[PATCH 11/53] Input: atmel_mxt_ts - Implement debug output for messages

[Nick Dyer <nick.dyer@itdev.co.uk>]

Add a debug switch which causes all messages from the touch controller to be
dumped to the dmesg log with a set prefix "MXT MSG:". This is used by Atmel
user-space utilities to debug touch operation. Enabling this output does
impact touch performance.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
---
 drivers/input/touchscreen/atmel_mxt_ts.c |   52 ++++++++++++++++++++++++++----
 1 file changed, 45 insertions(+), 7 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index b4bc16f..08cd7ff 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -83,6 +83,9 @@
 #define MXT_SPT_MESSAGECOUNT_T44	44
 #define MXT_SPT_CTECONFIG_T46		46
 
+/* MXT_GEN_MESSAGE_T5 object */
+#define MXT_RPTID_NOMSG		0xff
+
 /* MXT_GEN_COMMAND_T6 field */
 #define MXT_COMMAND_RESET	0
 #define MXT_COMMAND_BACKUPNV	1
@@ -264,6 +267,7 @@ struct mxt_data {
 	bool in_bootloader;
 	u16 mem_size;
 	struct bin_attribute mem_access_attr;
+	bool debug_enabled;
 
 	/* Cached parameters from object table */
 	u8 T6_reportid;
@@ -356,11 +360,10 @@ static bool mxt_object_writable(unsigned int type)
 	}
 }
 
-static void mxt_dump_message(struct device *dev,
-			     struct mxt_message *message)
+static void mxt_dump_message(struct device *dev, struct mxt_message *message)
 {
-	dev_dbg(dev, "reportid: %u\tmessage: %*ph\n",
-		message->reportid, 7, message->message);
+	dev_dbg(dev, "MXT MSG: %*ph\n",
+		       sizeof(struct mxt_message), message);
 }
 
 static int mxt_wait_for_completion(struct mxt_data *data,
@@ -669,6 +672,7 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
 	struct device *dev = &data->client->dev;
 	u8 reportid;
 	bool update_input = false;
+	bool dump;
 
 	do {
 		if (mxt_read_message(data, &message)) {
@@ -677,6 +681,7 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
 		}
 
 		reportid = message.reportid;
+		dump = data->debug_enabled;
 
 		if (reportid == data->T6_reportid) {
 			u8 status = payload[0];
@@ -694,9 +699,12 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
 			mxt_input_button(data, &message);
 			update_input = true;
 		} else {
-			mxt_dump_message(dev, &message);
+			dump = true;
 		}
-	} while (reportid != 0xff);
+
+		if (dump)
+			mxt_dump_message(dev, &message);
+	} while (reportid != MXT_RPTID_NOMSG);
 
 	if (data->enable_reporting && update_input) {
 		input_mt_report_pointer_emulation(data->input_dev, false);
@@ -823,7 +831,7 @@ static int mxt_make_highchg(struct mxt_data *data)
 		error = mxt_read_message(data, &message);
 		if (error)
 			return error;
-	} while (message.reportid != 0xff && --count);
+	} while (message.reportid != MXT_RPTID_NOMSG && --count);
 
 	if (!count) {
 		dev_err(dev, "CHG pin isn't cleared\n");
@@ -1210,6 +1218,33 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 	return count;
 }
 
+static ssize_t mxt_debug_enable_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct mxt_data *data = dev_get_drvdata(dev);
+	char c;
+
+	c = data->debug_enabled ? '1' : '0';
+	return scnprintf(buf, PAGE_SIZE, "%c\n", c);
+}
+
+static ssize_t mxt_debug_enable_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct mxt_data *data = dev_get_drvdata(dev);
+	int i;
+
+	if (sscanf(buf, "%u", &i) == 1 && i < 2) {
+		data->debug_enabled = (i == 1);
+
+		dev_dbg(dev, "%s\n", i ? "debug enabled" : "debug disabled");
+		return count;
+	} else {
+		dev_dbg(dev, "debug_enabled write error\n");
+		return -EINVAL;
+	}
+}
+
 static int mxt_check_mem_access_params(struct mxt_data *data, loff_t off,
 				       size_t *count)
 {
@@ -1264,12 +1299,15 @@ static DEVICE_ATTR(fw_version, S_IRUGO, mxt_fw_version_show, NULL);
 static DEVICE_ATTR(hw_version, S_IRUGO, mxt_hw_version_show, NULL);
 static DEVICE_ATTR(object, S_IRUGO, mxt_object_show, NULL);
 static DEVICE_ATTR(update_fw, S_IWUSR, NULL, mxt_update_fw_store);
+static DEVICE_ATTR(debug_enable, S_IWUSR | S_IRUSR, mxt_debug_enable_show,
+		   mxt_debug_enable_store);
 
 static struct attribute *mxt_attrs[] = {
 	&dev_attr_fw_version.attr,
 	&dev_attr_hw_version.attr,
 	&dev_attr_object.attr,
 	&dev_attr_update_fw.attr,
+	&dev_attr_debug_enable.attr,
 	NULL
 };
 
-- 
1.7.10.4