From: Harald Mommer <harald.mommer@opensynergy.com>
To: Haixu Cui <quic_haixcui@quicinc.com>,
Viresh Kumar <viresh.kumar@linaro.org>
Cc: Mark Brown <broonie@kernel.org>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
quic_ztu@quicinc.com, Matti Moell <Matti.Moell@opensynergy.com>,
Mikhail Golubev <Mikhail.Golubev@opensynergy.com>
Subject: Re: [PATCH v2 3/3] virtio-spi: Add virtio SPI driver.
Date: Tue, 26 Mar 2024 12:19:06 +0100 [thread overview]
Message-ID: <c0647197-5c87-4154-8a50-92e7dd2297ec@opensynergy.com> (raw)
In-Reply-To: <8fbb904c-8d24-4d00-bff8-65f1e4bad5bb@quicinc.com>
Hello,
On 26.03.24 10:26, Haixu Cui wrote:
>
>> Looking at how i2c-virtio does it, it should be tied to the device
>> itself
>> instead of its parent:
>
> Yes, it is
> ctrl->dev.of_node = vdev->dev.of_node;
got it when looking into Viresh's code changes.
>>
>> Right, some work was done in the past to standardize these compatibles:
>>
>> $ git log -p --stat --reverse 0d8c9e7d4b40..694a1116b405
>>
> Here I would like the inner layer "spidev", to match then probe
> the spidev driver, the "reg" is the chip select index.
> "spi-max-frequency" is not necessary, while It doesn't matter.
>
> You can also customize the inner layer to match your own driver.
>
> In my test, I set the cs max number as 1, and in device tree node
> inner layer, reg as 0. So certainly spidev driver probed and spidev0.0
> is added successfully.
>
> But then the driver proceed to the following code, chip select
> index 0 device is created again, the driver fail with log: "chipselect
> 0 already in use".
The following lines
board_info.max_speed_hz = priv->max_freq_hz;
board_info.bus_num = (u16)ctrl->bus_num;
if (!(priv->mode_func_supported & VIRTIO_SPI_CS_HIGH))
board_info.mode = SPI_MODE_0;
else
board_info.mode = SPI_MODE_0 | SPI_CS_HIGH;
are moved before the sequence
err = spi_register_controller(ctrl);
if (err) {
dev_err(&vdev->dev, "Cannot register controller\n");
goto err_return;
}
if (vdev->dev.of_node) { // <=== This block is new
dev_dbg(&vdev->dev, "Final setup triggered by DT child node\n");
return 0;
}
>
> for (csi = 0; csi < ctrl->num_chipselect; csi++) {
> dev_dbg(&vdev->dev, "Setting up CS=%u\n", csi);
> board_info.chip_select = csi;
>
> if (!(priv->mode_func_supported & VIRTIO_SPI_CS_HIGH)) //
> <=== This if else is moved up. It is csi invariant anyway.
> board_info.mode = SPI_MODE_0;
> else
> board_info.mode = SPI_MODE_0 | SPI_CS_HIGH;
>
> if (!spi_new_device(ctrl, &board_info)) {
> dev_err(&vdev->dev, "Cannot setup device %u\n", csi);
> spi_unregister_controller(ctrl);
> err = -ENODEV;
> goto err_return;
> }
> }
>
>
This means when there is no device tree entry everything behaves as
before (for loop executed) and if there is a device tree entry the chip
select will be setup already by spi_register_controller() and the for
loop need not and will not be executed not annoying anyone with
"chipselect 0 already in use".
I was undecided whether to keep Viresh Kumar's "reviewed by" in the
commit message because I'm unsure whether this is to be considered as a
substantial change. Changes are small but program logic is changed (vs.
change of comment, removal of trace, change of trace wording) so I think
it may be considered as a substantial change and therefore I'll remove
the "reviewed-by" now.
prev parent reply other threads:[~2024-03-26 11:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-04 15:43 [PATCH v2 0/3] Virtio SPI Linux driver Harald Mommer
2024-03-04 15:43 ` [PATCH v2 1/3] virtio: Add ID for virtio SPI Harald Mommer
2024-03-04 15:43 ` [PATCH v2 2/3] virtio-spi: Add virtio-spi.h Harald Mommer
2024-03-04 15:43 ` [PATCH v2 3/3] virtio-spi: Add virtio SPI driver Harald Mommer
2024-03-14 9:17 ` Haixu Cui
2024-03-14 13:35 ` Mark Brown
2024-03-18 9:39 ` Haixu Cui
2024-03-19 15:05 ` Harald Mommer
2024-03-19 17:11 ` Mark Brown
2024-03-20 3:12 ` Viresh Kumar
2024-03-26 9:26 ` Haixu Cui
2024-03-26 11:19 ` Harald Mommer [this message]
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