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Subject[PATCH v5 2/4] HID: steam: add serial number information.
Date
This device has a feature report to send and receive commands.
Use it to get the serial number and set the device's uniq value.

Signed-off-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
---
drivers/hid/hid-steam.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 105 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
index bc8b706311a9..03eebc4c28ba 100644
--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c
@@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/rcupdate.h>
+#include <linux/delay.h>
#include "hid-ids.h"

MODULE_LICENSE("GPL");
@@ -25,6 +26,7 @@ MODULE_AUTHOR("Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>");

#define STEAM_QUIRK_WIRELESS BIT(0)

+#define STEAM_SERIAL_LEN 10
/* Touch pads are 40 mm in diameter and 65535 units */
#define STEAM_PAD_RESOLUTION 1638
/* Trigger runs are about 5 mm and 256 units */
@@ -41,8 +43,102 @@ struct steam_device {
unsigned long quirks;
struct work_struct work_connect;
bool connected;
+ char serial_no[STEAM_SERIAL_LEN + 1];
};

+static int steam_recv_report(struct steam_device *steam,
+ u8 *data, int size)
+{
+ struct hid_report *r;
+ u8 *buf;
+ int ret;
+
+ r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
+ if (hid_report_len(r) < 64)
+ return -EINVAL;
+
+ buf = hid_alloc_report_buf(r, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ /*
+ * The report ID is always 0, so strip the first byte from the output.
+ * hid_report_len() is not counting the report ID, so +1 to the length
+ * or else we get a EOVERFLOW. We are safe from a buffer overflow
+ * because hid_alloc_report_buf() allocates +7 bytes.
+ */
+ ret = hid_hw_raw_request(steam->hdev, 0x00,
+ buf, hid_report_len(r) + 1,
+ HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+ if (ret > 0)
+ memcpy(data, buf + 1, min(size, ret - 1));
+ kfree(buf);
+ return ret;
+}
+
+static int steam_send_report(struct steam_device *steam,
+ u8 *cmd, int size)
+{
+ struct hid_report *r;
+ u8 *buf;
+ unsigned int retries = 10;
+ int ret;
+
+ r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
+ if (hid_report_len(r) < 64)
+ return -EINVAL;
+
+ buf = hid_alloc_report_buf(r, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ /* The report ID is always 0 */
+ memcpy(buf + 1, cmd, size);
+
+ /*
+ * Sometimes the wireless controller fails with EPIPE
+ * when sending a feature report.
+ * Doing a HID_REQ_GET_REPORT and waiting for a while
+ * seems to fix that.
+ */
+ do {
+ ret = hid_hw_raw_request(steam->hdev, 0,
+ buf, size + 1,
+ HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+ if (ret != -EPIPE)
+ break;
+ steam_recv_report(steam, NULL, 0);
+ msleep(50);
+ } while (--retries);
+
+ kfree(buf);
+ if (ret < 0)
+ hid_err(steam->hdev, "%s: error %d (%*ph)\n", __func__,
+ ret, size, cmd);
+ return ret;
+}
+
+static int steam_get_serial(struct steam_device *steam)
+{
+ /*
+ * Send: 0xae 0x15 0x01
+ * Recv: 0xae 0x15 0x01 serialnumber (10 chars)
+ */
+ int ret;
+ u8 cmd[] = {0xae, 0x15, 0x01};
+ u8 reply[3 + STEAM_SERIAL_LEN + 1];
+
+ ret = steam_send_report(steam, cmd, sizeof(cmd));
+ if (ret < 0)
+ return ret;
+ ret = steam_recv_report(steam, reply, sizeof(reply));
+ if (ret < 0)
+ return ret;
+ reply[3 + STEAM_SERIAL_LEN] = 0;
+ strlcpy(steam->serial_no, reply + 3, sizeof(steam->serial_no));
+ return 0;
+}
+
static int steam_input_open(struct input_dev *dev)
{
struct steam_device *steam = input_get_drvdata(dev);
@@ -71,7 +167,12 @@ static int steam_register(struct steam_device *steam)
return 0;
}

- hid_info(hdev, "Steam Controller connected");
+ ret = steam_get_serial(steam);
+ if (ret)
+ return ret;
+
+ hid_info(hdev, "Steam Controller '%s' connected",
+ steam->serial_no);

input = input_allocate_device();
if (!input)
@@ -86,7 +187,7 @@ static int steam_register(struct steam_device *steam)
"Wireless Steam Controller" :
"Steam Controller";
input->phys = hdev->phys;
- input->uniq = hdev->uniq;
+ input->uniq = steam->serial_no;
input->id.bustype = hdev->bus;
input->id.vendor = hdev->vendor;
input->id.product = hdev->product;
@@ -157,7 +258,8 @@ static void steam_unregister(struct steam_device *steam)
if (input) {
RCU_INIT_POINTER(steam->input, NULL);
synchronize_rcu();
- hid_info(steam->hdev, "Steam Controller disconnected");
+ hid_info(steam->hdev, "Steam Controller '%s' disconnected",
+ steam->serial_no);
input_unregister_device(input);
}
}
--
2.16.2
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