Input: imx_keypad - check error returned by clk_prepare_enable()

[~andy/linux] / Documentation / CodingStyle

diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle
index 2b90d328b3ba5595c4f3a0e6bdc7c236346f550c..cb9258b8fd35b25b8ac750b18b4237204213fbd4 100644 (file)
--- a/Documentation/CodingStyle
+++ b/Documentation/CodingStyle
@@ -671,8 +671,9 @@ ones already enabled by DEBUG.
                Chapter 14: Allocating memory
 
 The kernel provides the following general purpose memory allocators:
-kmalloc(), kzalloc(), kcalloc(), vmalloc(), and vzalloc().  Please refer to
-the API documentation for further information about them.
+kmalloc(), kzalloc(), kmalloc_array(), kcalloc(), vmalloc(), and
+vzalloc().  Please refer to the API documentation for further information
+about them.
 
 The preferred form for passing a size of a struct is the following:
 
@@ -686,6 +687,17 @@ Casting the return value which is a void pointer is redundant. The conversion
 from void pointer to any other pointer type is guaranteed by the C programming
 language.
 
+The preferred form for allocating an array is the following:
+
+       p = kmalloc_array(n, sizeof(...), ...);
+
+The preferred form for allocating a zeroed array is the following:
+
+       p = kcalloc(n, sizeof(...), ...);
+
+Both forms check for overflow on the allocation size n * sizeof(...),
+and return NULL if that occurred.
+
 
                Chapter 15: The inline disease
 
@@ -793,6 +805,35 @@ own custom mode, or may have some other magic method for making indentation
 work correctly.
 
 
+               Chapter 19:  Inline assembly
+
+In architecture-specific code, you may need to use inline assembly to interface
+with CPU or platform functionality.  Don't hesitate to do so when necessary.
+However, don't use inline assembly gratuitously when C can do the job.  You can
+and should poke hardware from C when possible.
+
+Consider writing simple helper functions that wrap common bits of inline
+assembly, rather than repeatedly writing them with slight variations.  Remember
+that inline assembly can use C parameters.
+
+Large, non-trivial assembly functions should go in .S files, with corresponding
+C prototypes defined in C header files.  The C prototypes for assembly
+functions should use "asmlinkage".
+
+You may need to mark your asm statement as volatile, to prevent GCC from
+removing it if GCC doesn't notice any side effects.  You don't always need to
+do so, though, and doing so unnecessarily can limit optimization.
+
+When writing a single inline assembly statement containing multiple
+instructions, put each instruction on a separate line in a separate quoted
+string, and end each string except the last with \n\t to properly indent the
+next instruction in the assembly output:
+
+       asm ("magic %reg1, #42\n\t"
+            "more_magic %reg2, %reg3"
+            : /* outputs */ : /* inputs */ : /* clobbers */);
+
+
 
                Appendix I: References