Hi, Harald
On Tue, Mar 26, 2024 at 12:28:12PM +0100, Harald Mommer wrote:
From: Harald Mommer <harald.mommer@xxxxxxxxxxxxxxx>[...]
This is the virtio SPI Linux kernel driver.
Signed-off-by: Harald Mommer <Harald.Mommer@xxxxxxxxxxxxxxx>
+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;
+ ctrl->dev.of_node = vdev->dev.of_node;
To support ACPI, ACPI node of the controller needs to be set:
/*
* Setup ACPI node for controlled devices which will be probed through
* ACPI.
*/
ACPI_COMPANION_SET(&vdev->dev, ACPI_COMPANION(vdev->dev.parent));
+ dev_set_drvdata(&vdev->dev, ctrl);
+
+ init_completion(&priv->spi_req.completion);
+
+ err = of_property_read_u32(np, "spi,bus-num", &bus_num);
+ if (!err && bus_num <= S16_MAX)
+ ctrl->bus_num = (s16)bus_num;
This is not the right way to fix bus number. You can use OF alias.
Also, to work with ACPI, we should use common API like
device_property_read_u32.
+How about ACPI path?
+ 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;
+ }
+
+ 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;
+
+ err = spi_register_controller(ctrl);
+ if (err) {
+ dev_err(&vdev->dev, "Cannot register controller\n");
+ goto err_return;
+ }
+
+ if (vdev->dev.of_node) {
+ dev_dbg(&vdev->dev, "Final setup triggered by DT child node\n");
+ return 0;
+ }
+Just enumerate SPI devices via DT/ACPI. And a fixed SPI modalias "spi-virtio"
+ /* Add chip selects to controller */
+ for (csi = 0; csi < ctrl->num_chipselect; csi++) {
+ dev_dbg(&vdev->dev, "Setting up CS=%u\n", csi);
+ board_info.chip_select = csi;
+
+ 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;
+ }
+ }
is no better than match method from DT/ACPI.
Thanks,
Qiang