OMAP: clockdomain: split clkdm_init()

In preparation for OMAP_CHIP() removal, split clkdm_init() into four
functions.  This allows some of them to be called multiple times: for
example, clkdm_register_clkdms() can be called once to register
clockdomains that are common to a group of SoCs, and once to register
clockdomains that are specific to a single SoC.

The appropriate order to call these functions - which is enforced
by the code - is:

1. clkdm_register_platform_funcs()
2. clkdm_register_clkdms() (can be called multiple times)
3. clkdm_register_autodeps() (optional; deprecated)
4. clkdm_complete_init()

Convert the OMAP2, 3, and 4 clockdomain init code to use these new
functions.

While here, improve documentation, and increase CodingStyle
conformance by shortening some local variable names.

Signed-off-by: Paul Walmsley <paul@pwsan.com>

4 files changed, 121 insertions, 34 deletions

diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c
index 8f0890685d7b..b73a1dc37dfb 100644
--- a/arch/arm/mach-omap2/clockdomain.c
+++ b/arch/arm/mach-omap2/clockdomain.c
@@ -257,43 +257,113 @@ static void _resolve_clkdm_deps(struct clockdomain *clkdm,
 /* Public functions */
 
 /**
- * clkdm_init - set up the clockdomain layer
- * @clkdms: optional pointer to an array of clockdomains to register
- * @init_autodeps: optional pointer to an array of autodeps to register
- * @custom_funcs: func pointers for arch specific implementations
- *
- * Set up internal state.  If a pointer to an array of clockdomains
- * @clkdms was supplied, loop through the list of clockdomains,
- * register all that are available on the current platform. Similarly,
- * if a pointer to an array of clockdomain autodependencies
- * @init_autodeps was provided, register those.  No return value.
+ * clkdm_register_platform_funcs - register clockdomain implementation fns
+ * @co: func pointers for arch specific implementations
+ *
+ * Register the list of function pointers used to implement the
+ * clockdomain functions on different OMAP SoCs.  Should be called
+ * before any other clkdm_register*() function.  Returns -EINVAL if
+ * @co is null, -EEXIST if platform functions have already been
+ * registered, or 0 upon success.
+ */
+int clkdm_register_platform_funcs(struct clkdm_ops *co)
+{
+        if (!co)
+                return -EINVAL;
+
+        if (arch_clkdm)
+                return -EEXIST;
+
+        arch_clkdm = co;
+
+        return 0;
+};
+
+/**
+ * clkdm_register_clkdms - register SoC clockdomains
+ * @cs: pointer to an array of struct clockdomain to register
+ *
+ * Register the clockdomains available on a particular OMAP SoC.  Must
+ * be called after clkdm_register_platform_funcs().  May be called
+ * multiple times.  Returns -EACCES if called before
+ * clkdm_register_platform_funcs(); -EINVAL if the argument @cs is
+ * null; or 0 upon success.
  */
-void clkdm_init(struct clockdomain **clkdms,
-                struct clkdm_autodep *init_autodeps,
-                struct clkdm_ops *custom_funcs)
+int clkdm_register_clkdms(struct clockdomain **cs)
 {
         struct clockdomain **c = NULL;
-        struct clockdomain *clkdm;
-        struct clkdm_autodep *autodep = NULL;
 
-        if (!custom_funcs)
-                WARN(1, "No custom clkdm functions registered\n");
-        else
-                arch_clkdm = custom_funcs;
+        if (!arch_clkdm)
+                return -EACCES;
+
+        if (!cs)
+                return -EINVAL;
+
+        for (c = cs; *c; c++)
+                _clkdm_register(*c);
 
-        if (clkdms)
-                for (c = clkdms; *c; c++)
-                        _clkdm_register(*c);
+        return 0;
+}
+
+/**
+ * clkdm_register_autodeps - register autodeps (if required)
+ * @ia: pointer to a static array of struct clkdm_autodep to register
+ *
+ * Register clockdomain "automatic dependencies."  These are
+ * clockdomain wakeup and sleep dependencies that are automatically
+ * added whenever the first clock inside a clockdomain is enabled, and
+ * removed whenever the last clock inside a clockdomain is disabled.
+ * These are currently only used on OMAP3 devices, and are deprecated,
+ * since they waste energy.  However, until the OMAP2/3 IP block
+ * enable/disable sequence can be converted to match the OMAP4
+ * sequence, they are needed.
+ *
+ * Must be called only after all of the SoC clockdomains are
+ * registered, since the function will resolve autodep clockdomain
+ * names into clockdomain pointers.
+ *
+ * The struct clkdm_autodep @ia array must be static, as this function
+ * does not copy the array elements.
+ *
+ * Returns -EACCES if called before any clockdomains have been
+ * registered, -EINVAL if called with a null @ia argument, -EEXIST if
+ * autodeps have already been registered, or 0 upon success.
+ */
+int clkdm_register_autodeps(struct clkdm_autodep *ia)
+{
+        struct clkdm_autodep *a = NULL;
+
+        if (list_empty(&clkdm_list))
+                return -EACCES;
+
+        if (!ia)
+                return -EINVAL;
 
