Le 23/06/2023 à 13:01, Johannes Roith a écrit :
Added a gpiochip compatible driver to control the 8 GPIOs of the MCP2200
by using the HID interface.
Using GPIOs with alternative functions (GP0<->SSPND, GP1<->USBCFG,
GP6<->RXLED, GP7<->TXLED) will reset the functions, if set (unset by
default).
The driver was tested while also using the UART of the chip. Setting
and reading the GPIOs has no effect on the UART communication. However,
a reset is triggered after the CONFIGURE command. If the GPIO Direction
is constantly changed, this will affect the communication at low baud
rates. This is a hardware problem of the MCP2200 and is not caused by
the driver.
Feedback from reviewers Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
and Andi Shyti <andi.shyti@xxxxxxxxxx> was added.
Signed-off-by: Johannes Roith <johannes@gnu-linux.rocks>
---
[...]
+static int mcp2200_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+ int ret;
+ struct mcp2200 *mcp;
+
+ mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
+ if (!mcp)
+ return -ENOMEM;
+
+ ret = hid_parse(hdev);
+ if (ret) {
+ hid_err(hdev, "can't parse reports\n");
+ return ret;
+ }
+
+ /*
+ * This driver uses the .raw_event callback and therefore does not need any
+ * HID_CONNECT_xxx flags.
+ */
+ ret = hid_hw_start(hdev, 0);
+ if (ret) {
+ hid_err(hdev, "can't start hardware\n");
+ return ret;
+ }
+
+ hid_info(hdev, "USB HID v%x.%02x Device [%s] on %s\n", hdev->version >> 8,
+ hdev->version & 0xff, hdev->name, hdev->phys);
+
+ ret = hid_hw_open(hdev);
+ if (ret) {
+ hid_err(hdev, "can't open device\n");
+ hid_hw_stop(hdev);
+ return ret;
+ }
+
+ mutex_init(&mcp->lock);
+ init_completion(&mcp->wait_in_report);
+ hid_set_drvdata(hdev, mcp);
+ mcp->hdev = hdev;
+
+ ret = devm_add_action_or_reset(&hdev->dev, mcp2200_hid_unregister, hdev);
+ if (ret)
+ return ret;
+
+ mcp->gc = template_chip;
+ mcp->gc.parent = &hdev->dev;
+
+ ret = gpiochip_add_data(&mcp->gc, mcp);
devm_gpiochip_add_data()?
+ if (ret < 0) {
+ dev_err(&hdev->dev, "Unable to register gpiochip\n");
hid_err() to be consistent?
+ hid_hw_stop(hdev);
Isn't it already run by mcp2200_hid_unregister() registered a few lines
above?
CJ
+ return ret;
+ }
+
+ return 0;
+}
+
+static void mcp2200_remove(struct hid_device *hdev)
+{
+ struct mcp2200 *mcp;
+
+ mcp = hid_get_drvdata(hdev);
+ gpiochip_remove(&mcp->gc);
+}
+
[...]
