greybus: arche-platform: Power-off unipro subsystem upon suspend

Switch off APBs/SVC/Switch in the suspend call notifier. Note that
this is an interim solution to enable fishfooding.

Testing done:
 - Passed QA sanity test on EVT1.5
 - Suspend current measured at ~70mW

Signed-off-by: David Lin <dtwlin@google.com>
Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
[vaibhav.hiremath@linaro.org: Updated commit description]
Tested-by: Sandeep Patil <sspatil@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
index 48cdb0f..3ff4f69 100644 (file)
--- a/drivers/staging/greybus/arche-platform.c
+++ b/drivers/staging/greybus/arche-platform.c
@@ -19,6 +19,7 @@
 #include <linux/pm.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
+#include <linux/suspend.h>
 #include <linux/time.h>
 #include "arche_platform.h"
 
@@ -56,6 +57,7 @@ struct arche_platform_drvdata {
        int wake_detect_irq;
        spinlock_t lock;
        unsigned long wake_detect_start;
+       struct notifier_block pm_notifier;
 
        struct device *dev;
 };
@@ -339,6 +341,31 @@ static ssize_t state_show(struct device *dev,
 
 static DEVICE_ATTR_RW(state);
 
+static int arche_platform_pm_notifier(struct notifier_block *notifier,
+                                     unsigned long pm_event, void *unused)
+{
+       struct arche_platform_drvdata *arche_pdata =
+               container_of(notifier, struct arche_platform_drvdata,
+                            pm_notifier);
+
+       switch (pm_event) {
+       case PM_SUSPEND_PREPARE:
+               if (arche_pdata->state != ARCHE_PLATFORM_STATE_ACTIVE)
+                       return NOTIFY_STOP;
+               device_for_each_child(arche_pdata->dev, NULL, apb_poweroff);
+               arche_platform_poweroff_seq(arche_pdata);
+               break;
+       case PM_POST_SUSPEND:
+               arche_platform_coldboot_seq(arche_pdata);
+               assert_wakedetect(arche_pdata);
+               break;
+       default:
+               break;
+       }
+
+       return NOTIFY_DONE;
+}
+
 static int arche_platform_probe(struct platform_device *pdev)
 {
        struct arche_platform_drvdata *arche_pdata;
@@ -474,6 +501,13 @@ static int arche_platform_probe(struct platform_device *pdev)
 
        assert_wakedetect(arche_pdata);
 
+       arche_pdata->pm_notifier.notifier_call = arche_platform_pm_notifier;
+       ret = register_pm_notifier(&arche_pdata->pm_notifier);
+       if (ret) {
+               dev_err(dev, "failed to register pm notifier %d\n", ret);
+               goto err_populate;
+       }
+
        dev_info(dev, "Device registered successfully\n");
        return 0;
 
@@ -497,6 +531,7 @@ static int arche_platform_remove(struct platform_device *pdev)
 {
        struct arche_platform_drvdata *arche_pdata = platform_get_drvdata(pdev);
 
+       unregister_pm_notifier(&arche_pdata->pm_notifier);
        device_remove_file(&pdev->dev, &dev_attr_state);
        device_for_each_child(&pdev->dev, NULL, arche_remove_child);
        arche_platform_poweroff_seq(arche_pdata);