0019-CHROMIUM-Input-atmel_mxt_ts-add-deltas-and-refs-debu.patch

From 37068d2a8e22a350831a7419ae534dc24feabce3 Mon Sep 17 00:00:00 2001
From: Daniel Kurtz <djkurtz@chromium.org>
Date: Mon, 17 Dec 2012 17:32:59 +0800
Subject: [PATCH 19/57] CHROMIUM: Input: atmel_mxt_ts - add deltas and refs
 debugfs entries

Reading these two debugfs entries returns a binary blob containing the
contents of all pages of the T37 object when the DELTAS and REFERENCES
commands are requested, respectively.
The values are written to the file as they are arranged in the device's
T37 object,  that is, as a 2D array with matrix_ysize columns and
matrix_xsize rows of 2-byte (little endian) values.

It is left to userspace to parse the 2-byte values.
 * Deltas are signed 2's complement 2-byte little-endian values.
     s32 delta = (b[0] + (b[1] << 8));

 * Refs are signed 'offset binary' 2-byte little-endian values,
   with offset 16384 (0x4000):
    s32 ref = (b[0] + (b[1] << 8)) - 16384;

Userspace should use the 'matrix_size' sysfs entry to determine the
dimensions of the returned arrays.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>

BUG=chromium-os:29899
TEST=hexdump -e '52/2 "%6d" "\n"' /sys/kernel/debug/atmel_mxt_ts/<dev>/deltas
 => dumps 'delta' values in a 52-column wide grid
TEST=hexdump -e '12/2 "%6d" "\n"' /sys/kernel/debug/atmel_mxt_ts/<dev>/deltas
 => dumps the 'ref' values in a 12-column wide grid

Change-Id: I9deb64074dd9947739961aa4323573f4544e9dc1
Reviewed-on: https://gerrit.chromium.org/gerrit/21052
Commit-Ready: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Daniel Kurtz <djkurtz@chromium.org>

v3.7 rebase:
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 241 ++++++++++++++++++++++++++++++-
 1 file changed, 240 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 311959d..9a8cfd2 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -22,6 +22,7 @@
 #include <linux/input/mt.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 /* Version */
 #define MXT_VER_20		20
@@ -90,6 +91,13 @@
 #define MXT_COMMAND_REPORTALL	3
 #define MXT_COMMAND_DIAGNOSTIC	5
 
+#define MXT_T6_CMD_PAGE_UP		0x01
+#define MXT_T6_CMD_PAGE_DOWN		0x02
+#define MXT_T6_CMD_DELTAS		0x10
+#define MXT_T6_CMD_REFS			0x11
+#define MXT_T6_CMD_DEVICE_ID		0x80
+#define MXT_T6_CMD_TOUCH_THRESH		0xF4
+
 /* MXT_GEN_POWER_T7 field */
 #define MXT_POWER_IDLEACQINT	0
 #define MXT_POWER_ACTVACQINT	1
@@ -267,6 +275,13 @@ struct mxt_data {
 
 	/* per-instance debugfs root */
 	struct dentry *dentry_dev;
+	struct dentry *dentry_deltas;
+	struct dentry *dentry_refs;
+
+	/* Protect access to the T37 object buffer, used by debugfs */
+	struct mutex T37_buf_mutex;
+	u8 *T37_buf;
+	size_t T37_buf_size;
 };
 
 /* global root node of the atmel_mxt_ts debugfs directory. */
@@ -1138,6 +1153,133 @@ static void mxt_calc_resolution(struct mxt_data *data)
 	}
 }
 
