From 3c3fcfdd4889dfeb1c80ae8cd94a622c6342b06a Mon Sep 17 00:00:00 2001
From: Nick Dyer <nick.dyer@itdev.co.uk>
Date: Tue, 23 Aug 2011 16:40:30 +0100
Subject: [PATCH] Input: atmel_mxt_ts - implement debug output for messages

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 | 44 ++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 80fd5b4a90f7f9..250df52822ba0b 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -283,6 +283,7 @@ struct mxt_data {
 	u8 t100_aux_ampl;
 	u8 t100_aux_area;
 	u8 t100_aux_vect;
+	bool debug_enabled;
 	u8 max_reportid;
 	u32 config_crc;
 	u32 info_crc;
@@ -391,8 +392,8 @@ static bool mxt_object_readable(unsigned int type)
 
 static void mxt_dump_message(struct mxt_data *data, u8 *message)
 {
-	dev_dbg(&data->client->dev, "message: %*ph\n",
-		data->T5_msg_size, message);
+	dev_dbg(&data->client->dev, "MXT MSG: %*ph\n",
+		       data->T5_msg_size, message);
 }
 
 static int mxt_wait_for_completion(struct mxt_data *data,
@@ -1145,6 +1146,7 @@ static void mxt_proc_t93_messages(struct mxt_data *data, u8 *msg)
 static int mxt_proc_message(struct mxt_data *data, u8 *message)
 {
 	u8 report_id = message[0];
+	bool dump = data->debug_enabled;
 
 	if (report_id == MXT_RPTID_NOMSG)
 		return 0;
@@ -1179,9 +1181,12 @@ static int mxt_proc_message(struct mxt_data *data, u8 *message)
 	} else if (report_id == data->T93_reportid) {
 		mxt_proc_t93_messages(data, message);
 	} else {
-		mxt_dump_message(data, message);
+		dump = true;
 	}
 
+	if (dump)
+		mxt_dump_message(data, message);
+
 	return 1;
 }
 
@@ -2989,6 +2994,36 @@ static ssize_t mxt_update_cfg_store(struct device *dev,
 	return ret;
 }
 
+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);
+	u8 i;
+	ssize_t ret;
+
+	if (kstrtou8(buf, 0, &i) == 0 && i < 2) {
+		data->debug_enabled = (i == 1);
+
+		dev_dbg(dev, "%s\n", i ? "debug enabled" : "debug disabled");
+		ret = count;
+	} else {
+		dev_dbg(dev, "debug_enabled write error\n");
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
 static DEVICE_ATTR(update_fw, S_IWUSR, NULL, mxt_update_fw_store);
 
 static struct attribute *mxt_fw_attrs[] = {
@@ -3005,6 +3040,8 @@ 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_cfg, S_IWUSR, NULL, mxt_update_cfg_store);
 static DEVICE_ATTR(config_crc, S_IRUGO, mxt_config_crc_show, NULL);
+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,
@@ -3012,6 +3049,7 @@ static struct attribute *mxt_attrs[] = {
 	&dev_attr_object.attr,
 	&dev_attr_update_cfg.attr,
 	&dev_attr_config_crc.attr,
+	&dev_attr_debug_enable.attr,
 	NULL
 };