-        autodeps = init_autodeps;
         if (autodeps)
-                for (autodep = autodeps; autodep->clkdm.ptr; autodep++)
-                        _autodep_lookup(autodep);
+                return -EEXIST;
+
+        autodeps = ia;
+        for (a = autodeps; a->clkdm.ptr; a++)
+                _autodep_lookup(a);
+
+        return 0;
+}
+
+/**
+ * clkdm_complete_init - set up the clockdomain layer
+ *
+ * Put all clockdomains into software-supervised mode; PM code should
+ * later enable hardware-supervised mode as appropriate.  Must be
+ * called after clkdm_register_clkdms().  Returns -EACCES if called
+ * before clkdm_register_clkdms(), or 0 upon success.
+ */
+int clkdm_complete_init(void)
+{
+        struct clockdomain *clkdm;
+
+        if (list_empty(&clkdm_list))
+                return -EACCES;
 
-        /*
-         * Put all clockdomains into software-supervised mode; PM code
-         * should later enable hardware-supervised mode as appropriate
-         */
         list_for_each_entry(clkdm, &clkdm_list, node) {
                 if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
                         clkdm_wakeup(clkdm);
@@ -306,6 +376,8 @@ void clkdm_init(struct clockdomain **clkdms,
                 _resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
                 clkdm_clear_all_sleepdeps(clkdm);
         }
+
+        return 0;
 }
 
 /**
diff --git a/arch/arm/mach-omap2/clockdomain.h b/arch/arm/mach-omap2/clockdomain.h
index 1e50c88b8a07..0d879ff490d1 100644
--- a/arch/arm/mach-omap2/clockdomain.h
+++ b/arch/arm/mach-omap2/clockdomain.h
@@ -166,8 +166,11 @@ struct clkdm_ops {
         int     (*clkdm_clk_disable)(struct clockdomain *clkdm);
 };
 
-void clkdm_init(struct clockdomain **clkdms, struct clkdm_autodep *autodeps,
-                        struct clkdm_ops *custom_funcs);
+int clkdm_register_platform_funcs(struct clkdm_ops *co);
+int clkdm_register_autodeps(struct clkdm_autodep *ia);
+int clkdm_register_clkdms(struct clockdomain **c);
+int clkdm_complete_init(void);
+
 struct clockdomain *clkdm_lookup(const char *name);
 
 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
diff --git a/arch/arm/mach-omap2/clockdomains2xxx_3xxx_data.c b/arch/arm/mach-omap2/clockdomains2xxx_3xxx_data.c
index 13bde95b6790..148a3e84162c 100644
--- a/arch/arm/mach-omap2/clockdomains2xxx_3xxx_data.c
+++ b/arch/arm/mach-omap2/clockdomains2xxx_3xxx_data.c
@@ -857,12 +857,21 @@ static struct clockdomain *clockdomains_omap2[] __initdata = {
         NULL,
 };
 
+static void __init omap2_3_clockdomains_init(void)
+{
+        clkdm_register_clkdms(clockdomains_omap2);
+        clkdm_register_autodeps(clkdm_autodeps);
+        clkdm_complete_init();
+}
+
 void __init omap2xxx_clockdomains_init(void)
 {
-        clkdm_init(clockdomains_omap2, clkdm_autodeps, &omap2_clkdm_operations);
+        clkdm_register_platform_funcs(&omap2_clkdm_operations);
+        omap2_3_clockdomains_init();
 }
 
 void __init omap3xxx_clockdomains_init(void)
 {
-        clkdm_init(clockdomains_omap2, clkdm_autodeps, &omap3_clkdm_operations);
+        clkdm_register_platform_funcs(&omap3_clkdm_operations);
+        omap2_3_clockdomains_init();
 }
diff --git a/arch/arm/mach-omap2/clockdomains44xx_data.c b/arch/arm/mach-omap2/clockdomains44xx_data.c
index dccc651fa0d0..c75411a62207 100644
--- a/arch/arm/mach-omap2/clockdomains44xx_data.c
+++ b/arch/arm/mach-omap2/clockdomains44xx_data.c
@@ -685,7 +685,10 @@ static struct clockdomain *clockdomains_omap44xx[] __initdata = {
         NULL
 };
 
+
 void __init omap44xx_clockdomains_init(void)
 {
-        clkdm_init(clockdomains_omap44xx, NULL, &omap4_clkdm_operations);
+        clkdm_register_platform_funcs(&omap4_clkdm_operations);
+        clkdm_register_clkdms(clockdomains_omap44xx);
+        clkdm_complete_init();
 }