+/*
+ * Helper function for performing a T6 diagnostic command
+ */
+static int mxt_T6_diag_cmd(struct mxt_data *data, struct mxt_object *T6,
+			   u8 cmd)
+{
+	int ret;
+	u16 addr = T6->start_address + MXT_COMMAND_DIAGNOSTIC;
+
+	ret = mxt_write_reg(data->client, addr, cmd);
+	if (ret)
+		return ret;
+
+	/*
+	 * Poll T6.diag until it returns 0x00, which indicates command has
+	 * completed.
+	 */
+	while (cmd != 0) {
+		ret = __mxt_read_reg(data->client, addr, 1, &cmd);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/*
+ * SysFS Helper function for reading DELTAS and REFERENCE values for T37 object
+ *
+ * For both modes, a T37_buf is allocated to stores matrix_xsize * matrix_ysize
+ * 2-byte (little-endian) values, which are returned to userspace unmodified.
+ *
+ * It is left to userspace to parse the 2-byte values.
+ * - deltas are signed 2's complement 2-byte little-endian values.
+ *     s32 delta = (b[0] + (b[1] << 8));
+ * - refs are signed 'offset binary' 2-byte little-endian values, with offset
+ *   value 0x4000:
+ *     s32 ref = (b[0] + (b[1] << 8)) - 0x4000;
+ */
+static ssize_t mxt_T37_fetch(struct mxt_data *data, u8 mode)
+{
+	struct mxt_object *T6, *T37;
+	u8 *obuf;
+	ssize_t ret = 0;
+	size_t i;
+	size_t T37_buf_size, num_pages;
+	size_t pos;
+
+	if (!data || !data->object_table)
+		return -ENODEV;
+
+	T6 = mxt_get_object(data, MXT_GEN_COMMAND_T6);
+	T37 = mxt_get_object(data, MXT_DEBUG_DIAGNOSTIC_T37);
+	if (!T6 || mxt_obj_size(T6) < 6 || !T37 || mxt_obj_size(T37) < 3) {
+		dev_err(&data->client->dev, "Invalid T6 or T37 object\n");
+		return -ENODEV;
+	}
+
+	/* Something has gone wrong if T37_buf is already allocated */
+	if (data->T37_buf)
+		return -EINVAL;
+
+	T37_buf_size = data->info.matrix_xsize * data->info.matrix_ysize *
+		       sizeof(__le16);
+	data->T37_buf_size = T37_buf_size;
+	data->T37_buf = kmalloc(data->T37_buf_size, GFP_KERNEL);
+	if (!data->T37_buf)
+		return -ENOMEM;
+
+	/* Temporary buffer used to fetch one T37 page */
+	obuf = kmalloc(mxt_obj_size(T37), GFP_KERNEL);
+	if (!obuf)
+		return -ENOMEM;
+
+	disable_irq(data->irq);
+	num_pages = DIV_ROUND_UP(T37_buf_size, mxt_obj_size(T37) - 2);
+	pos = 0;
+	for (i = 0; i < num_pages; i++) {
+		u8 cmd;
+		size_t chunk_len;
+
+		/* For first page, send mode as cmd, otherwise PageUp */
+		cmd = (i == 0) ? mode : MXT_T6_CMD_PAGE_UP;
+		ret = mxt_T6_diag_cmd(data, T6, cmd);
+		if (ret)
+			goto err_free_T37_buf;
+
+		ret = __mxt_read_reg(data->client, T37->start_address,
+				mxt_obj_size(T37), obuf);
+		if (ret)
+			goto err_free_T37_buf;
+
+		/* Verify first two bytes are current mode and page # */
+		if (obuf[0] != mode) {
+			dev_err(&data->client->dev,
+				"Unexpected mode (%u != %u)\n", obuf[0], mode);
+			ret = -EIO;
+			goto err_free_T37_buf;
+		}
+
+		if (obuf[1] != i) {
+			dev_err(&data->client->dev,
+				"Unexpected page (%u != %zu)\n", obuf[1], i);
+			ret = -EIO;
+			goto err_free_T37_buf;
+		}
+
+		/*
+		 * Copy the data portion of the page, or however many bytes are
+		 * left, whichever is less.
+		 */
+		chunk_len = min(mxt_obj_size(T37) - 2, T37_buf_size - pos);
+		memcpy(&data->T37_buf[pos], &obuf[2], chunk_len);
+		pos += chunk_len;
+	}
+
+	goto out;
+
+err_free_T37_buf:
