No data change.

That should be ok?