Hello,
virtio-dev still down...
I have to admit when it comes to device trees it's most of the time a
fight. You will see below, fighting.
On 18.03.24 10:39, Haixu Cui wrote:
Hello,
As Mark recommended, I reserve the virtio_spi_probe function only
and list my comments.
On 3/4/2024 11:43 PM, Harald Mommer wrote:
+static int virtio_spi_probe(struct virtio_device *vdev)
+{
+ struct device_node *np = vdev->dev.parent->of_node;
+ struct virtio_spi_priv *priv;
+ struct spi_controller *ctrl;
+ int err;
+ u32 bus_num;
+ u16 csi;
+
+ ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv));
+ if (!ctrl)
+ return -ENOMEM;
+
+ priv = spi_controller_get_devdata(ctrl);
+ priv->vdev = vdev;
+ vdev->priv = priv;
+ dev_set_drvdata(&vdev->dev, ctrl);
ctrl->dev.of_node is not set, so the child node cannot be parsed.
I would say, it's necessary to support the virtio spi device node in
the format:
What you most probably want to have here is
ctrl->dev.of_node = np;
for reasons I don't understand completely yet but have some idea. I may
play around to get it.
virtio-spi@4b013000 {
compatible = "virtio,mmio";
reg = <0x4b013000 0x1000>;
interrupts = <0 497 4>;
spi {
compatible = "virtio,device2d";
#address-cells = <1>;
#size-cells = <0>;
spidev {
compatible = "xxx";
reg = <0>;
spi-max-frequency = <100000>;
};
};
};
Looks in my setup like this:
virtio_mmio@4b013000 {
compatible = "virtio,mmio";
reg = <0x0 0x4b013000 0x0 0x1000>;
/* GIC_SPI = 0, IRQ_TYPE_LEVEL_HIGH = 4 */
interrupts = <0 497 4>;
spi,bus-num = <1234>; /* <<<=== This here has been added */
};
The "spi,bus-num" is missing in your setup so you use the default of 0.
For what is "reg = <0>;" good? Or is it a dummy and only has to be present?
I don't understand spi-max-frequency in the device tree entry as we get
this value from the config space.
+
+ init_completion(&priv->spi_req.completion);
+
+ err = of_property_read_u32(np, "spi,bus-num", &bus_num);
np already set so this assignment should play no role here when reading
the entry.
+ if (!err && bus_num <= S16_MAX)
+ ctrl->bus_num = (s16)bus_num;
+
+ virtio_spi_read_config(vdev);
+
+ ctrl->transfer_one = virtio_spi_transfer_one;
+
+ err = virtio_spi_find_vqs(priv);
+ if (err) {
+ dev_err(&vdev->dev, "Cannot setup virtqueues\n");
+ return err;
+ }
+
+ err = spi_register_controller(ctrl);
+ if (err) {
+ dev_err(&vdev->dev, "Cannot register controller\n");
+ goto err_return;
+ }
+
+ board_info.max_speed_hz = priv->max_freq_hz;
+ /* spi_new_device() currently does not use bus_num but better
set it */
+ board_info.bus_num = (u16)ctrl->bus_num;
+
+ /* Add chip selects to controller */
Creating the spi devices here statically, will introduce
conflicts if the same spi devices also in the device-tree.
Of course I need to create the SPI devices here statically. The
"spi,bus-num = <1234>;" in the device tree has to be defined in a way
that there are no conflicts. I do not understand this.
+ 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))
+ 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;
+ }
+ }
+
+ return 0;
+
+err_return:
+ vdev->config->del_vqs(vdev);
+ return err;
+}
+
What I needed to support for our needs was a user space SPI interface.
You probably have a different setup and additional more complex device
tree configuration needs I do not understand (yet). I'm somewhat lost in
the moment.
