ath9k: add debugfs support for hw TPC

Add tpc entry to ath9k debugfs in order to enable/disable hw TPC
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/debug.c

@@ -1115,6 +1115,75 @@ static const struct file_operations fops_ackto = {
 };
 #endif
 
+static ssize_t read_file_tpc(struct file *file, char __user *user_buf,
+			     size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	struct ath_hw *ah = sc->sc_ah;
+	unsigned int len = 0, size = 32;
+	ssize_t retval;
+	char *buf;
+
+	buf = kzalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len += scnprintf(buf + len, size - len, "%s\n",
+			 ah->tpc_enabled ? "ENABLED" : "DISABLED");
+
+	if (len > size)
+		len = size;
+
+	retval = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+	kfree(buf);
+
+	return retval;
+}
+
+static ssize_t write_file_tpc(struct file *file, const char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct ath_softc *sc = file->private_data;
+	struct ath_hw *ah = sc->sc_ah;
+	unsigned long val;
+	char buf[32];
+	ssize_t len;
+	bool tpc_enabled;
+
+	if (!AR_SREV_9300_20_OR_LATER(ah)) {
+		/* ar9002 does not support TPC for the moment */
+		return -EOPNOTSUPP;
+	}
+
+	len = min(count, sizeof(buf) - 1);
+	if (copy_from_user(buf, user_buf, len))
+		return -EFAULT;
+
+	buf[len] = '\0';
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val < 0 || val > 1)
+		return -EINVAL;
+
+	tpc_enabled = !!val;
+
+	if (tpc_enabled != ah->tpc_enabled) {
+		ah->tpc_enabled = tpc_enabled;
+		ath9k_hw_set_txpowerlimit(ah, sc->cur_chan->txpower, false);
+	}
+
+	return count;
+}
+
+static const struct file_operations fops_tpc = {
+	.read = read_file_tpc,
+	.write = write_file_tpc,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
 /* Ethtool support for get-stats */
 
 #define AMKSTR(nm) #nm "_BE", #nm "_BK", #nm "_VI", #nm "_VO"
@@ -1324,6 +1393,8 @@ int ath9k_init_debug(struct ath_hw *ah)
 	debugfs_create_file("ack_to", S_IRUSR | S_IWUSR, sc->debug.debugfs_phy,
 			    sc, &fops_ackto);
 #endif
+	debugfs_create_file("tpc", S_IRUSR | S_IWUSR,
+			    sc->debug.debugfs_phy, sc, &fops_tpc);
 
 	return 0;
 }