Re: [RFC PATCH 1/11] input: RMI4 public header file and documentation.

On Wed, Dec 21, 2011 at 06:09:52PM -0800, Christopher Heiny wrote:

+
+/* Helper fn to convert a byte array representing a short in the RMI
+ * endian-ness to a short in the native processor's specific endianness.
+ * We don't use ntohs/htons here because, well, we're not dealing with
+ * a pair of shorts. And casting dest to short* wouldn't work, because
+ * that would imply knowing the byte order of short in the first place.
+ */
+static inline void batohs(unsigned short *dest, unsigned char *src)
+{
+	*dest = src[1] * 0x100 + src[0];
+}
+
+/* Helper function to convert a short (in host processor endianess) to
+ * a byte array in the RMI endianess for shorts.  See above comment for
+ * why we dont us htons or something like that.
+ */
+static inline void hstoba(unsigned char *dest, unsigned short src)
+{
+	dest[0] = src % 0x100;
+	dest[1] = src / 0x100;
+}

We have nice set of be/le16_to_cpu and cpu_to_be/le16 helpers that do
just that and in much more efficient way.

+
+/* Utility routine to handle writes to read-only attributes.  Hopefully
+ * this will never happen, but if the user does something stupid, we don't
+ * want to accept it quietly (which is what can happen if you just put NULL
+ * for the attribute's store function).
+ */
+static inline ssize_t rmi_store_error(struct device *dev,
+			struct device_attribute *attr,
+			const char *buf, size_t count)
+{
+	dev_warn(dev,
+		 "RMI4 WARNING: Attempt to write %d characters to read-only "
+		 "attribute %s.", count, attr->attr.name);
+	return -EPERM;
+}
+
+/* Utility routine to handle reads of write-only attributes.  Hopefully
+ * this will never happen, but if the user does something stupid, we don't
+ * want to accept it quietly (which is what can happen if you just put NULL
+ * for the attribute's show function).
+ */
+static inline ssize_t rmi_show_error(struct device *dev,
+		       struct device_attribute *attr,
+		       char *buf)
+{
+	dev_warn(dev,
+		 "RMI4 WARNING: Attempt to read from write-only attribute %s.",
+		 attr->attr.name);
+	return -EPERM;
+}

Although these methods are not needed, a general comment nonetheless: do
not put in header files and mark inline functions which address is taken
and used elsewhere.

Thanks.

-- 
Dmitry