[01/25] HID: break out hid_extract_field

Commit Message

Benjamin Tissoires Jan. 25, 2013, 1:22 p.m. UTC

Breaking out this function allows third parties hid drivers to retrieve
the data fields of a hid report in the raw_event callback.

No functional changes, only exports the function.

Signed-off-by: Benjamin Tissoires <[e-mail]>
---
 drivers/hid/hid-core.c | 60 ++++++++++++++++++++++++++++++++++----------------
 include/linux/hid.h    |  1 +
 2 files changed, 42 insertions(+), 19 deletions(-)

Comments

Henrik Rydberg Jan. 28, 2013, 3:04 p.m. UTC | #1

Hi Benjamin,

> Breaking out this function allows third parties hid drivers to retrieve
> the data fields of a hid report in the raw_event callback.
> 
> No functional changes, only exports the function.
> 
> Signed-off-by: Benjamin Tissoires <[e-mail]>
> ---
>  drivers/hid/hid-core.c | 60 ++++++++++++++++++++++++++++++++++----------------
>  include/linux/hid.h    |  1 +
>  2 files changed, 42 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 5ae2cb1..ea478f5 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -962,6 +962,45 @@ static void implement(const struct hid_device *hid, __u8 *report,
>  }
>  
>  /*
> + * Extract and allocate a data field from a little endian report (bit array).
> + */
> +
> +s32 *hid_extract_field(const struct hid_device *hid, struct hid_field *field,
> +		       __u8 *data)
> +{
> +	unsigned n;
> +	unsigned count = field->report_count;
> +	unsigned offset = field->report_offset;
> +	unsigned size = field->report_size;
> +	__s32 min = field->logical_minimum;
> +	__s32 max = field->logical_maximum;
> +	__s32 *value;
> +
> +	value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC);
> +	if (!value)
> +		return value;
> +
> +	for (n = 0; n < count; n++) {
> +
> +		value[n] = min < 0 ?
> +			snto32(extract(hid, data, offset + n * size, size),
> +			       size) :
> +			extract(hid, data, offset + n * size, size);
> +
> +		/* Ignore report if ErrorRollOver */
> +		if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
> +		    value[n] >= min && value[n] <= max &&
> +		    field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) {
> +			kfree(value);
> +			return NULL;
> +		}
> +	}
> +
> +	return value;
> +}
> +EXPORT_SYMBOL_GPL(hid_extract_field);
> +

I would rather see the extensive use of malloc go away than extend its
usage to drivers.

Thanks,
Henrik
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 5ae2cb1..ea478f5 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -962,6 +962,45 @@  static void implement(const struct hid_device *hid, __u8 *report,
 }
 
 /*
+ * Extract and allocate a data field from a little endian report (bit array).
+ */
+
+s32 *hid_extract_field(const struct hid_device *hid, struct hid_field *field,
+		       __u8 *data)
+{
+	unsigned n;
+	unsigned count = field->report_count;
+	unsigned offset = field->report_offset;
+	unsigned size = field->report_size;
+	__s32 min = field->logical_minimum;
+	__s32 max = field->logical_maximum;
+	__s32 *value;
+
+	value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC);
+	if (!value)
+		return value;
+
+	for (n = 0; n < count; n++) {
+
+		value[n] = min < 0 ?
+			snto32(extract(hid, data, offset + n * size, size),
+			       size) :
+			extract(hid, data, offset + n * size, size);
+
+		/* Ignore report if ErrorRollOver */
+		if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
+		    value[n] >= min && value[n] <= max &&
+		    field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) {
+			kfree(value);
+			return NULL;
+		}
+	}
+
+	return value;
+}
+EXPORT_SYMBOL_GPL(hid_extract_field);
+
+/*
  * Search an array for a value.
  */
 
@@ -1059,32 +1098,15 @@  static void hid_input_field(struct hid_device *hid, struct hid_field *field,
 {
 	unsigned n;
 	unsigned count = field->report_count;
-	unsigned offset = field->report_offset;
-	unsigned size = field->report_size;
 	__s32 min = field->logical_minimum;
 	__s32 max = field->logical_maximum;
-	__s32 *value;
+	__s32 *value = hid_extract_field(hid, field, data);
 
-	value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC);
 	if (!value)
 		return;
 
 	for (n = 0; n < count; n++) {
 
-		value[n] = min < 0 ?
-			snto32(extract(hid, data, offset + n * size, size),
-			       size) :
-			extract(hid, data, offset + n * size, size);
-
-		/* Ignore report if ErrorRollOver */
-		if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
-		    value[n] >= min && value[n] <= max &&
-		    field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
-			goto exit;
-	}
-
-	for (n = 0; n < count; n++) {
-
 		if (HID_MAIN_ITEM_VARIABLE & field->flags) {
 			hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
 			continue;
@@ -1102,7 +1124,7 @@  static void hid_input_field(struct hid_device *hid, struct hid_field *field,
 	}
 
 	memcpy(field->value, value, count * sizeof(__s32));
-exit:
+
 	kfree(value);
 }
 
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 828726c..91bfee4 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -718,6 +718,7 @@  extern int hidinput_connect(struct hid_device *hid, unsigned int force);
 extern void hidinput_disconnect(struct hid_device *);
 
 int hid_set_field(struct hid_field *, unsigned, __s32);
+s32 *hid_extract_field(const struct hid_device *, struct hid_field *, __u8 *);
 int hid_input_report(struct hid_device *, int type, u8 *, int, int);
 int hidinput_find_field(struct hid_device *hid, unsigned int type, unsigned int code, struct hid_field **field);
 struct hid_field *hidinput_get_led_field(struct hid_device *hid);