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Subject: Re: [PATCH 7/7] arm64: dts: qcom: sdm845: enable dma for spi
To:     Vinod Koul <vkoul@kernel.org>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Mark Brown <broonie@kernel.org>, Wolfram Sang <wsa@kernel.org>,
        linux-arm-msm@vger.kernel.org, Andy Gross <agross@kernel.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        Douglas Anderson <dianders@chromium.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Amit Pundir <amit.pundir@linaro.org>,
        linux-spi@vger.kernel.org, linux-i2c@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20210111151651.1616813-1-vkoul@kernel.org>
 <20210111151651.1616813-8-vkoul@kernel.org>
 <6cc90f43-f2c8-85f7-3d1c-f96468aab196@somainline.org>
 <20210111174649.GC2771@vkoul-mobl>
From:   Konrad Dybcio <konrad.dybcio@somainline.org>
Message-ID: <12aae061-3a7e-883f-9b82-0b608ccf9441@somainline.org>
Date:   Mon, 11 Jan 2021 21:45:03 +0100
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> If it is working without GPI enabled, it would work.. GPI for QUP is
> something that requires firmware and would have to be enabled by
> firmware


I think with the new code of yours:


mas->tx = dma_request_slave_channel(mas->dev, "tx");
+ if (IS_ERR_OR_NULL(mas->tx)) {
+ dev_err(mas->dev, "Failed to get tx DMA ch %ld", PTR_ERR(mas->tx)); ret = PTR_ERR(mas->tx); + goto out_pm;


it *may* fail to probe with the channels assigned in the "dmas=" property but with the engine having "status=disabled", but as I don't have any hardware to test that driver on, please confirm whether my concerns are right..


> Since DMA support may not be available on certain targets (firmware
> support), so enabling per board would make sense

Oh really, are there SDM845 boards shipping with GPI DMA *disabled to all peripherals*?


Konrad