Re: [PATCH 13/13] HID: playstation: report DualSense hardware and firmware version.

On Sun, Dec 27, 2020 at 2:21 PM Roderick Colenbrander
[off-list ref] wrote:

Hi Barnabás,

Thanks for you great feedback.

On Sun, Dec 27, 2020 at 9:06 AM Barnabás Pőcze [off-list ref] wrote:

quoted

Hi


2020. december 19., szombat 7:23 keltezéssel, Roderick Colenbrander írta:

quoted

diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
index a55375ac79a9..2f989da906f3 100644
--- a/drivers/hid/hid-playstation.c
+++ b/drivers/hid/hid-playstation.c

[...]
+static ssize_t ps_show_firmware_version(struct device *dev,
+                             struct device_attribute
+                             *attr, char *buf)
+{
+     struct hid_device *hdev = to_hid_device(dev);
+     struct ps_device *ps_dev = hid_get_drvdata(hdev);
+
+     return snprintf(buf, PAGE_SIZE, "0x%08x\n", ps_dev->fw_version);

`sysfs_emit()` is preferred over *printf().

Thanks, I wasn't aware of its existence. Looks like it was added
recently, but yeah it is a lot nicer.

quoted

quoted

+}
+
+static DEVICE_ATTR(firmware_version, 0444, ps_show_firmware_version, NULL);
+
+static ssize_t ps_show_hardware_version(struct device *dev,
+                             struct device_attribute
+                             *attr, char *buf)
+{
+     struct hid_device *hdev = to_hid_device(dev);
+     struct ps_device *ps_dev = hid_get_drvdata(hdev);
+
+     return snprintf(buf, PAGE_SIZE, "0x%08x\n", ps_dev->hw_version);

Same here.

quoted

+}
[...]
+static int dualsense_get_firmware_info(struct dualsense *ds)
+{
+     uint8_t *buf;
+     int ret = 0;

Is there any reason it needs to be initialized?

quoted

+
+     buf = kzalloc(DS_FEATURE_REPORT_FIRMWARE_INFO_SIZE, GFP_KERNEL);
+     if (!buf)
+             return -ENOMEM;
+
+     ret = hid_hw_raw_request(ds->base.hdev, DS_FEATURE_REPORT_FIRMWARE_INFO, buf,
+                     DS_FEATURE_REPORT_FIRMWARE_INFO_SIZE, HID_FEATURE_REPORT,
+                     HID_REQ_GET_REPORT);
+     if (ret < 0)
+             goto err_free;
+
+     ds->base.hw_version = get_unaligned_le32(&buf[24]);
+     ds->base.fw_version = get_unaligned_le32(&buf[28]);

Shouldn't the size of the reply be checked?

Good point, I added a check and returning -EINVAL now in case of a
size mismatch.

quoted

quoted

+
+err_free:
+     kfree(buf);
+     return ret;
+}
+
 static int dualsense_get_mac_address(struct dualsense *ds)
 {
      uint8_t *buf;

@@ -1172,6 +1233,12 @@ static struct ps_device *dualsense_create(struct hid_device *hdev)
      }
      snprintf(hdev->uniq, sizeof(hdev->uniq), "%pMR", ds->base.mac_address);

+     ret = dualsense_get_firmware_info(ds);
+     if (ret < 0) {
+             hid_err(hdev, "Failed to get firmware info from DualSense\n");
+             return ERR_PTR(ret);
+     }
+
      ret = ps_devices_list_add((struct ps_device *)ds);
      if (ret < 0)
              return ERR_PTR(ret);

@@ -1241,6 +1308,12 @@ static struct ps_device *dualsense_create(struct hid_device *hdev)
      /* Set player LEDs to our player id. */
      dualsense_set_player_leds(ds);

+     /* Reporting hardware and firmware is important as there are frequent updates, which
+      * can change behavior.
+      */
+     hid_info(hdev, "Registered DualSense controller hw_version=%x fw_version=%x\n",
+                     ds->base.hw_version, ds->base.fw_version);
+
      return (struct ps_device *)ds;

 err:

@@ -1295,6 +1368,12 @@ static int ps_probe(struct hid_device *hdev, const struct hid_device_id *id)
              goto err_close;
      }

+     ret = sysfs_create_group(&hdev->dev.kobj, &ps_device_attribute_group);

It's a minor thing, but I think `device_{add,remove}_group()` would be better
here in the sense that it expresses the fact that the group is added to a device,
not just any object better.

Agreed, that's nicer I wasn't aware of it. I try to follow what other
hid drivers do and they all used the kobj directly, which honestly
felt nasty. Will change it to this.

Actually devm_device_add_group seems to be even nicer. Surprisingly it
isn't widely used yet.

Roderick