hwmon: (corsair-cpro) Add firmware and bootloader information

Add support for reporting firmware and bootloader version using debugfs.
Update documentation accordingly.
Signed-off-by: Marius Zachmann <mail@mariuszachmann.de>
Link: https://lore.kernel.org/r/20240513194734.43040-2-mail@mariuszachmann.deSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/corsair-cpro.rst

@@ -39,3 +39,11 @@ fan[1-6]_target		Sets fan speed target rpm.
 pwm[1-6]		Sets the fan speed. Values from 0-255. Can only be read if pwm
 			was set directly.
 ======================= =====================================================================
+
+Debugfs entries
+---------------
+
+======================= ===================
+firmware_version	Firmware version
+bootloader_version	Bootloader version
+======================= ===================

drivers/hwmon/corsair-cpro.c

@@ -10,11 +10,13 @@
 
 #include <linux/bitops.h>
 #include <linux/completion.h>
+#include <linux/debugfs.h>
 #include <linux/hid.h>
 #include <linux/hwmon.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
@@ -28,6 +30,8 @@
 #define LABEL_LENGTH		11
 #define REQ_TIMEOUT		300
 
+#define CTL_GET_FW_VER		0x02	/* returns the firmware version in bytes 1-3 */
+#define CTL_GET_BL_VER		0x06	/* returns the bootloader version in bytes 1-2 */
 #define CTL_GET_TMP_CNCT	0x10	/*
 					 * returns in bytes 1-4 for each temp sensor:
 					 * 0 not connected
@@ -78,6 +82,7 @@
 struct ccp_device {
 	struct hid_device *hdev;
 	struct device *hwmon_dev;
+	struct dentry *debugfs;
 	/* For reinitializing the completion below */
 	spinlock_t wait_input_report_lock;
 	struct completion wait_input_report;
@@ -88,6 +93,8 @@ struct ccp_device {
 	DECLARE_BITMAP(temp_cnct, NUM_TEMP_SENSORS);
 	DECLARE_BITMAP(fan_cnct, NUM_FANS);
 	char fan_label[6][LABEL_LENGTH];
+	u8 firmware_ver[3];
+	u8 bootloader_ver[2];
 };
 
 /* converts response error in buffer to errno */
@@ -496,6 +503,83 @@ static int get_temp_cnct(struct ccp_device *ccp)
 	return 0;
 }
 
+/* read firmware version */
+static int get_fw_version(struct ccp_device *ccp)
+{
+	int ret;
+
+	ret = send_usb_cmd(ccp, CTL_GET_FW_VER, 0, 0, 0);
+	if (ret) {
+		hid_notice(ccp->hdev, "Failed to read firmware version.\n");
+		return ret;
+	}
+	ccp->firmware_ver[0] = ccp->buffer[1];
+	ccp->firmware_ver[1] = ccp->buffer[2];
+	ccp->firmware_ver[2] = ccp->buffer[3];
+
+	return 0;
+}
+
+/* read bootloader version */
+static int get_bl_version(struct ccp_device *ccp)
+{
+	int ret;
+
+	ret = send_usb_cmd(ccp, CTL_GET_BL_VER, 0, 0, 0);
+	if (ret) {
+		hid_notice(ccp->hdev, "Failed to read bootloader version.\n");
+		return ret;
+	}
+	ccp->bootloader_ver[0] = ccp->buffer[1];
+	ccp->bootloader_ver[1] = ccp->buffer[2];
+
+	return 0;
+}
+
+static int firmware_show(struct seq_file *seqf, void *unused)
+{
+	struct ccp_device *ccp = seqf->private;
+
+	seq_printf(seqf, "%d.%d.%d\n",
+		   ccp->firmware_ver[0],
+		   ccp->firmware_ver[1],
+		   ccp->firmware_ver[2]);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(firmware);
+
+static int bootloader_show(struct seq_file *seqf, void *unused)
+{
+	struct ccp_device *ccp = seqf->private;
+
+	seq_printf(seqf, "%d.%d\n",
+		   ccp->bootloader_ver[0],
+		   ccp->bootloader_ver[1]);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(bootloader);
+
+static void ccp_debugfs_init(struct ccp_device *ccp)
+{
+	char name[32];
+	int ret;
+
+	scnprintf(name, sizeof(name), "corsaircpro-%s", dev_name(&ccp->hdev->dev));
+	ccp->debugfs = debugfs_create_dir(name, NULL);
+
+	ret = get_fw_version(ccp);
+	if (!ret)
+		debugfs_create_file("firmware_version", 0444,
+				    ccp->debugfs, ccp, &firmware_fops);
+
+	ret = get_bl_version(ccp);
+	if (!ret)
+		debugfs_create_file("bootloader_version", 0444,
+				    ccp->debugfs, ccp, &bootloader_fops);
+}
+
 static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	struct ccp_device *ccp;
@@ -542,6 +626,9 @@ static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	ret = get_fan_cnct(ccp);
 	if (ret)
 		goto out_hw_close;
+
+	ccp_debugfs_init(ccp);
+
 	ccp->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "corsaircpro",
 							 ccp, &ccp_chip_info, NULL);
 	if (IS_ERR(ccp->hwmon_dev)) {
@@ -562,6 +649,7 @@ static void ccp_remove(struct hid_device *hdev)
 {
 	struct ccp_device *ccp = hid_get_drvdata(hdev);
 
+	debugfs_remove_recursive(ccp->debugfs);
 	hwmon_device_unregister(ccp->hwmon_dev);
 	hid_hw_close(hdev);
 	hid_hw_stop(hdev);