Input: atmel_mxt_ts - define helper functions for size and instances

These two object table entry fields are reported 1 less than their value.
When used, however, we always want the actual size and instances.

To keep the object size and instances 1-byte fields, and thus preserve
the object-table struct's 6-byte packed alignment, add some convenient
accessor functions that do the +1 every time these fields are accessed.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 25 insertions, 12 deletions

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 0cff8bb2ad75..40af02c26113 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -2,6 +2,8 @@
  * Atmel maXTouch Touchscreen driver
  *
  * Copyright (C) 2010 Samsung Electronics Co.Ltd
+ * Copyright (C) 2012 Google, Inc.
+ *
  * Author: Joonyoung Shim <jy0922.shim@samsung.com>
  *
  * This program is free software; you can redistribute  it and/or modify it
@@ -226,8 +228,8 @@ struct mxt_info {
 struct mxt_object {
         u8 type;
         u16 start_address;
-        u8 size;                /* Size of each instance - 1 */
-        u8 instances;           /* Number of instances - 1 */
+        u8 size_minus_one;
+        u8 instances_minus_one;
         u8 num_report_ids;
 } __packed;
 
@@ -256,6 +258,16 @@ struct mxt_data {
         u8 T19_reportid;
 };
 
+static size_t mxt_obj_size(const struct mxt_object *obj)
+{
+        return obj->size_minus_one + 1;
+}
+
+static size_t mxt_obj_instances(const struct mxt_object *obj)
+{
+        return obj->instances_minus_one + 1;
+}
+
 static bool mxt_object_readable(unsigned int type)
 {
         switch (type) {
@@ -498,7 +510,7 @@ static int mxt_write_object(struct mxt_data *data,
         u16 reg;
 
         object = mxt_get_object(data, type);
-        if (!object || offset >= object->size + 1)
+        if (!object || offset >= mxt_obj_size(object))
                 return -EINVAL;
 
         reg = object->start_address;
@@ -640,7 +652,7 @@ static int mxt_check_reg_init(struct mxt_data *data)
                 if (!mxt_object_writable(object->type))
                         continue;
 
-                size = (object->size + 1) * (object->instances + 1);
+                size = mxt_obj_size(object) * mxt_obj_instances(object);
                 if (index + size > pdata->config_length) {
                         dev_err(dev, "Not enough config data!\n");
                         return -EINVAL;
@@ -717,7 +729,7 @@ static int mxt_get_object_table(struct mxt_data *data)
                 if (object->num_report_ids) {
                         min_id = reportid;
                         reportid += object->num_report_ids *
-                                        (object->instances + 1);
+                                        mxt_obj_instances(object);
                         max_id = reportid - 1;
                 } else {
                         min_id = 0;
@@ -725,9 +737,10 @@ static int mxt_get_object_table(struct mxt_data *data)
                 }
 
                 dev_dbg(&data->client->dev,
-                        "Type %2d Start %3d Size %3d Instances %2d ReportIDs %3u : %3u\n",
-                        object->type, object->start_address, object->size + 1,
-                        object->instances + 1, min_id, max_id);
+                        "Type %2d Start %3d Size %3zd Instances %2zd ReportIDs %3u : %3u\n",
+                        object->type, object->start_address,
+                        mxt_obj_size(object), mxt_obj_instances(object),
+                        min_id, max_id);
 
                 switch (object->type) {
                 case MXT_GEN_COMMAND_T6:
@@ -864,11 +877,11 @@ static ssize_t mxt_show_instance(char *buf, int count,
 {
         int i;
 
-        if (object->instances > 0)
+        if (mxt_obj_instances(object) > 1)
                 count += scnprintf(buf + count, PAGE_SIZE - count,
                                    "Instance %u\n", instance);
 
-        for (i = 0; i < object->size + 1; i++)
+        for (i = 0; i < mxt_obj_size(object); i++)
                 count += scnprintf(buf + count, PAGE_SIZE - count,
                                 "\t[%2u]: %02x (%d)\n", i, val[i], val[i]);
         count += scnprintf(buf + count, PAGE_SIZE - count, "\n");
@@ -901,8 +914,8 @@ static ssize_t mxt_object_show(struct device *dev,
                 count += scnprintf(buf + count, PAGE_SIZE - count,
                                 "T%u:\n", object->type);
 
-                for (j = 0; j < object->instances + 1; j++) {
-                        u16 size = object->size + 1;
+                for (j = 0; j < mxt_obj_instances(object); j++) {
+                        u16 size = mxt_obj_size(object);
                         u16 addr = object->start_address + j * size;
 
                         error = __mxt_read_reg(data->client, addr, size, obuf);