ARM: at91: cpuidle: Convert to platform driver

Using the platform driver model is a good way to separate the cpuidle specific
code from the low level pm code. It allows to remove the dependency between
these two components.

The platform_device is located in the pm code and a 'set' function has been
added to set the standby function from the AT91_SOC_START initialization
function. Each SoC with a cpuidle driver will set the standby function in the
platform_data field at init time. Then pm code will register the cpuidle
platform device.

The cpuidle driver will register the platform_driver and use the device's
platform_data as a standby callback in the idle path.

The at91_pm_enter function contains a { if then else } based on cpu_is_xx
similar to what was in cpuidle. This is considered dangerous when adding a new
SoC. Like the cpuidle driver, a standby ops is defined and assigned when the
SoC init function specifies what is its standby function and reused in the
at91_pm_enter's 'case' block.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 19 insertions, 8 deletions

diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index 15afb5d9271f..9986542e8060 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -39,6 +39,8 @@
 #include "at91_rstc.h"
 #include "at91_shdwc.h"
 
+static void (*at91_pm_standby)(void);
+
 static void __init show_reset_status(void)
 {
         static char reset[] __initdata = "reset";
@@ -266,14 +268,8 @@ static int at91_pm_enter(suspend_state_t state)
                          * For ARM 926 based chips, this requirement is weaker
                          * as at91sam9 can access a RAM in self-refresh mode.
                          */
-                        if (cpu_is_at91rm9200())
-                                at91rm9200_standby();
-                        else if (cpu_is_at91sam9g45())
-                                at91sam9g45_standby();
-                        else if (cpu_is_at91sam9263())
-                                at91sam9263_standby();
-                        else
-                                at91sam9_standby();
+                        if (at91_pm_standby)
+                                at91_pm_standby();
                         break;
 
                 case PM_SUSPEND_ON:
@@ -314,6 +310,18 @@ static const struct platform_suspend_ops at91_pm_ops = {
         .end    = at91_pm_end,
 };
 
+static struct platform_device at91_cpuidle_device = {
+        .name = "cpuidle-at91",
+};
+
+void at91_pm_set_standby(void (*at91_standby)(void))
+{
+        if (at91_standby) {
+                at91_cpuidle_device.dev.platform_data = at91_standby;
+                at91_pm_standby = at91_standby;
+        }
+}
+
 static int __init at91_pm_init(void)
 {
 #ifdef CONFIG_AT91_SLOW_CLOCK
@@ -325,6 +333,9 @@ static int __init at91_pm_init(void)
         /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
         if (cpu_is_at91rm9200())
                 at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0);
+        
+        if (at91_cpuidle_device.dev.platform_data)
+                platform_device_register(&at91_cpuidle_device);
 
         suspend_set_ops(&at91_pm_ops);