+	kfree(data->T37_buf);
+	data->T37_buf = NULL;
+	data->T37_buf_size = 0;
+out:
+	kfree(obuf);
+	enable_irq(data->irq);
+	return ret ?: 0;
+}
+
 static ssize_t mxt_calibrate_store(struct device *dev,
 				   struct device_attribute *attr,
 				   const char *buf, size_t count)
@@ -1374,6 +1516,92 @@ static const struct attribute_group mxt_attr_group = {
  * debugfs interface
  **************************************************************
 */
+static int mxt_debugfs_T37_open(struct inode *inode, struct file *file)
+{
+	struct mxt_data *mxt = inode->i_private;
+	int ret;
+	u8 cmd;
+
+	if (file->f_dentry == mxt->dentry_deltas)
+		cmd = MXT_T6_CMD_DELTAS;
+	else if (file->f_dentry == mxt->dentry_refs)
+		cmd = MXT_T6_CMD_REFS;
+	else
+		return -EINVAL;
+
+	/* Only allow one T37 debugfs file to be opened at a time */
+	ret = mutex_lock_interruptible(&mxt->T37_buf_mutex);
+	if (ret)
+		return ret;
+
+	if (!i2c_use_client(mxt->client)) {
+		ret = -ENODEV;
+		goto err_unlock;
+	}
+
+	/* Fetch all T37 pages into mxt->T37_buf */
+	ret = mxt_T37_fetch(mxt, cmd);
+	if (ret)
+		goto err_release;
+
+	file->private_data = mxt;
+
+	return 0;
+
+err_release:
+	i2c_release_client(mxt->client);
+err_unlock:
+	mutex_unlock(&mxt->T37_buf_mutex);
+	return ret;
+}
+
+static int mxt_debugfs_T37_release(struct inode *inode, struct file *file)
+{
+	struct mxt_data *mxt = file->private_data;
+
+	file->private_data = NULL;
+
+	kfree(mxt->T37_buf);
+	mxt->T37_buf = NULL;
+	mxt->T37_buf_size = 0;
+
+	i2c_release_client(mxt->client);
+	mutex_unlock(&mxt->T37_buf_mutex);
+
+	return 0;
+}
+
+
+/* Return some bytes from the buffered T37 object, starting from *ppos */
+static ssize_t mxt_debugfs_T37_read(struct file *file, char __user *buffer,
+				    size_t count, loff_t *ppos)
+{
+	struct mxt_data *mxt = file->private_data;
+
+	if (!mxt->T37_buf)
+		return -ENODEV;
+
+	if (*ppos >= mxt->T37_buf_size)
+		return 0;
+
+	if (count + *ppos > mxt->T37_buf_size)
+		count = mxt->T37_buf_size - *ppos;
+
+	if (copy_to_user(buffer, &mxt->T37_buf[*ppos], count))
+		return -EFAULT;
+
+	*ppos += count;
+
+	return count;
+}
+
+static const struct file_operations mxt_debugfs_T37_fops = {
+	.owner = THIS_MODULE,
+	.open = mxt_debugfs_T37_open,
+	.release = mxt_debugfs_T37_release,
+	.read = mxt_debugfs_T37_read
+};
+
 static int mxt_debugfs_init(struct mxt_data *mxt)
 {
 	struct device *dev = &mxt->client->dev;
@@ -1387,6 +1615,14 @@ static int mxt_debugfs_init(struct mxt_data *mxt)
 	if (!mxt->dentry_dev)
 		return -ENODEV;
 
+	mutex_init(&mxt->T37_buf_mutex);
+
+	mxt->dentry_deltas = debugfs_create_file("deltas", S_IRUSR,
+						 mxt->dentry_dev, mxt,
+						 &mxt_debugfs_T37_fops);
+	mxt->dentry_refs = debugfs_create_file("refs", S_IRUSR,
+					       mxt->dentry_dev, mxt,
+					       &mxt_debugfs_T37_fops);
 	return 0;
 }
 
@@ -1561,8 +1797,11 @@ static int mxt_remove(struct i2c_client *client)
 {
 	struct mxt_data *data = i2c_get_clientdata(client);
 
-	if (data->dentry_dev)
+	if (data->dentry_dev) {
 		debugfs_remove_recursive(data->dentry_dev);
+		mutex_destroy(&data->T37_buf_mutex);
+		kfree(data->T37_buf);
+	}
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 	free_irq(data->irq, data);
 	if (data->input_dev)
-- 
1.8.2.1